ORCID Profile
0000-0001-9751-4910
Current Organisation
University of Technology Sydney
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Macromolecular and Materials Chemistry | Nanochemistry and Supramolecular Chemistry | Organic Chemical Synthesis | Biologically Active Molecules | Analytical Chemistry | Organic Chemistry | Characterisation of Biological Macromolecules | Medicinal and Biomolecular Chemistry | Organic Chemical Synthesis | Sensor (Chemical And Bio-) Technology | Analytical Spectrometry | Physical Chemistry (Incl. Structural) | Physical Organic Chemistry | Proteins and Peptides | Structural Chemistry and Spectroscopy | Structural Biology (incl. Macromolecular Modelling) | Supramolecular Chemistry |
ANZSRC Socio-Economic Objective (SEO)
Expanding Knowledge in the Chemical Sciences | Expanding Knowledge in the Biological Sciences | Expanding Knowledge in the Physical Sciences | Control of Animal Pests, Diseases and Exotic Species in Farmland, Arable Cropland and Permanent Cropland Environments | Physical and Chemical Conditions of Water not elsewhere classified | Higher education | Occupational training | Expanding Knowledge in the Agricultural and Veterinary Sciences
Related Links
Publications
Binding and Transport Properties of a Benzo[b]thiophene‐Based Mono‐(thio)urea Library
Publisher: Wiley
Date: 21-01-2022
Abstract: Using the chemical versatility of the benzo[ b ]thiophene motif, an extensive library of 24 (thio)urea receptors, with different binding properties and lipophilicities, was prepared and included α,α‐, α,β‐, β,β‐, β,γ‐, α,γ‐, and γ,γ‐benzo[ b ]thiophene positional isomers, as well as β‐ or γ‐benzo[ b ]thiophene‐based molecules decorated with aliphatic chains or aryl moieties with different fluorination degrees. 1 H NMR titrations, X‐ray crystallographic studies, and DFT calculations were used to study the chloride binding affinities between receptors and substrates. Experimental efflux studies suggested that the anion transmembrane transport activity is dependent on the receptors′ lipophilicity and hydrogen bonding ability. Moreover, LUV based assays indicated that anion efflux occurs mainly through an uniport mechanism. Further MD simulations showed that anion transport is highly dependent on the orientation and interactions of the receptors at the water/lipid interface.
Chem Soc Rev – staying radical
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3CS90101G
Molecular Recognition at an Organic−Aqueous Interface: Heterocalixarenes as Anion Binding Agents in Liquid Polymeric Membrane Ion-Selective Electrodes
Publisher: American Chemical Society (ACS)
Date: 09-1999
DOI: 10.1021/JA991044E
7 Supramolecular chemistry
Publisher: Royal Society of Chemistry (RSC)
Date: 2005
DOI: 10.1039/B418965P
Hydrogen bonded networks in N–alkyl substituted thiourea platinum (II) oxocarbodianion and carboxylate salts
Publisher: Royal Society of Chemistry (RSC)
Date: 2008
DOI: 10.1039/B803260B
Calix[4]pyrrole: An Old yet New Ion‐Pair Receptor
Publisher: Wiley
Date: 21-04-2005
Systematic Experimental Charge Density: Linking Structural Modifications to Electron Density Distributions
Publisher: The Chemical Society of Japan
Date: 05-01-2015
DOI: 10.1246/CL.140929
Real-Time Recording of the Cellular Effects of the Anion Transporter Prodigiosin
Publisher: Elsevier BV
Date: 04-2018
Tetrakis(thiourea)platinum(ii) oxocarbodianions salts as molecular building blocks for the synthesis of hydrogen bonded networks in the solid state
Publisher: Royal Society of Chemistry (RSC)
Date: 2006
DOI: 10.1039/B516238F
2,5-Diamidofuran anion receptors
Publisher: Elsevier BV
Date: 02-2003
Cover Picture: Voltage‐Switchable HCl Transport Enabled by Lipid Headgroup–Transporter Interactions (Angew. Chem. Int. Ed. 42/2019)
Publisher: Wiley
Date: 13-09-2019
Calix[4]pyrroles: C-rim substitution and tunability of anion binding strength
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/A700685C
Anion-directed assembly: the first fluoride-directed double helix
Publisher: Royal Society of Chemistry (RSC)
Date: 04-02-2003
DOI: 10.1039/B210847J
Abstract: The crystal structures of anion complexes of two nitroaromatic functionalised isophthalamides are reported the structures reveal assembly around anions in the solid-state and in the case of the fluoride complex of receptor 2, the formation of a double helix.
Metal−Organic Anion Receptors: Arranging Urea Hydrogen-Bond Donors to Encapsulate Sulfate Ions
Publisher: American Chemical Society (ACS)
Date: 30-03-2004
DOI: 10.1021/JA039712Q
Abstract: A new class of synthetic receptors for anions can be prepared by arranging urea hydrogen-bond donor groups on a simple metal-organic scaffold. The complex cation [PtL4]2+ (L = 8-(n-butylurea)iso-quinoline) can adopt four conformations reminiscent of calix[4]arene-based receptors "cone", "partial cone", "1,2-alternate", or "1,3-alternate". 1H NMR solution data and solid-state X-ray structures show that a "1,2-alternate" conformation is used to bind spherical halide ions while a "cone" conformation is involved in strong binding with the tetrahedral oxy-anions such as the sulfate ion even in a strongly competitive solvent such as DMSO.
Platinum(ii) nicotinamide complexes as receptors for oxo-anions
Publisher: Royal Society of Chemistry (RSC)
Date: 2001
DOI: 10.1039/B101440O
The first example of an anion–pyrrole complex
Publisher: Royal Society of Chemistry (RSC)
Date: 2001
DOI: 10.1039/B109813F
Fluorescent and colorimetric sensors for anionic species
Publisher: Elsevier BV
Date: 2018
A solid-state 35/37Cl NMR study of a chloride ion receptor and a GIPAW-DFT study of chlorine NMR interaction tensors in organic hydrochlorides
Publisher: Canadian Science Publishing
Date: 07-2011
DOI: 10.1139/V10-177
Abstract: The results of a 35/37 Cl solid-state nuclear magnetic resonance (SSNMR) study of the 1-butyl-3-methylimidazolium chloride complex of meso-octamethylcalix[4]pyrrole (1) are reported. Line shapes obtained from magic-angle-spinning and stationary powder s les collected at 9.4 and 21.1 T are analyzed to provide the 35/37 Cl quadrupolar tensor and chemical shift (CS) tensor and their relative orientation. The relatively high symmetry of the chloride ion coordination environment is manifested in the small value of the quadrupole coupling constant, C Q ( 35 Cl) = 1.0 MHz. The isotropic chemical shift of 120 ppm (with respect to NaCl(s)) is at the upper edge of the typical range seen for organic hydrochlorides. Consideration of chemical shift anisotropy (span, Ω = 50 ppm) and non-coincidence of the quadrupolar and CS tensors were essential to properly simulate the experimental spectra. The utility of gauge-including projector-augmented wave density functional theory (GIPAW-DFT) calculations of chlorine quadrupolar and CS tensors in organic chlorides was explored by validation against available benchmark experimental data for solid amino acid hydrochlorides. The calculations are shown to systematically overestimate the value of the 35 Cl quadrupole coupling constant. Additional calculations on various hydrated and solvated models of 1 are consistent with a structure in which solvent and water of hydration are absent.
A dual host approach to transmembrane transport of salts
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C0CC04430J
Abstract: A dual host approach for M(+)/Cl(-) co-transport has been shown to be effective in lipid bilayers consisting of POPC using fluorescence-based transport assays.
Self-assembly of a double dynamic covalent'' amphiphile featuring a glucose-responsive imine bond
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6CC03167F
Abstract: Glucose recognition via in situ formation of supramolecular vesicular aggregates that involve two dynamic covalent bonds.
Tris–thiourea tripodal-based molecules as chloride transmembrane transporters: insights from molecular dynamics simulations
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3SM52140K
Abstract: The interaction of six tripodal synthetic chloride transmembrane transporters with a POPC bilayer was investigated by means of molecular dynamics simulations using the general Amber force field (GAFF) for the transporters and the LIPID11 force field for phospholipids. These transporters are structurally simple molecules, based on the tris(2-aminoethyl)amine scaffold, containing three thiourea binding units coupled with three n-butyl (1), phenyl (2), fluorophenyl (3), pentafluorophenyl (4), trifluoromethylphenyl (5), or bis(trifluoromethyl)phenyl (6) substituents. The passive diffusion of 1-6⊃ Cl(-) was evaluated with the complexes initially positioned either in the water phase or inside the bilayer. In the first scenario the chloride is released in the water solution before the synthetic molecules achieve the water-lipid interface and permeate the membrane. In the latter one, only when the chloride complex reaches the interface is the anion released to the water phase, with the transporter losing the initial ggg tripodal shape. Independently of the transporter used in the membrane system, the bilayer structure is preserved and the synthetic molecules interact with the POPC molecules at the phosphate headgroup level, via N-H···O hydrogen bonds. Overall, the molecular dynamics simulations' results indicate that the small tripodal molecules in this series have a low impact on the bilayer and are able to diffuse with chloride inside the lipid environment. Indeed, these are essential conditions for these molecules to promote the transmembrane transport as anion carriers, in agreement with experimental efflux data.
Cation recognition by new diester- and diamide-calix[4]arenediquinones and a diamide-benzo-15-crown-5-calix[4]arene
Publisher: Springer Science and Business Media LLC
Date: 1994
DOI: 10.1007/BF00708992
Celebrating the 100th Anniversary of the Nobel Prize in Chemistry awarded to Alfred Werner
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C2CS90118H
A word from the new Editorial Board Chair – Professor Philip Gale, University of Southampton, UK
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3CS90095A
Stimuli-Responsive Cycloaurated OFF-ON Switchable Anion Transporters
Publisher: Wiley
Date: 11-08-2020
Abstract: Anion transporters have shown potential application as anti‐cancer agents that function by disrupting homeostasis and triggering cell death. In this research article we report switchable anion transport by gold complexes of anion transporters that are “switched on” in situ in the presence of the reducing agent GSH by decomplexation of gold. GSH is found in higher concentrations in tumors than in healthy tissue and hence this approach offers a strategy to target these systems to tumors.
Anion transport across varying lipid membranes – the effect of lipophilicity
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5CC00823A
Abstract: The anion transport properties of a range of alkyl-substituted phenylthioureas were tested in vesicles of different lipid composition.
Structural diversity in the first metal complexes of 2,5-dicarboxamidopyrroles and 2,5-dicarbothioamidopyrroles
Publisher: Royal Society of Chemistry (RSC)
Date: 2008
DOI: 10.1039/B802506A
Abstract: Metal complexes of 2,5-dicarboxamidopyrroles and 2,5-dicarbothioamidopyrroles have been structurally characterised for the first time, complementing the significant amount of work that has been reported for the analogous pyridine ligands. N,N'-Bis(3,5-dinitrophenyl)-3,4-diphenyl-1H-pyrrole-2,5-dicarboxamide forms octahedral bis(tridentate) complexes with cobalt(III) and nickel(II), where the ligands are bound to the metal centres through deprotonated pyrrole and amide N atoms. N,N'-Dibutyl-3,4-diphenyl-1H-pyrrole-2,5-dicarboxthioamide and N,N'-diphenyl-3,4-diphenyl-1H-pyrrole-2,5-dicarboxthioamide also form bis(tridentate) cobalt complexes but are only deprotonated at the pyrrole N atom, the remainder of the coordination sphere comprising the thioamide S atoms. The dibutyl derivative was isolated as a Co(II) complex, whereas the diphenyl system deposited a Co(III) complex. In contrast, N,N'-dibutyl-3,4-dichloro-1H-pyrrole-2,5-dicarboxamide was found to act as a bidentate ligand, in an octahedral cobalt(II) complex comprising of two bidentate pyrrole ligands, and two aqua ligands. Synthesis of N,N-bis(pyridin-2-ylmethyl)-3,4-diphenyl-1H-pyrrole-2,5-carboxamide gave a pyrrole ligand with increased denticity. Reaction with cobalt(II) chloride resulted in the isolation of a dinuclear helicate complex. The ligand was found to have undergone addition of a methoxy group to one of the linking methylene carbons, presumably as a result of the oxidative addition of solvent methanol.
Fluorinated synthetic anion carriers: experimental and computational insights into transmembrane chloride transport
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C8SC05155K
Abstract: A series of fluorinated tripodal tris-thioureas function as highly active anion transporters across lipid bilayers and cell membranes.
Extending the Hydrogen-bonding Array in ortho-Phenylenediamine Based Bis-ureas
Publisher: Informa UK Limited
Date: 03-2007
Synthetic ditopic receptors
Publisher: Springer Science and Business Media LLC
Date: 2001
Functionalized calix[4]pyrroles
Publisher: Walter de Gruyter GmbH
Date: 30-12-1998
Anion-binding modes in a macrocyclic amidourea
Publisher: Royal Society of Chemistry (RSC)
Date: 2006
DOI: 10.1039/B610938A
Abstract: A macrocyclic amidourea shows anion dependent binding modes with a variety of different putative anionic guests.
A dual host approach to NiSO4 extraction
Publisher: Informa UK Limited
Date: 11-11-2011
First synthesis of an expanded calixpyrrole
Publisher: Elsevier BV
Date: 12-1997
Calix[4]pyrrole-based anion transporters with tuneable transport properties
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/C0OB00128G
Abstract: Three new bis-1,2,3-triazole strapped calix[4]pyrroles have been prepared via'click' chemistry and their anion complexation and lipid bilayer transport properties studied by a combination of single crystal X-ray diffraction studies, (1)H NMR titration techniques, isothermal titration calorimetry and lipid bilayer anion transport studies in POPC vesicles. Bilayer transport efficiency for transmembrane chloride transport was found to directly depend on the length of the alkyl chain present in the bis-triazole strap.
Carboxylate complexation by a family of easy-to-make ortho-phenylenediamine based bis-ureas: studies in solution and the solid state
Publisher: Royal Society of Chemistry (RSC)
Date: 2006
DOI: 10.1039/B511963D
Synthesis of a new cylindrical calix[4]arene-calix[4]pyrrole pseudo dimer
Publisher: Elsevier BV
Date: 10-1996
Measuring anion binding at biomembrane interfaces
Publisher: Springer Science and Business Media LLC
Date: 08-08-2022
DOI: 10.1038/S41467-022-32403-Z
Abstract: The quantification of anion binding by molecular receptors within lipid bilayers remains challenging. Here we measure anion binding in lipid bilayers by creating a fluorescent macrocycle featuring a strong sulfate affinity. We find the determinants of anion binding in lipid bilayers to be different from those expected that govern anion binding in solution. Charge-dense anions H 2 PO 4 – and Cl – that prevail in dimethyl sulfoxide fail to bind to the macrocycle in lipids. In stark contrast, ClO 4 – and I – that hardly bind in dimethyl sulfoxide show surprisingly significant affinities for the macrocycle in lipids. We reveal a lipid bilayer anion binding principle that depends on anion polarisability and bilayer penetration depth of complexes leading to unexpected advantages of charge-diffuse anions. These insights enhance our understanding of how biological systems select anions and guide the design of functional molecular systems operating at biomembrane interfaces.
Design of Chiral Supramolecular Polymers Exhibiting a Negative Nonlinear Response
Publisher: American Chemical Society (ACS)
Date: 16-10-2019
Anion binding in metal-organic frameworks
Publisher: Elsevier BV
Date: 04-2021
Acylthioureas as anion transporters: The effect of intramolecular hydrogen bonding
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3OB41522H
Advances in Anion Receptor Chemistry
Publisher: Elsevier BV
Date: 2020
Chloride anion transporters inhibit growth of methicillin-resistant Staphylococcus aureus (MRSA) in vitro
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6CC03645G
Abstract: Anion transporters were tested for antimicrobial activity and shown to inhibit the growth of MRSA in vitro .
Co-transport of H+/Cl– by a synthetic prodigiosin mimic
Publisher: Royal Society of Chemistry (RSC)
Date: 2005
DOI: 10.1039/B503906A
Abstract: An amidopyrrole with appended imidazole group can bind and co-transport H+/Cl- across vesicle membranes much more effectively than an analogue with an appended pyridyl group.
Fatty Acid Fueled Transmembrane Chloride Transport
Publisher: American Chemical Society (ACS)
Date: 21-06-2019
DOI: 10.1021/JACS.9B02116
Abstract: Generation of chemical gradients across biological membranes of cellular compartments is a hallmark of all living systems. Here we report a proof-of-concept prototype transmembrane pumping system in liposomes. The pump uses fatty acid to fuel chloride transport, thus generating a transmembrane chloride gradient. Addition of fatty acid to phospholipid vesicles generates a transmembrane pH gradient (pH
Acyclic indole and carbazole-based sulfate receptors
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/C0SC00202J
Room-temperature monoclinic and low-temperature triclinic phase-transition structures ofmeso-octamethylcalix[4]pyrrole–dimethyl sulfoxide (1/1)
Publisher: International Union of Crystallography (IUCr)
Date: 06-12-2001
DOI: 10.1107/S0108270101015931
Abstract: Crystals of the title complex, C28H36N4*C2H6OS, undergo a phase transition between room temperature and 198 K, as determined by X-ray diffraction techniques. A monoclinic form is observed at room temperature, while a triclinic modification is found at 198 K, with Z' changing from 1 to 2. Differential scanning calorimetry (DSC) of the calixpyrrole-dimethyl sulfoxide complex revealed a series of phase changes between 273 and 243 K. The transition from the room-temperature monoclinic form to the low-temperature triclinic form is reversible, as determined by changes in the cell dimensions from remeasuring selected reflections at room temperature and at temperatures below 223 K. The uncomplexed calix[4]pyrrole molecule shows no phase changes occurring between room temperature and 233 K, the low-temperature limit of the DSC.
Protonophoric and mitochondrial uncoupling activity of aryl-carbamate substituted fatty acids
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D2OB02049A
Abstract: Aryl-carbamate substituted fatty acids are protonophores that uncouple mitochondrial oxidative phosphorylation. The proton transport cycle requires self-assembly into membrane permeable dimers. The findings demonstrate the anion transport capability of the carbamate group.
Anthracene-linked calix[4]pyrroles: fluorescent chemosensors for anions
Publisher: Royal Society of Chemistry (RSC)
Date: 1999
DOI: 10.1039/A905054J
Small-Molecule Uncoupling Protein Mimics: Synthetic Anion Receptors as Fatty Acid-Activated Proton Transporters
Publisher: American Chemical Society (ACS)
Date: 07-12-2016
DOI: 10.1021/JACS.6B10615
Abstract: Uncoupling proteins (UCPs) regulate energy expenditure in living cells by inducing proton leakage across the mitochondrial inner membrane, thereby uncoupling adenosine diphosphate phosphorylation from nutrient oxidation. The proton transport activity of UCP1 and UCP2 requires activation by fatty acids. We report here the first ex les of synthetic neutral anion receptors performing this biologically important fatty acid-activated function in phospholipid bilayers. We have shown that a tripodal thiourea possesses poor H
Anion recognition by N-confused calix[4]pyrrole-α-carbaldehyde and its Knoevenagel reaction derivatives
Publisher: Royal Society of Chemistry (RSC)
Date: 2007
DOI: 10.1039/B616467F
A “Holey” Supramolecular Approach to the Detection of Enzyme Activity
Publisher: Wiley
Date: 24-11-2003
Author Correction: Squaramide-based synthetic chloride transporters activate TFEB but block autophagic flux
Publisher: Springer Science and Business Media LLC
Date: 03-04-2019
DOI: 10.1038/S41419-019-1536-Y
Abstract: In the version of this article originally submitted, it was stated that the first three authors (Shaoyi_ Than, Yan Wang, Wei Xie) had contributed equally. However, in the published version this information was missing.
1,2,3-Triazole-strapped calix[4]pyrrole: a new membrane transporter for chloride
Publisher: Royal Society of Chemistry (RSC)
Date: 2009
DOI: 10.1039/B904089G
Abstract: A new triazole-strapped calix[4]pyrrole synthesised via'click' chemistry shows high affinity for chloride and lipid bilayer chloride transport properties.
Anion complexation properties of 2,2′-bisamidodipyrrolylmethanes
Publisher: Royal Society of Chemistry (RSC)
Date: 2003
DOI: 10.1039/B303532H
Biomimetic water channels: general discussion
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8FD90020E
Anion receptor chemistry: Highlights from 2011 and 2012
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3CS60316D
1,3-Diindolylureas: high affinity dihydrogen phosphate receptors
Publisher: Royal Society of Chemistry (RSC)
Date: 2008
DOI: 10.1039/B806238B
Abstract: Neutral 1,3-di(1H-indol-7-yl)ureas are selective dihydrogen phosphate receptors in polar solvent mixtures (DMSO-d(6)-25% water).
Conformational Control of Transmembrane Cl- Transport
Publisher: American Chemical Society (ACS)
Date: 25-01-2007
DOI: 10.1021/JA068067V
Interactions of Organic Halide and Nitrate Salts with meso-Octamethylcalix[4]pyrrole
Publisher: Informa UK Limited
Date: 2008
Solution and solid-state studies of 3,4-dichloro-2,5-diamidopyrroles: formation of an unusual anionic narcissistic dimerElectronic supplementary information (ESI) available: synthesis and characterisa
Publisher: Royal Society of Chemistry (RSC)
Date: 12-03-2002
DOI: 10.1039/B200980C
Abstract: 3,4-Dichoro-1H-pyrrole-2,5-dicarboxylic acid bis-phenylamide 3 and 3,4-dichoro-1H-pyrrole-2,5-dicarboxylic acid bis-butylamide 4 have been prepared and shown to deprotonate in the presence of basic anions: the X-ray crystal structure of the tetrabutylammonium salt of 3-H+ reveals the formation of a dimer in the solid state.
New Insights into the Anion Transport Selectivity and Mechanism of Tren-based Tris-(thio)ureas
Publisher: Wiley
Date: 19-06-2018
Abstract: The anion transport properties of a series of previously reported tren-based anionophores have been revisited using new assays designed to measure anion uniport. This study provides new insights into the transport mechanism and selectivity of this important class of transporters. Specifically, we report the chloride and nitrate transport selectivity of these systems and quantify sulfate transport to determine EC
2-Amidoindole-based anion receptors
Publisher: Informa UK Limited
Date: 2009
Synthesis and anion binding behaviour of diamide derivatives of pyrrole-2,5-diacetic acid
Publisher: Royal Society of Chemistry (RSC)
Date: 2004
DOI: 10.1039/B412654H
Anion Transporters and Biological Systems
Publisher: American Chemical Society (ACS)
Date: 03-04-2013
DOI: 10.1021/AR400019P
Abstract: In this Account, we discuss the development of new lipid bilayer anion transporters based on the structure of anionophoric natural products (the prodigiosins) and purely synthetic supramolecular systems. We have studied the interaction of these compounds with human cancer cell lines, and, in general, the most active anion transporter compounds possess the greatest anti-cancer properties. Initially, we describe the anion transport properties of synthetic molecules that are based on the structure of the family of natural products known as the prodiginines. Obatoclax, for ex le, is a prodiginine derivative with an indole ring that is currently in clinical trials for use as an anti-cancer drug. The anion transport properties of the compounds were correlated with their toxicity toward small cell human lung cancer GLC4 cells. We studied related compounds with enamine moieties, tambjamines, that serve as active transporters. These molecules and others in this series could depolarize acidic compartments within GLC4 cells and trigger apoptosis. In a study of the variation of lipophilicity of a series of these compounds, we observed that, as log P increases, the anion transport efficiency reaches a peak and then decreases. In addition, we discuss the anion transport properties of series of synthetic supramolecular anion receptor species. We synthesized trisureas and thioureas based on the tren backbone, and found that the thiourea compounds effectively transport anions. Fluorination of the pendant phenyl groups in this series of compounds greatly enhances the transport properties. Similar to our earlier results, the most active anion transporters reduced the viability of human cancer cell lines by depolarizing acidic compartments in GLC4 cells and triggering apoptosis. In an attempt to produce simpler transporters that obey Lipinski's Rule of Five, we synthesized simpler systems containing a single urea or thiourea group. Once again the thiourea systems, and in particular a thiourea with a pendant indole group, transported anions efficiently. A series of related compounds containing a pendant trifluoromethyl group showed enhanced transport and significant anticancer properties. Researchers still need to determine of the exact mechanism of how these compounds depolarize acidic organelles within cancer cells. However, this work shows that these transporters based upon both natural products and purely synthetic supramolecular systems transport anions, depolarize acidic compartments within cancer cells and trigger apoptosis.
Studies of lead(II) complexes of substituted calix[4]diquinones: the remarkable self-assembly of a novel redox-active 3D channel network
Publisher: Royal Society of Chemistry (RSC)
Date: 2000
DOI: 10.1039/B007061K
Delivering anion transporters to lipid bilayers in water
Publisher: American Chemical Society (ACS)
Date: 29-09-2021
DOI: 10.26434/CHEMRXIV-2021-ZSLWL
Abstract: CYCLODEXTRINS HAVE BEEN EMPLOYED AS DELIVERY AGENTS FOR LIPOPHILIC ANION TRANSPORTERS, WHICH ALLOW THEIR INCORPORATION INTO LIPID BILAYERS WITHOUT USING AN ORGANIC SOLVENT OR PRE-INCORPORATION.
Detection and remediation of organophosphorus compounds by oximate containing organogels
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5SC01864A
Abstract: A series of supramolecular diamide organogels containing a reactive compound for the remediation of organophosphorus (OP) species, in particular OP chemical warfare agents (CWAs), has been prepared in DMSO.
QSAR analysis of substituent effects on tambjamine anion transporters
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5SC03932K
Abstract: A QSAR analysis of the transmembrane anion transport activity of 43 synthetic tambjamine analogs allowed rationalization of this activity according to their lipophilicity and structural parameters.
Amido complexes of platinum(II) as receptors for the nitrate ion
Publisher: Elsevier BV
Date: 2002
Nitrophenyl derivatives of pyrrole 2,5-diamides: structural behaviour, anion binding and colour change signalled deprotonationElectronic supplementary information (ESI) available: 1H NMR, 13C NMR and
Publisher: Royal Society of Chemistry (RSC)
Date: 28-01-2003
DOI: 10.1039/B210848H
Abstract: Two new pyrrole 2,5-diamide clefts have been synthesized containing 4-nitrophenyl or 3,5-dinitrophenyl groups appended to the amide positions. The 3,5-dinitrophenyl derivative has been shown to deprotonate in the presence of fluoride, which in acetonitrile solution, gives rise to a deep blue colour.
Calix[4]pyrroles Containing Deep Cavities and Fixed Walls. Synthesis, Structural Studies, and Anion Binding Properties of the Isomeric Products Derived from the Condensation of p-Hydroxyacetoph
Publisher: American Chemical Society (ACS)
Date: 13-11-1999
DOI: 10.1021/JA993195N
Calix[4]pyridine: a new arrival in the heterocalixarene family
Publisher: Royal Society of Chemistry (RSC)
Date: 1998
DOI: 10.1039/A706018A
Anion binding vs. deprotonation in colorimetric pyrrolylamidothiourea based anion sensors
Publisher: Royal Society of Chemistry (RSC)
Date: 2006
DOI: 10.1039/B517308F
Abstract: A pyrrolylamidothiourea deprotonates in the presence of one equivalent of not only fluoride, but also acetate, benzoate or dihydrogen phosphate in DMSO solution with structural studies using synchrotron radiation confirming thiourea deprotonation in the solid state.
meso-Octamethylcalix[4]pyrrole: an old yet new transmembrane ion-pair transporter
Publisher: Royal Society of Chemistry (RSC)
Date: 2008
DOI: 10.1039/B814988G
Solvent-induced supramolecular isomerism in [Pt(SC(NH2)2)4]2+ croconate salts
Publisher: Royal Society of Chemistry (RSC)
Date: 2005
DOI: 10.1039/B513059J
Abstract: The role of solvent (and other species) in the formation of networks from tetrakis(thiourea)platinum(II) cations and croconate anions is examined, with crystallisations from DMSO giving rise to a structure containing solvent filled channels.
An Introduction to Anion Receptors Based on Organic Frameworks
Publisher: Springer Berlin Heidelberg
Date: 2008
DOI: 10.1007/430_2007_069
Crystallographic and Solution Anion Binding Studies of Bis-amidofurans and Thiophenes
Publisher: Informa UK Limited
Date: 10-2004
Thiosquaramides: PH switchable anion transporters
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4SC01629G
Abstract: Thiosquaramides show pH controlled anion transport properties in lipid bilayers.
Synthesis and Electrochemical Polymerisation of Calix[4]pyrroles Containing N-substituted Pyrrole Moieties
Publisher: Informa UK Limited
Date: 07-2001
Small‐Molecule Lipid‐Bilayer Anion Transporters for Biological Applications
Publisher: Wiley
Date: 02-01-2013
Abstract: The development of small-molecule lipid-bilayer anion transporters for potential future use in channel replacement therapy for the treatment of diseases caused by dysregulation of anion transport (such as cystic fibrosis), and in treating cancer by perturbing chemical gradients within cells, thus triggering apoptosis, is an area of intense current interest. This Minireview looks at recent developments in the design of small-molecule transmembrane anion transporters and focuses on the progress so far in employing these compounds in biological systems.
Hydrogen bond-mediated recognition of the chemical warfare agent soman (GD)
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2CC31096A
Abstract: NMR titration studies in acetonitrile-d(3)/DMSO-d(6) mixtures demonstrate that diindolylurea-based receptors can form complexes with the organophosphorus nerve agent soman in organic solution.
Accurate Method To Quantify Binding in Supramolecular Chemistry
Publisher: American Chemical Society (ACS)
Date: 08-2013
DOI: 10.1021/JO400626P
Abstract: An approach for accurate and comparable measurement of host-guest binding affinities is introduced whereby differences in binding strength (ΔlogKass values) are measured between two host molecules toward a particular guest under identical solvent conditions. Measuring differences instead of absolute values enables obtaining highly accurate results, because many of the uncertainty sources (the solvation/association state of the guest in solution, deviations in solvent composition, etc.) cancel out. As a proof of concept, this method was applied to the measurement of the binding strength of 28 synthetic anion receptors toward acetate in acetonitrile containing 0.5% water. The receptors included differently substituted indolocarbazoles, ureas, thioureas, and some others. Possible deprotonation of more acidic receptors of each compound class by acetate was checked by measuring their acidities (ΔpKa values) relative to acetic acid in the same solvent. A self-consistent (consistency standard deviation 0.04 log units) binding affinity scale ranging for around 2.7 log units was constructed from the results. Absolute logKass values were found by anchoring the scale to the absolute logKass values of two receptor molecules, determined independently by direct measurements. This new approach is expected to find use in accurate quantification of a wide range of binding processes relevant to supramolecular chemistry.
Coumarin-bisureas as potent fluorescent transmembrane anion transporters
Publisher: American Chemical Society (ACS)
Date: 07-10-2021
DOI: 10.26434/CHEMRXIV-2021-WD9SD
Abstract: A series of fluorescent coumarin bis-ureas have been synthesised and their anion transport properties studied. The compounds function as highly potent HCl co-transport agents in lipid bilayer membranes.
Hydrogen bonding networks and anion coordination in (η6-arene)Cr(CO)3 complexes: metal carbonyls as hydrogen bond acceptors
Publisher: Royal Society of Chemistry (RSC)
Date: 2000
DOI: 10.1039/A909861E
Calixpyrroles
Publisher: Royal Society of Chemistry (RSC)
Date: 1998
DOI: 10.1039/A706280J
Changing and challenging times for service crystallography
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2SC00955B
Tris-ureas as transmembrane anion transporters
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6DT02046A
Abstract: Tris ureas can mediate the exchange of Cl − /NO 3 − and also Cl − /HCO 3 − across bilayer membranes.
Anion transport and supramolecular medicinal chemistry
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7CS00159B
Abstract: New approaches to the transmembrane transport of anions are discussed in this review.
Anion coordination and anion-templated assembly: Highlights from 2002 to 2004
Publisher: Elsevier BV
Date: 12-2006
Benzimidazole-based anion receptors exhibiting selectivity for lactate over pyruvate
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2OB26299A
Abstract: The influence of anions on tautomerism in benzimidazole containing anion receptors has been studied via a variety of techniques in both solution and the solid state. The results show that hydrogen bonding interactions between the receptors and guests have a significant effect of the nature of the tautomer present. The compounds show a preference for complexation of lactate over pyruvate.
Selective anion transport mediated by strap-extended calixpyrroles
Publisher: World Scientific Pub Co Pte Lt
Date: 2020
DOI: 10.1142/S1088424619501591
Abstract: Synthetic anion receptors that facilitate transmembrane chloride transport are of interest as potential therapeutic agents for cancer and cystic fibrosis. Transporters selective for chloride over protons are desired for therapeutic applications to avoid autophagy inhibition and cytotoxicity. Ex les of such compounds are rare because the majority of anion transporters can interact with the carboxylate head groups of fatty acids leading to proton leakage. In this paper, we report the synthesis, anion binding and transmembrane anion transport properties of two novel bis-triazole-functionalized calixpyrroles with extended straps, and compare them to previously reported shorter-strap analogues known to exhibit high Cl [Formula: see text] H[Formula: see text] selectivity. We demonstrate improved chloride transport activities of the strap-extended compounds that likely benefit from increased lipophilicity, and reduced Cl [Formula: see text] H[Formula: see text] selectivity due to the larger anion binding cavities facilitating interaction with fatty acids. The results are instructive for future design of ideal anion transporters with potent activity and high selectivity against proton leakage.
Indole-based perenosins as highly potent HCl transporters and potential anti-cancer agents
Publisher: Springer Science and Business Media LLC
Date: 24-08-2017
DOI: 10.1038/S41598-017-09645-9
Abstract: Prodigiosin is one of the most potent anion transporters in lipid bilayer membranes reported to date. Inspired by the structure of this natural product, we have recently designed and synthesised a new class of H + /Cl − cotransporters named ‘perenosins’. Here we report a new library of indole-based perenosins and their anion transport properties. The new transporters demonstrated superior transmembrane transport efficiency when compared to other indole-based transporters, due to favourable encapsulating effects from the substituents on the perenosin backbone. Anion transport assays were used to determine the mechanism of chloride transport revealing that the compounds function as ‘strict’ HCl cotransporters. Cell viability studies showed that some compounds specifically trigger late-onset cell death after 72 h with a unique correlation to the position of alkyl chains on the perenosins. Further investigations of cell death mechanism showed a mixture of cell cycle arrest and apoptosis was responsible for the observed decrease in cell viability.
Anion binding and transport properties of cyclic 2,6-bis(1,2,3-triazol-1-yl)pyridines
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4OB02236J
Abstract: The anion binding and membrane transport properties of a series of cyclic 2,6-bis-(1,2,3-triazolyl)-pyridine receptors with thiourea functionalities are reported.
Delivering anion transporters to lipid bilayers in water
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1OB02041B
Abstract: Cyclodextrins have been employed as delivery agents for lipophilic anion transporters, which allow their incorporation into lipid bilayers without using an organic solvent or pre-incorporation.
Network formation by a pyrrole functionalized isophthalamide
Publisher: Royal Society of Chemistry (RSC)
Date: 2006
DOI: 10.1039/B612524G
Isophthalamides and 2,6-dicarboxamidopyridines with pendant indole groups: a ‘twisted’ binding mode for selective fluoride recognition
Publisher: Royal Society of Chemistry (RSC)
Date: 2007
DOI: 10.1039/B703905K
Abstract: Two cleft-like anion receptors have been synthesised that contain indole hydrogen-bond donors and show fluoride selectively in a DMSO-water solution with crystallographic studies showing a 'twisted' binding mode for fluoride in the solid state.
Fluorescent Anthracene-based Anion Receptors
Publisher: Informa UK Limited
Date: 06-2008
Halide-selective, proton-coupled anion transport by phenylthiosemicarbazones
Publisher: American Chemical Society (ACS)
Date: 24-08-2021
DOI: 10.26434/CHEMRXIV-2021-M85ZK
Abstract: Phenylthiosemicarbazones (PTSCs) are proton-coupled anion transporters with pH-switchable behaviour known to be regulated by an imine protonation equilibrium. Previously, chloride/nitrate exchange by PTSCs was found to be inactive at pH 7.2 due to locking of the thiourea anion binding site by an intramolecular hydrogen bond, and switched ON upon imine protonation at pH 4.5. The rate-determining process of the pH switch, however, was not examined. We here develop a new series of PTSCs and demonstrate their conformational behaviour by X-ray crystallographic analysis and pH-switchable anion transport properties by liposomal assays. We report the surprising finding that these compounds are extremely selective for halides over oxyanions in membrane transport. Owing to the high chloride over nitrate selectivity, the pH-dependent chloride/nitrate exchange of PTSCs originates from the rate-limiting nitrate transport process being inhibited at neutral pH, whereas chloride transport remains efficient under both neutral and acidic conditions.
Chloride, carboxylate and carbonate transport by ortho-phenylenediamine-based bisureas
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C2SC21112B
Anion Recognition and Sensing: The State of the Art and Future Perspectives
Publisher: Wiley
Date: 30-01-2001
DOI: 10.1002/1521-3773(20010202)40:3<486::AID-ANIE486>3.0.CO;2-P
From Anion Receptors to Transporters
Publisher: American Chemical Society (ACS)
Date: 05-01-2011
DOI: 10.1021/AR100134P
Abstract: Cystic fibrosis is the most well-known of a variety of diseases termed channelopathies, in which the regulation of ion transport across cell membranes is so disrupted that the threshold of a pathology is passed. The human toll exacted by these diseases has led a number of research groups, including our own, to create compounds that mediate ion transport across lipid bilayers. In this Account, we discuss three classes of synthetic compounds that were refined to bind and transport anions across lipid bilayer membranes. All of the compounds were originally designed as anion receptors, that is, species that would simply create stable complexes with anions, but were then further developed as transporters. By studying structurally simple systems and varying their properties to change the degree of preorganization, the affinity for anions, or the lipophilicity, we have begun to rationalize why particular anion transport mechanisms (cotransport or antiport processes) occur in particular cases. For ex le, we have studied the chloride transport properties of receptors based on the closely related structures of isophthalamide and pyridine-2,6-dicarboxamide: the central ring in each case was augmented with pendant methylimidazole groups designed to cotransport H(+) and Cl(-). We observed that the more preorganized pyridine-based receptor was the more efficient transporter, a finding replicated with a series of isophthalamides in which one contained hydroxyl groups designed to preorganize the receptor. This latter class of compound, together with the natural product prodigiosin, can transport bicarbonate (as part of a chloride/bicarbonate antiport process) across lipid bilayer membranes. We have also studied the membrane transport properties of calix[4]pyrroles. Although the parent meso-octamethylcalix[4]pyrrole functions solely as a Cs(+)/Cl(-) cotransporter, other compounds with increased anion affinities can function through an antiport process. One ex le is octafluoro-meso-octamethylcalix[4]pyrrole with its electron-withdrawing substituents, it can operate through a chloride/bicarbonate antiport process. Moreover, calix[4]pyrroles with additional hydrogen bond donors can operate through a chloride/nitrate antiport process. Thus, increasing the affinity of the receptor in these cases allows the compound to transport an anion in the absence of a cation. Finally, we have studied the transport properties of simple thioureas and shown that these compounds are highly potent chloride/bicarbonate antiport agents that function at low concentrations. In contrast, the urea analogues are inactive. The higher hydrophobicity (reflected in higher values for the logarithm of the water-octanol partition constant, or log P) and lower polar surface areas of the thiourea compounds compared to their urea analogues may provide a clue to the high potency of these compounds. This observation might serve as a basis for designing future small-molecule transporters.
Systematic structural analysis of a series of anion receptor complexes
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3CE41503A
Tetrapodal Anion Transporters
Publisher: MDPI AG
Date: 06-11-2020
DOI: 10.3390/MOLECULES25215179
Abstract: Synthetic anion transporters that facilitate chloride transport are promising candidates for channelopathy treatments. However, most anion transporters exhibit an undesired side effect of facilitating proton transport via interacting with fatty acids present in the membrane. To address the limitation, we here report the use of a new tetrapodal scaffold to maximize the selective interaction with spherical chloride over binding the carboxylate headgroup of fatty acids. One of the new transporters demonstrated a high selectivity for chloride uniport over fatty acid-induced proton transport while being times more active in chloride uniport than strapped calixpyrroles that were previously the only class of compounds known to possess similar selectivity properties.
Blue emitting C-2-symmetrical dibenzothiazolyl substituted pyrrole, furan and thiophene
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3TC00760J
Anion complexation and electrochemical behaviour of ferrocene-appended amido-pyrrole cleftsElectronic supplementary information (ESI) available: 1H and 13C NMR spectra of 1 and 2, 1H NMR titrations of
Publisher: Royal Society of Chemistry (RSC)
Date: 31-05-2002
DOI: 10.1039/B202989H
Ferrocene-substituted calix[4]pyrrole: a new electrochemical sensor for anions involving CH⋯anion hydrogen bonds
Publisher: Elsevier BV
Date: 09-2001
Anion recognition and transport properties of sulfamide-, phosphoric triamide- and thiophosphoric triamide-based receptors
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C2CC38198B
Anion receptor chemistry: highlights from 2007
Publisher: Royal Society of Chemistry (RSC)
Date: 2009
DOI: 10.1039/B806422A
Abstract: This critical review includes advances in anion complexation in the year 2007. The review covers anion receptors that employ amides and thioamides, pyrroles and indoles, ureas and thioureas, guanidinium, ammonium, and imidazolium groups and receptors containing hydroxyl groups. In addition, receptors containing metal ions or Lewis acids are discussed along with anion-pi interactions and the membrane transport of anionic species by synthetic transporters and channels (204 references).
Structural and Molecular Recognition Studies with Acyclic Anion Receptors
Publisher: American Chemical Society (ACS)
Date: 26-05-2006
DOI: 10.1021/AR040237Q
Abstract: Acyclic molecules containing amides, ureas, and pyrrole groups have proven to be effective and selective anion-binding agents. In this Account, the structural chemistry of isophthalamide anion complexes, ortho-phenylenediamine based bis-ureas, and amidopyrroles, as well as anion-triggered deprotonation processes in neutral anion receptor systems, are discussed.
Anion carriers as potential treatments for cystic fibrosis: transport in cystic fibrosis cells, and additivity to channel-targeting drugs
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9SC04242C
Abstract: Synthetic anion transporters are active in cystic fibrosis cells, and are additive to clinically-approved drugs, suggesting new combination therapies for this lethal genetic condition.
Anion receptor chemistry: Highlights from 2016
Publisher: Elsevier BV
Date: 11-2018
A New Bis-amidinium Calix[4]arene-difluorophosphinate Network: An Unexpected but not Unwelcome Guest
Publisher: Informa UK Limited
Date: 09-2001
7 Supramolecular chemistry
Publisher: Royal Society of Chemistry (RSC)
Date: 2003
DOI: 10.1039/B212005B
Complexation of Alkali Chloride Contact Ion-Pairs Using A 2,5-Diamidopyrrole Crown Macrobicycle
Publisher: Elsevier BV
Date: 07-2001
Development of a Library of Thiophene‐Based Drug‐Like Lego Molecules: Evaluation of Their Anion Binding, Transport Properties, and Cytotoxicity
Publisher: Wiley
Date: 27-12-2019
Abstract: The anion-binding and transport properties of an extensive library of thiophene-based molecules are reported. Seventeen bis-urea positional isomers, with different binding conformations and lipophilicities, have been synthesized by appending α- or β-thiophene or α-, β-, or γ-benzo[b]thiophene moieties to an ortho-phenylenediamine central core, yielding six subsets of positional isomers. Through
Ferrocene-substituted calix[4]pyrrole modified carbon paste electrodes for anion detection in water
Publisher: Elsevier BV
Date: 06-2006
Crown Ether Appended Amidopyrrole Clefts
Publisher: Informa UK Limited
Date: 04-2003
Synthesis and Anion Binding Properties of N,N‘-Bispyrrol-2-yl-2,5-diamidopyrrole
Publisher: American Chemical Society (ACS)
Date: 15-03-2006
DOI: 10.1021/OL060193G
Anion sensing by small molecules and molecular ensembles
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4CS00179F
Abstract: This Tutorial Review provides a short survey of anion sensing by small molecule anion receptors, molecular ensembles and chemodosimeters.
pH switchable anion transport by an oxothiosquaramide
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5CC03625A
Abstract: An oxothiosquaramide was shown to bind to chloride through hydrogen bonding interactions in DMSO and found to exhibit pH switchable chloride transport across phospholipid bilayers via an antiport transport mechanism.
Supramolecular chemistry: defined
Publisher: Informa UK Limited
Date: 05-06-2017
Highly effective yet simple transmembrane anion transporters based upon ortho-phenylenediamine bis-ureas
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4CC05519E
Abstract: Simple, highly fluorinated receptors are shown to function as effective transmembrane anion transporters with the most active transporters rivalling the transport efficacy of natural anion transporter prodigiosin for chloride/bicarbonate antiport.
Organoplatinum Compounds as Anion‐Tuneable Uphill Hydroxide Transporters
Publisher: Wiley
Date: 11-03-2022
Abstract: Active transport of ions uphill, creating a concentration gradient across a cell membrane, is essential for life. It remains a significant challenge to develop synthetic systems that allow active uphill transport. Here, a transport process fuelled by organometallic compounds is reported that creates a pH gradient. The hydrolysis reaction of Pt II complexes results in the formation of aqua complexes that established rapid transmembrane movement (“flip‐flop”) of neutral Pt−OH species, leading to protonation of the OH group in the inner leaflet, generating OH − ions, and so increasing the pH in the intravesicular solution. The organoplatinum complex effectively transports bound hydroxide ions across the membrane in a neutral complex. The initial net flow of the Pt II complex into the vesicles generates a positive electric potential that can further drive uphill transport because the electric potential is opposed to the chemical potential of OH − . The OH − ions equilibrate with this transmembrane electric potential but cannot remove it due to the relatively low permeability of the charged species. As a result, effective hydroxide transport against its concentration gradient can be achieved, and multiple additions can continuously drive the generation of OH − against its concentration gradient up to ΔpH . Moreover, the external addition of different anions can control the generation of OH − depending on their anion binding affinity. When anions displayed very high binding affinities towards Pt II compounds, such as halides, the external anions could dissipate the pH gradient. In contrast, a further pH increase was observed for weak binding anions, such as sulfate, due to the increase of positive electric potential.
Anion receptors based on organic frameworks: highlights from 2005 and 2006
Publisher: Royal Society of Chemistry (RSC)
Date: 2008
DOI: 10.1039/B715825D
Abstract: This critical review covers advances in anion complexation chemistry related to receptors based on organic frameworks in the years 2005-2006. The review covers anion receptors that employ amides and thioamides, pyrroles and indoles, ureas and thioureas, ammonium, guanidinium, imidazolium, and receptors containing hydroxyl groups. There is a discussion of anion templated assembly, followed by a short section outlining modelling studies of these systems. (226 references.)
Detection of nerve agent via perturbation of supramolecular gel formation
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3CC44841J
Abstract: The formation of tren-based tris-urea supramolecular gels in organic solvents is perturbed by the presence of the nerve agent soman providing a new method of sensing the presence of organophosphorus warfare agents.
A Calix[4]pyrrole-Based Selective Amino Acid Transporter
Publisher: Elsevier BV
Date: 11-2020
Cyclic peptide unguisin A is an anion receptor with high affinity for phosphate and pyrophosphate
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7OB00316A
Abstract: Unguisin A ( 1 ) is a marine-derived, GABA-containing cyclic heptapeptide with a high binding affinity for phosphates.
Further insight into the coordination of 2,5-dicarbothioamidopyrroles: the case of Cu and Co complexes
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C1DT10441A
Abstract: The coordination chemistry of 2,5-dicarbothioamidopyrrole ligands, namely N2,N5-dibutyl-3,4-diphenyl-1H-pyrrole-2,5-bis(carbothioamide) and N2,N5,3,4-tetraphenyl-1H-pyrrole-2,5-bis(carbothioamide), has been investigated with Cu(II) metal centres by means of X-ray crystallography. This resulted in the formation of the expected planar S,N,S' coordinated complex for the former ligand and unexpected ring-closure reactions, with formation of benzothiazole sidearms, for the latter. Both Cu(II) and Cu(I), used in large excess, were found to favour the ring-closure reaction, although the structural characterisation of the resulting complexes contained only Cu(II) cations, with varying coordination geometries ranging from square planar and square-based pyramidal to tetrahedral. By repeating the reaction using a slight excess of Cu(II) (2 : 1) two more different structures were obtained where the metal was coordinated to the original ligand, N2,N5,3,4-tetraphenyl-1H-pyrrole-2,5-bis(carbothioamide), or to the mixed ligand where only one of the thioamide substituents had converted to a benzothiazole. The essential role of Cu for the ring closure reaction was also established by comparing its complex with structural features of the analogous Co(II) complex, the latter revealing no ring closure to give benzothiazole substituents and co-crystallisation of a mixed Co(II)/Co(III) complex. Finally, the structure and photophysical properties of the corresponding 3,4-diphenyl-2,5-bis(benzothiozol-5-yl)-pyrrole ligand, obtained via treatment of the thioamide with K(3)[Fe(CN)(6)], were also investigated revealing a blue-centered emission.
Fluoride recognition in ‘super-extended cavity’ calix[4]pyrroles
Publisher: Royal Society of Chemistry (RSC)
Date: 2000
DOI: 10.1039/B003229H
Lower-rim ferrocenyl substituted calixarenes: New electrochemical sensors for anions
Publisher: Elsevier BV
Date: 1998
Supramolecular gels for the remediation of reactive organophosphorus compounds
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4RA07712A
Abstract: Pyridine-based gels formed with a cyclohexyl diamide gelator have been shown to undergo a gel–sol transition upon addition of the organophosphorus (OP) chemical warfare agent (CWA) simulant diethyl chlorophosphate (DCP).
Pyrrolylamidourea based anion receptors
Publisher: Royal Society of Chemistry (RSC)
Date: 2006
DOI: 10.1039/B603223K
Cytosine substituted calix[4]pyrroles: Neutral receptors for 5′-guanosine monophosphate
Publisher: Proceedings of the National Academy of Sciences
Date: 02-04-2002
Abstract: The synthesis and characterization of two cytosine-substituted calix[4]pyrrole conjugates, bearing the appended cytosine attached at either a β- or meso -pyrrolic position, is described. These systems were tested as nucleotide-selective carriers and as active components of nucleotide-sensing ion-selective electrodes at pH 6.6. Studies of carrier selectivity were made using a Pressman-type model membrane system consisting of an initial pH 6.0 aqueous phase, an intervening dichloromethane barrier containing the calix[4]pyrrole conjugate, and a receiving basic aqueous phase. Good selectivity for the Watson–Crick complementary nucleotide, 5′-guanosine monophosphate (5′-GMP), was seen in the case of the meso -linked conjugate with the relative rates of through-membrane transport being 7.7:4.1:1 for 5′-GMP, 5′-AMP, and 5′-CMP, respectively. By contrast, the β-substituted conjugate, while showing a selectivity for 5′-GMP that was enhanced relative to unsubstituted calix[4]pyrrole, was found to transport 5′-CMP roughly 4.5 times more quickly than 5′-GMP. Higher selectivities were also found for 5′-CMP when both the β- and meso -substituted conjugates were incorporated into polyvinyl chloride membranes and tested as ion selective electrodes at pH 6.6, whereas near-equal selectivities were observed for 5′-CMP and 5′-GMP in the case of unsubstituted calix[4]pyrroles. These seemingly disparate results are consistent with a picture wherein the meso -substituted cytosine calix[4]pyrrole conjugate, but not its β-linked congener, is capable of acting as a ditopic receptor, binding concurrently both the phosphate anion and nucleobase portions of 5′-GMP to the calixpyrrole core and cytosine “tails” of the molecule, respectively, with the effect of this binding being most apparent under the conditions of the transport experiments.
Synthetic transporters for sulfate: a new method for the direct detection of lipid bilayer sulfate transport
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3SC52006D
Acridinone-based anion receptors and sensors
Publisher: Royal Society of Chemistry (RSC)
Date: 2007
DOI: 10.1039/B618072H
Abstract: The interaction of a variety of acridinone derivatives containing hydrogen-bond donor groups in the 4- and 5-positions with anions demonstrate the potential of this new scaffold in anion receptor and sensor design.
Carbamate complexation by urea-based receptors: studies in solution and the solid state
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/B917140A
Abstract: The interactions of a series of urea based neutral hydrogen bond donor anion receptors have been investigated with i) alkylcarbamate anions formed by the reaction of carbon dioxide with primary aliphatic amines and ii) the zwitterionic species formed by the reaction of carbon dioxide with 1,4,5,6-tetrahydropyrimidine. Significant downfield chemical shift changes were observed for the urea NH protons in many cases, consistent with host : anion hydrogen bonding interactions, and thus stabilisation of the carbon dioxide bound species. In the case of the alkylammonium-alkylcarbamate salts, this represents successful competition with electrostatic interactions between the alkylcarbamate and alkylammonium components of the salt. A synchrotron structure of a ternary complex formed by an amide appended diindolylurea, the ammonium carbamate salt formed by 1,3-diaminopropane and CO(2) and 18-crown-6, was elucidated and shows the carbamate group bound by six hydrogen bonds (accepting five and donating one) to the functionalised diindolylurea.
Supramolecular chemistry: from complexes to complexity
Publisher: The Royal Society
Date: 15-01-2019
Electron density distribution studies as a tool to explore the behaviour of thiourea-based anion receptors
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5CE00213C
Abstract: Building on previous studies of anion-receptor complexes based on a urea scaffold substituted symmetrically with electron-withdrawing nitro groups, the electron density distribution in an analogous thiourea receptor complex and the related asymmetrically substituted urea and thiourea receptors are described.
Bis(tetrabutylammonium) isophthalate 1-phenyl-3-[2,4,5-tris(3-phenylureido)phenyl]urea: a synchrotron study
Publisher: International Union of Crystallography (IUCr)
Date: 21-04-2006
DOI: 10.1107/S1600536806009135
Abstract: The structure of 2C 16 H 36 N + ·C 8 H 4 O 4 2− ·C 34 H 30 N 8 O 4 , comprises tapes of encapsulated hydrogen-bonded isophthalate anions which are arranged into parallel sheets interleaved with tetrabutylammonium layers each of the two independent neutral molecules is disposed about a centre of inversion.
Organic salt inclusion: the first crystal structures of anion complexes of N-confused calix[4]pyrrole
Publisher: Royal Society of Chemistry (RSC)
Date: 2006
DOI: 10.1039/B604128K
Bis-amidinium calixarenes: Templates for self-assembled receptors
Publisher: Elsevier BV
Date: 05-1998
Fluorescent carbazolylurea- and carbazolylthiourea-based anion receptors and sensors
Publisher: Informa UK Limited
Date: 07-06-2010
Transmembrane anion transport by synthetic systems
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C1CC12061A
A highly selective superphane for ReO4− recognition and extraction
Publisher: Elsevier BV
Date: 05-2022
Organoplatinum Compounds as Anion‐Tuneable Uphill Hydroxide Transporters
Publisher: Wiley
Date: 11-03-2022
Abstract: Active transport of ions uphill, creating a concentration gradient across a cell membrane, is essential for life. It remains a significant challenge to develop synthetic systems that allow active uphill transport. Here, a transport process fuelled by organometallic compounds is reported that creates a pH gradient. The hydrolysis reaction of Pt II complexes results in the formation of aqua complexes that established rapid transmembrane movement (“flip‐flop”) of neutral Pt−OH species, leading to protonation of the OH group in the inner leaflet, generating OH − ions, and so increasing the pH in the intravesicular solution. The organoplatinum complex effectively transports bound hydroxide ions across the membrane in a neutral complex. The initial net flow of the Pt II complex into the vesicles generates a positive electric potential that can further drive uphill transport because the electric potential is opposed to the chemical potential of OH − . The OH − ions equilibrate with this transmembrane electric potential but cannot remove it due to the relatively low permeability of the charged species. As a result, effective hydroxide transport against its concentration gradient can be achieved, and multiple additions can continuously drive the generation of OH − against its concentration gradient up to ΔpH . Moreover, the external addition of different anions can control the generation of OH − depending on their anion binding affinity. When anions displayed very high binding affinities towards Pt II compounds, such as halides, the external anions could dissipate the pH gradient. In contrast, a further pH increase was observed for weak binding anions, such as sulfate, due to the increase of positive electric potential.
Calix[4]pyrroles: Old Yet New Anion-Binding Agents
Publisher: American Chemical Society (ACS)
Date: 1996
DOI: 10.1021/JA960307R
Synthesis and X-ray crystal structure of a new redox-active calix[5]arene containing a totally included ethanol molecule
Publisher: Royal Society of Chemistry (RSC)
Date: 1995
DOI: 10.1039/C39950001851
Synthetic indole, carbazole, biindole and indolocarbazole-based receptors: applications in anion complexation and sensing
Publisher: Royal Society of Chemistry (RSC)
Date: 2008
DOI: 10.1039/B809508F
Abstract: Indole, biindole, carbazole and indolocarbazole-based receptors are rapidly emerging as an important new class of anion-binding agents. This Feature Article provides a comprehensive overview of the molecular recognition and structural chemistry of these neutral, yet highly effective, anion receptors and sensors.
Electrochemical measurement of switchable hydrogen bonding in an anthraquinone-based anion receptor
Publisher: Elsevier BV
Date: 12-2005
Delivering anion transporters to lipid bilayers in water
Publisher: Cambridge University Press (CUP)
Date: 29-09-2021
DOI: 10.33774/CHEMRXIV-2021-ZSLWL
Abstract: CYCLODEXTRINS HAVE BEEN EMPLOYED AS DELIVERY AGENTS FOR LIPOPHILIC ANION TRANSPORTERS, WHICH ALLOW THEIR INCORPORATION INTO LIPID BILAYERS WITHOUT USING AN ORGANIC SOLVENT OR PRE-INCORPORATION.
N,N′-Bis(3-nitrophenyl)isophthalamide tetrabutylammonium chloride
Publisher: International Union of Crystallography (IUCr)
Date: 22-02-2006
Small neutral molecular carriers for selective carboxylate transport
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2CC37468D
Mono- and bis-ferrocene 2,5-diamidopyrrole clefts: solid-state assembly, anion binding and electrochemical properties
Publisher: Elsevier BV
Date: 03-2003
Binding of Neutral Substrates by Calix[4]pyrroles
Publisher: American Chemical Society (ACS)
Date: 1996
DOI: 10.1021/JA9632217
Calixpyrroles II
Publisher: Elsevier BV
Date: 11-2001
A colourimetric calix[4]pyrrole–4-nitrophenolate based anion sensor†
Publisher: Royal Society of Chemistry (RSC)
Date: 1999
DOI: 10.1039/A905743I
Formation and X-ray crystal structures of neutral 3D networks by charge-assisted hydrogen bonds between tetrakis(thiourea)platinum(II) complexes and dicarboxylates
Publisher: Elsevier BV
Date: 03-2006
Editorial
Publisher: Informa UK Limited
Date: 19-12-2013
Disruption of a binary organogel by the chemical warfare agent soman (GD) and common organophosphorus simulants
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4TA04834B
Abstract: The chemical warfare agent (CWA) soman (GD) acts as a molecular stimulus for the disruption of an anthracene-based binary organogel prepared in cyclohexane.
A neutral upper to lower rim linked bis-calix[4]arene receptor that recognises anionic guest species
Publisher: Elsevier BV
Date: 1995
Complexity of Supramolecular Assemblies
Publisher: Wiley
Date: 26-10-2016
Oligopyrrole-based solid state self-assemblies
Publisher: Elsevier BV
Date: 10-2003
Electrochemical studies of the conformational and sodium cation complexation properties of calix[4]arenediquinones
Publisher: Royal Society of Chemistry (RSC)
Date: 1994
DOI: 10.1039/FT9949002931
Supramolecular methods: the chloride/nitrate transmembrane exchange assay
Publisher: Informa UK Limited
Date: 11-02-2019
Calix[4]pyrrole as a Chloride Anion Receptor: Solvent and Countercation Effects
Publisher: American Chemical Society (ACS)
Date: 25-08-2006
DOI: 10.1021/JA064012H
A synergistic approach to anion antiport
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C1DT10213C
Abstract: A synergistic approach to Cl(-)/HCO(3)(-) antiport has been demonstrated in POPC lipid bilayers using an ion selective electrode assay showing that, when using combinations of carriers each optimised for a particular component of the transport process, enhanced rates of transport are observed.
Nonprotonophoric Electrogenic Cl− Transport Mediated by Valinomycin-like Carriers
Publisher: Elsevier BV
Date: 07-2016
Hydrogen-bonding pyrrolic amide cleft anion receptors
Publisher: Elsevier BV
Date: 07-2001
Subcellular targeted anionophores
Publisher: American Chemical Society (ACS)
Date: 27-06-2023
DOI: 10.26434/CHEMRXIV-2023-M3P3J
Abstract: Synthetic anion transporters that mediate electroneutral (H+/Cl-) transport have demonstrated anti-cancer activity due to their ability to disrupt subcellular homeostasis. Elucidation of the cell death mechanism revealed the transporters’ ability to neutralise lysosomal pH gradients and inhibit autophagy. However, their effect on other subcellular compartments is unknown. Herein, we disclose the first subcellular targeted anionophores that accumulate in various membrane bound organelles to bias their natural propensity to depolarise lysosomes. The series of naphthalimide-based transporters were studied by confocal microscopy, and were found to accumulate in different subcellular organelles. The analogues that contained endoplasmic reticulum (ER)- and lysosomal targeting motifs showed enhanced the H+/Cl- transport ability compared to their non-targeted analogues. Moreover, ER and lysosomal localisation was found to enhance the cytotoxic effect of the transporters on cancerous cells. Our work provides an alternative approach in the design of therapeutically focused synthetic anion transporters and an insight into possible subcellular compartment-specific effects on homeostasis.
A Two-Dimensional Metallacycle Cross-Linked Switchable Polymer for Fast and Highly Efficient Phosphorylated Peptide Enrichment
Publisher: American Chemical Society (ACS)
Date: 10-09-2020
DOI: 10.26434/CHEMRXIV.11292119.V2
Abstract: The selective and efficient capture of phosphopeptides is critical for comprehensive and in-depth phosphoproteome analysis. However, this remains a significant challenge due to the inherently low abundance of these species in complex bio-s les. In this paper, we report a switchable two-dimensional (2D) supramolecular polymer that can serve as an ideal platform for the enrichment of phosphopeptides. A positively charged metallacycle incorporated into the polymer endows the material with a high affinity for phosphopeptides. Importantly, the stimuli-responsive nature of the polymer facilitates switchable binding affinity of phosphopeptides, resulting in its excellent performance in phosphopeptide enrichment and separation from model proteins. The polymer has a high enrichment capacity (165 mg/g) and detection sensitivity (2 fmol), high enrichment recovery (88%), excellent specificity, and rapid enrichment and separation properties. Additionally, we have demonstrated the capture of phosphopeptides from the tryptic digest of real bio-s les illustrating the potential of this polymeric material in phosphoproteomic studies.
A Two-Dimensional Metallacycle Cross-Linked Switchable Polymer for Fast and Highly Efficient Phosphorylated Peptide Enrichment
Publisher: American Chemical Society (ACS)
Date: 04-12-2019
DOI: 10.26434/CHEMRXIV.11292119.V1
Abstract: The selective and efficient capture of phosphopeptides is critical for comprehensive and in-depth phosphoproteome analysis. However, this remains a significant challenge due to the inherently low abundance of these species in complex bio-s les. In this paper, we report a switchable two-dimensional (2D) supramolecular polymer that can serve as an ideal platform for the enrichment of phosphopeptides. A positively charged metallacycle incorporated into the polymer endows the material with a high affinity for phosphopeptides. Importantly, the stimuli-responsive nature of the polymer facilitates switchable binding affinity of phosphopeptides, resulting in its excellent performance in phosphopeptide enrichment and separation from model proteins. The polymer has a high enrichment capacity (165 mg/g) and detection sensitivity (2 fmol), high enrichment recovery (88%), excellent specificity, and rapid enrichment and separation properties. Additionally, we have demonstrated the capture of phosphopeptides from the tryptic digest of real bio-s les illustrating the potential of this polymeric material in phosphoproteomic studies.
Anion receptor chemistry
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C0CC00656D
Abstract: This article looks back at advances made in anion complexation since the turn of the millennium and ahead to the application of receptors in areas such as organocatalysis and nanotechnology.
Metal-induced pre-organisation for anion recognition in a neutral platinum-containing receptor
Publisher: Royal Society of Chemistry (RSC)
Date: 2009
DOI: 10.1039/B912942A
Abstract: The presence of Pt(II) allows pre-organisation of 4,4'-dicarboxamidoindole-2,2'-bipyridine, enhancing anion affinity with the resulting complex displaying selectivity for dihydrogen phosphate in DMSO-d6-0.5% water. Moreover the Pt(II) complex behaves as a colorimetic sensor for fluoride.
Structural systematics of anion–receptor complexes: insights from electron-density distributions
Publisher: International Union of Crystallography (IUCr)
Date: 25-08-2013
Synthesis and electrochemical polymerization of calix[4]arenes containing N-substituted pyrrole moieties
Publisher: Elsevier BV
Date: 08-1995
Structural systematics of anion–receptor complexes: insights from electron-density distributions
Publisher: International Union of Crystallography (IUCr)
Date: 25-08-2013
Advances in applied supramolecular technologies
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D0CS00948B
Abstract: Supramolecular chemistry has successfully built a foundation of fundamental understanding. However, with this now achieved, we show how this area of chemistry is moving out of the laboratory towards successful commercialisation.
A Two-Dimensional Metallacycle Cross-Linked Switchable Polymer for Fast and Highly Efficient Phosphorylated Peptide Enrichment
Publisher: American Chemical Society (ACS)
Date: 27-05-2021
DOI: 10.1021/JACS.0C12904
4-Aminomethyl-phenylamino-bis-(3,4-dichloro-5-phenylcarbamoyl-1H-pyrrole-2-carboxamide) tetrabutylammonium salt
Publisher: International Union of Crystallography (IUCr)
Date: 09-04-2005
Conformational control of HCl co-transporter: imidazole functionalised isophthalamide vs. 2,6-dicarboxamidopyridine
Publisher: Royal Society of Chemistry (RSC)
Date: 2007
DOI: 10.1039/B703259E
Anion binding properties of 5,5′-dicarboxamido-dipyrrolylmethanes
Publisher: Royal Society of Chemistry (RSC)
Date: 2004
DOI: 10.1039/B409115A
Lipophilic balance – a new design principle for transmembrane anion carriers
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3SC52962B
Hydroquinone-Based Anion Receptors for Redox-Switchable Chloride Binding
Publisher: MDPI AG
Date: 11-07-2019
Abstract: A series of chloride receptors has been synthesized containing an amide hydrogen bonding site and a hydroquinone motif. It was anticipated that oxidation of the hydroquinone unit to quinone would greatly the diminish chloride binding affinity of these receptors. A conformational switch is promoted in the quinone form through the formation of an intramolecular hydrogen bond between the amide and the quinone carbonyl, which blocks the amide binding site. The reversibility of this oxidation process highlighted the potential of these systems for use as redox-switchable receptors. 1H-NMR binding studies confirmed stronger binding capabilities of the hydroquinone form compared to the quinone however, X-ray crystal structures of the free hydroquinone receptors revealed the presence of an analogous inhibiting intramolecular hydrogen bond in this state of the receptor. Binding studies also revealed interesting and contrasting trends in chloride affinity when comparing the two switch states, which is dictated by a secondary interaction in the binding mode between the amide carbonyl and the hydroquinone/quinone couple. Additionally, the electrochemical properties of the systems have been explored using cyclic voltammetry and it was observed that the reduction potential of the system was directly related to the expected strength of the internal hydrogen bond.
Anion Complexation Properties of Thiophene-2,4- and -2,5-biscarboxamides
Publisher: Institute of Organic Chemistry & Biochemistry
Date: 2004
DOI: 10.1135/CCCC20041301
Abstract: Thiophene-2,4- and -2,5-biscarboxamides have been synthesised and shown to act as anion receptors in DMSO- d 6 /water solution. The crystal structure of the fluoride complex of a N , N' -diphenylthiophene-2,5-biscarboxamide derivative has been solved and reveals the involvement of the thiophene CH protons in anion complexation in the solid state.
Transmembrane transport by platinum-based metal-organic anionophores
Publisher: American Chemical Society (ACS)
Date: 18-07-2023
DOI: 10.26434/CHEMRXIV-2023-BHZJB
Abstract: A series of Pt(II) metal complexes with urea-appended isoquinoline ligands act as efficient transmembrane chloride transporters and operate via classical hydrogen bonding interactions rather than ligand exchange. A number of the complexes exhibited potent transmembrane chloride transport activity.
Anion-triggered electrodeposition in ferrocene-functionalised ortho-phenylenediamine-based receptors
Publisher: Royal Society of Chemistry (RSC)
Date: 2008
DOI: 10.1039/B715125J
Fluorescent transmembrane anion transporters: shedding light on anionophoric activity in cells
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6SC01643J
Abstract: A series of fluorescent anion transporters have been synthesised and their anion transport properties and interactions with cancer cell lines studied.
A linear rod-packing coordination polymer constructed from a non-linear dicarboxylate and the [Zn4O]6+ cluster
Publisher: Informa UK Limited
Date: 02-08-2013
Confirmation of a ‘cleft-mode’ of binding in a 2,5-diamidopyrrole anion receptor in the solid state
Publisher: Elsevier BV
Date: 09-2002
Dynamic Covalent Transport of Amino Acids across Lipid Bilayers
Publisher: American Chemical Society (ACS)
Date: 27-01-2015
DOI: 10.1021/JA510063N
Abstract: We report a dynamic covalent approach to transmembrane transport of amino acids by the formation of a three-component assembly. A mixture of a squaramide and a lipophilic and electrophilic aldehyde is shown to synergistically transport highly polar glycine (Gly) across vesicle membranes. The transport was investigated by a (13)C NMR assay, an osmotic response assay, a newly developed fluorescence assay suitable for measuring Gly influx, and other fluorescence assays for leakage and pH change. The transport is proposed to occur via a hydrogen-bonded anionic glycine hemiaminal/imine, accompanied by transport of OH(-) in the opposite direction. Several control experiments support the role of hemiaminal/imine in the observed facilitated Gly transport. Proton NMR studies of a biphasic system show the presence of both the hemiaminal and imine formed between Gly and an aldehyde. Interestingly, the synergistic effect has also been observed for sarcosine, which can form hemiaminals but not imines. The results demonstrate the potential of hemiaminal formation for the facilitated transport of substrates containing primary and secondary amino groups.
Anion coordination and anion-directed assembly: highlights from 1997 and 1998
Publisher: Elsevier BV
Date: 04-2000
Anion−Anion Assembly: A New Class of Anionic Supramolecular Polymer Containing 3,4-Dichloro-2,5-diamido-substituted Pyrrole Anion Dimers
Publisher: American Chemical Society (ACS)
Date: 29-08-2002
DOI: 10.1021/JA027118V
Abstract: Two molecules containing two 2,5-diamido,3,4-dichloropyrrole units linked via 1,3- or 1,4-substituted benzene rings have been synthesized. The pyrrole groups in these compounds deprotonate in the presence of tetrabutylammonium fluoride and form pyrrole anion dimers via NH...N- hydrogen bonds. This dimerization process results in the formation of polyanionic chains linked via an unusual "orthogonal" hydrogen-bonding array.
Pendant arm pyrrolic amide cleft anion receptors
Publisher: Royal Society of Chemistry (RSC)
Date: 19-08-2002
DOI: 10.1039/B204295A
Abstract: The propensity of amine, ammonium and amide pendant arm 2,5-diamidopyrrole derivatives to act as anion receptors has been investigated the anion-coordination ability of these species has been determined by 1H NMR titration techniques revealing a marked selectivity of the amine functionalised receptor for hydrogen sulfate anions.
The influence of stereochemistry on anion binding and transport
Publisher: Informa UK Limited
Date: 07-2013
Titelbild: Voltage‐Switchable HCl Transport Enabled by Lipid Headgroup–Transporter Interactions (Angew. Chem. 42/2019)
Publisher: Wiley
Date: 13-09-2019
Cooperative Binding of Calix[4]pyrrole–Anion Complexes and Alkylammonium Cations in Halogenated Solvents
Publisher: Wiley
Date: 09-2008
Abstract: Calix[4]pyrrole-chloride interactions are affected not only by the choice of countercation in halogenated solvents, but show a specific dependence on the way in which these cations are bound within the electron rich, bowl-like calix[4]pyrrole cavity formed upon chloride anion complexation. In dichloromethane, the affinities of simple meso-octamethylcalix[4]pyrrole (1) for methyl-, ethyl-, and n-butylammonium chlorides are on the order of 10(5), 10(4), and 10(2) M(-1), respectively, as determined from isothermal titration calorimetry (ITC) analyses. These cation-dependent anion affinity effects, while clearly evident, are less pronounced in other halogenated solvents, such as 1,2-dichloroethane. Support for the proposed cation complexation selectivity is provided by solid state X-ray crystallographic analyses.
Controlling microenvironments and modifying anion binding selectivities using core functionalised hyperbranched polymers
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6CC02731H
Abstract: An isophthalamide anion binding site has been incorporated into hyperbranched polymers resulting in a change in the selectivity of the receptor from chloride to bromide.
Fatty Acid Fueled Transmembrane Chloride Transport
Publisher: American Chemical Society (ACS)
Date: 25-02-2019
DOI: 10.26434/CHEMRXIV.6823352.V2
Abstract: We report an ex le of the use of fatty acids to drive chloride transport by creating a pH gradient across a vesicular lipid bilayer membrane. Addition of an unselective squaramide-based chloride transporter (which transports both H + and Cl - ) facilitates the transport of HCl from the vesicle (driven by the pH gradient) so creating a chloride gradient. Addition of further aliquots of fatty acid ‘fuel’ can initiate further transport of chloride out of the vesicle by re-establishing the pH gradient. This is an ex le of a prototypical chloride pumping system.
Tetraurea Macrocycles: Aggregation-Driven Binding of Chloride in Aqueous Solutions
Publisher: Elsevier BV
Date: 05-2019
Diester-calix[4]arenediquinone complexation and electrochemical recognition of group 1 and 2, ammonium and alkyl ammonium guest cations.
Publisher: Elsevier BV
Date: 1994
Anion Receptors Based on Organic Frameworks: Recent Advances
Publisher: Springer International Publishing
Date: 2015
DOI: 10.1007/430_2015_174
Structure–Activity Relationships in Tripodal Transmembrane Anion Transporters: The Effect of Fluorination
Publisher: American Chemical Society (ACS)
Date: 16-08-2011
DOI: 10.1021/JA205884Y
Transmembrane Fluoride Transport: Direct Measurement and Selectivity Studies
Publisher: American Chemical Society (ACS)
Date: 07-12-2016
DOI: 10.1021/JACS.6B10694
Abstract: Fluoride has been overlooked as a target in the development of synthetic anion transporters despite natural fluoride transport channels being recently discovered. In this paper we report the direct measurement of fluoride transport across lipid bilayers facilitated by a series of strapped calix[4]pyrroles and show that these compounds facilitate transport via an electrogenic mechanism (determined using valinomycin and monensin coupled transport assays and an additional osmotic response assay). An HPTS transport assay was used to quantify this electrogenic process and assess the interference of naturally occurring fatty acids with the transport process and Cl
A biaryl cross-coupling strategy for functionalisation of benzocrown ethers
Publisher: Royal Society of Chemistry (RSC)
Date: 2007
DOI: 10.1039/B709861H
Abstract: Preparation of (di)benzocrown-substituted aryl-zinc or -boron reagents and their palladium-catalysed cross-coupling with functionalised aryl halides is described for convenient synthesis of novel crown ether systems.
Correction: Substituent interference on supramolecular assembly in urea gelators: synthesis, structure prediction and NMR
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6SM90091G
Abstract: Correction for 'Substituent interference on supramolecular assembly in urea gelators: synthesis, structure prediction and NMR' by Francesca Piana et al., Soft Matter, 2016, 12, 4034-4043.
Bis-cation salt complexation by meso-octamethylcalix[4]pyrrole: linking complexes in solution and in the solid state
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/B916113A
Ionic liquid–calix[4]pyrrole complexes: pyridinium inclusion in the calixpyrrole cup
Publisher: Royal Society of Chemistry (RSC)
Date: 2006
DOI: 10.1039/B600251J
Measuring anion binding at biomembrane interfaces
Publisher: American Chemical Society (ACS)
Date: 11-01-2022
DOI: 10.26434/CHEMRXIV-2021-6W803-V3
Abstract: Understanding non-covalent molecular recognition events at biomembrane interfaces is important in biological, medicinal, and materials chemistry research.1 Despite the crucial regulatory roles of anion binding/transport processes at biomembranes, no information is available regarding how strongly anions can bind to naturally occurring or synthetic receptors in lipid bilayer environments compared to their well-established behaviour in solutions.2 To bridge this knowledge gap, we synthesised a flat macrocycle that possesses a record aqueous SO42– affinity among neutral receptors and exploited its unique fluorescence response at interfaces. We show that the determinants of anion binding are extraordinarily different in organic solvents and in lipid bilayers. The high charge density of dihydrogen phosphate and chloride ions prevails in DMSO, however in lipids they fail to bind the macrocycle. Perchlorate and iodide hardly bind in DMSO but show significant affinities for the macrocycle in lipids. Our results demonstrate a surprisingly great advantage of large, charge-diffuse anions to bind to a lipid-embedded synthetic receptor mainly attributed to their higher polarisabilities and deeper penetration into the bilayer, beyond the common knowledge of dehydration energy-governed selectivity. The elucidation of these principles enhances our understanding of biological anion recognition functions in membranes and guides the design of ionophores and molecular machines operating at biomembrane interfaces.
2019 Sessler Early Career Researcher Prize
Publisher: Informa UK Limited
Date: 02-09-2019
Prospects and Challenges in Anion Recognition and Transport
Publisher: Elsevier BV
Date: 06-2020
12 Supramolecular chemistry
Publisher: Royal Society of Chemistry (RSC)
Date: 2002
DOI: 10.1039/B201510M
Towards the Discrimination of Carboxylates by Hydrogen‐Bond Donor Anion Receptors
Publisher: Wiley
Date: 13-02-2015
Abstract: The binding constants (log Kass ) of small synthetic receptor molecules based on indolocarbazole, carbazole, indole, urea and some others, as well as their combinations were measured for small carboxylate anions of different basicity, hydrophilicity and steric demands, that is, trimethylacetate, acetate, benzoate and lactate, in 0.5 % H2 O/[D6 ]DMSO by using the relative NMR-based measurement method. As a result, four separate binding affinity scales (ladders) including thirty-eight receptors were obtained with the scales anchored to indolocarbazole. The results indicate that the binding strength is largely, but not fully, determined by the strength of the primary hydrogen-bonding interaction. The latter in turn is largely determined by the basicity of the anion. The higher is the basicity of the anion the stronger in general is the binding, leading to the approximate order of increasing binding strength, lactate<benzoate<acetate≤trimethylacetate, which holds with all investigated receptors. Nevertheless, there are a number of occasions when the binding order changes with changing of the carboxylate anion, sometimes quite substantially. Principal component analysis (PCA) reveals that this is primarily connected to preferential binding of trimethylacetate, supposedly caused by an additional hydrophobic/solvophobic interaction. These findings enable making better predictions, which receptor framework or cavity is best suited for carboxylate anions in receptor design.
Fluoride-Selective Binding in a New Deep Cavity Calix[4]pyrrole: Experiment and Theory
Publisher: American Chemical Society (ACS)
Date: 28-06-2002
DOI: 10.1021/JA025572T
Abstract: A new "super-extended cavity" tetraacetylcalix[4]pyrrole derivative was synthesized and characterized, and X-ray crystal structures of complexes bound to fluoride and acetonitrile were obtained. The binding behavior of this receptor was investigated by NMR titration, and the complex was found to exclusively bind fluoride ions in DMSO-d(6). This unusual binding behavior was investigated by Monte Carlo free energy perturbation simulations and Poisson calculations, and the ion specificity was seen to result from the favorable electrostatic interactions that the fluoride gains by sitting lower in the phenolic cavity of the receptor. The effect of water present in the DMSO on the calculated free energies of binding was also investigated. Owing to the use of a saturated ion solution, the effect of contaminating water is small in this case however, it has the potential to be very significant at lower ion concentrations. Finally, the adaptive umbrella WHAM protocol was investigated and optimized for use in binding free energy calculations, and its efficiency was compared to that of the free energy perturbation calculations adaptive umbrella WHAM was found to be approximately two times more efficient. In addition, structural evidence demonstrates that the protocol explores a wider conformational range than free energy perturbation and should therefore be the method of choice. This paper represents the first complete application of this methodology to "alchemical" changes.
2-Amidopyrroles and 2,5-Diamidopyrroles as Simple Anion Binding Agents
Publisher: American Chemical Society (ACS)
Date: 19-10-2001
DOI: 10.1021/JO016020G
Abstract: Four new 2-amidopyrroles and 2,5-diamidopyrroles have been synthesized and their anion complexation properties investigated. The crystal structures of these receptors have been elucidated and reveal hydrogen bonding in the solid state leading to dimer and network formation. Selectivity for oxo-anions has been demonstrated by (1)H NMR titration techniques.
Advances in fluorescent and colorimetric sensors for anionic species
Publisher: Elsevier BV
Date: 2021
Towards predictable transmembrane transport: QSAR analysis of anion binding and transport
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3SC51023A
Anion receptor chemistry: highlights from 2008 and 2009
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/C001871F
Abstract: This critical review covers advances in anion complexation in the year 2008 and 2009. The review discusses anion receptors that employ hydrogen bond donors (both NH and CH), electrostatic interactions, Lewis acidic centres and combinations of these three types of binding interaction to complex anions. Additionally nanotechnological approaches to anion sensing in aqueous solution, lipid bilayer transporters and recent work on the use of anions to drive conformational change are highlighted (130 references).
Tripodal molecules for the promotion of phosphoester hydrolysis
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4CC00333K
Abstract: A series of low molecular weight tripodal amide/histidine-containing compounds have been synthesised and shown to increase the rate of bis-( p -nitrophenyl) phosphate (BNPP) and soman (GD) breakdown in buffered aqueous solution.
9 Supramolecular chemistry
Publisher: Royal Society of Chemistry (RSC)
Date: 2004
DOI: 10.1039/B401746N
NH vs. CH hydrogen bond formation in metal–organic anion receptors containing pyrrolylpyridine ligands
Publisher: Royal Society of Chemistry (RSC)
Date: 2005
DOI: 10.1039/B510506D
Abstract: Anion complexation studies on a series of platinum(II) tetrakis(pyrrolylpyridine) salts demonstrate the importance of CH-anion hydrogen bonds in coordinating anionic guests in solution and the solid-state.
A synthetic ion transporter that disrupts autophagy and induces apoptosis by perturbing cellular chloride concentrations
Publisher: Springer Science and Business Media LLC
Date: 30-01-2017
DOI: 10.1038/NCHEM.2706
Preface: supramolecular chemistry of anionic species themed issue
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/C0CS90020F
1,3‐Diindolylureas and 1,3‐Diindolylthioureas: Anion Complexation Studies in Solution and the Solid State
Publisher: Wiley
Date: 10-11-2008
Abstract: 1,3-Diindolylureas and thioureas have been synthesised and their anion complexation properties in solution studied. Whilst diindolylthioureas showed only moderate affinities and selectivities, diindolylureas show remarkably high affinity for dihydrogen phosphate in solution for an acyclic, neutral receptor in water/[D(6)]DMSO mixtures. These easy-to-make compounds adopt relatively planar conformations in the solid-state and are able to donate four hydrogen bonds and yet not fill the coordination sphere of carbonate or phosphate, allowing two or three receptors to bind to each anion in the solid-state.
Using small molecules to facilitate exchange of bicarbonate and chloride anions across liposomal membranes
Publisher: Springer Science and Business Media LLC
Date: 19-04-2009
DOI: 10.1038/NCHEM.178
Abstract: Bicarbonate is involved in a wide range of biological processes, which include respiration, regulation of intracellular pH and fertilization. In this study we use a combination of NMR spectroscopy and ion-selective electrode techniques to show that the natural product prodigiosin, a tripyrrolic molecule produced by microorganisms such as Streptomyces and Serratia, facilitates chloride/bicarbonate exchange (antiport) across liposomal membranes. Higher concentrations of simple synthetic molecules based on a 4,6-dihydroxyisophthalamide core are also shown to facilitate this antiport process. Although it is well known that proteins regulate Cl(-)/HCO(3)(-) exchange in cells, these results suggest that small molecules may also be able to regulate the concentration of these anions in biological systems.
Methyl 5-methyl-3,4-diphenyl-1H-pyrrole-2-carboxylate
Publisher: International Union of Crystallography (IUCr)
Date: 30-11-2001
Advances in anion transport and supramolecular medicinal chemistry
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/C9CS00662A
Abstract: The development of discrete molecular carriers for anions and supramolecular anion channels are reviewed followed by an overview of the use of these systems in biological systems as putative treatments for diseases such as cystic fibrosis and cancer.
1,4-Phenylene-bis-(3,4-dichloro-5-phenylcarbamoyl-1H-pyrrole-2-carboxamide) bis(tetrabutylammonium chloride) acetonitrile disolvate
Publisher: International Union of Crystallography (IUCr)
Date: 09-04-2005
Anion Receptor Chemistry
Publisher: Elsevier BV
Date: 09-2016
A potent fluorescent transmembrane HCl transporter perturbs cellular pH and promotes cancer cell death
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3OB00128H
Abstract: A series of fluorescent coumarin-based bis-ureas have been synthesised. These compounds show strong HCl cotransport properties in model vesicle systems. Cellular localisation studies show that cytotoxic compound 4 localises in lysosomes and perturbs cellular pH.
Metal, ammonium and alkyl ammonium cation recognition by a novel calix[4]arenediquinone crown ether
Publisher: Royal Society of Chemistry (RSC)
Date: 1994
DOI: 10.1039/C39940002207
Synthetic ion transporters can induce apoptosis by facilitating chloride anion transport into cells
Publisher: Springer Science and Business Media LLC
Date: 11-08-2014
DOI: 10.1038/NCHEM.2021
Abstract: Anion transporters based on small molecules have received attention as therapeutic agents because of their potential to disrupt cellular ion homeostasis. However, a direct correlation between a change in cellular chloride anion concentration and cytotoxicity has not been established for synthetic ion carriers. Here we show that two pyridine diamide-strapped calix[4]pyrroles induce coupled chloride anion and sodium cation transport in both liposomal models and cells, and promote cell death by increasing intracellular chloride and sodium ion concentrations. Removing either ion from the extracellular media or blocking natural sodium channels with amiloride prevents this effect. Cell experiments show that the ion transporters induce the sodium chloride influx, which leads to an increased concentration of reactive oxygen species, release of cytochrome c from the mitochondria and apoptosis via caspase activation. However, they do not activate the caspase-independent apoptotic pathway associated with the apoptosis-inducing factor. Ion transporters, therefore, represent an attractive approach for regulating cellular processes that are normally controlled tightly by homeostasis.
Carbazole-based bis-ureas and thioureas as electroneutral anion transporters
Publisher: Informa UK Limited
Date: 03-04-2021
Imide linked ‘4 + 4’ macrocycles formed by condensation of isophthaloyl dichloride and tetra- or penta-fluoroaniline
Publisher: Royal Society of Chemistry (RSC)
Date: 2004
DOI: 10.1039/B401614A
Stimuli‐Responsive Cycloaurated “OFF‐ON” Switchable Anion Transporters
Publisher: Wiley
Date: 11-08-2020
Abstract: Anion transporters have shown potential application as anti‐cancer agents that function by disrupting homeostasis and triggering cell death. In this research article we report switchable anion transport by gold complexes of anion transporters that are “switched on” in situ in the presence of the reducing agent GSH by decomplexation of gold. GSH is found in higher concentrations in tumors than in healthy tissue and hence this approach offers a strategy to target these systems to tumors.
Supramolecular Transmembrane Anion Transport: New Assays and Insights
Publisher: American Chemical Society (ACS)
Date: 31-07-2018
DOI: 10.1021/ACS.ACCOUNTS.8B00264
Abstract: Transmembrane anion transport has been the focus of a number of supramolecular chemistry research groups for a number of years. Much of this research is driven by the biological relevance of anion transport and the search to find new treatments for diseases such as cystic fibrosis, which is caused by genetic problems leading to faulty cystic fibrosis transmembrane conductance regulator (CFTR) channels, which in turn lead to reduced chloride and bicarbonate transport through epithelial cell membranes. Considerable effort has been devoted to the development of new transporters, and our group along with others have been searching for combinations of organic scaffolds and anion binding groups that produce highly effective transporters that work at low concentration. These compounds may be used in the future as "channel replacement therapies", restoring the flux of anions through epithelial cell membranes and ameliorating the symptoms of cystic fibrosis. Less effort has been put into gaining a fundamental understanding of anion transport processes. Over the last 3 years, our group has developed a number of new transport assays that allow anion transport mechanisms to be determined. This Account covers the latest developments in this area, providing a concise review of the new techniques we can use to study anion transport processes in idually without resorting to measurement of exchange processes and the new insights that these assays provide. The Account provides an overview of the effects of anion transporters on cells and an explanation of why many systems perturb pH gradients within cells in addition to transporting chloride. We discuss assays to determine whether anionophores facilitate chloride or HCl transport and how this latter assay can be modified to determine chloride versus proton selectivity in small-molecule anion receptors. We show how molecular design can be used to produce receptors that are capable of transporting chloride without perturbing pH gradients. We cover the role that anion transporters in the presence of fatty acids play in dissipating pH gradients across lipid bilayer membranes and the effect that this process has on chloride-selective transport. We also discuss how coupling of anion transport to cation transport by natural cationophores can be used to determine whether anion transport is electrogenic or electroneutral. In addition, we compare these new assays to the previously used chloride/nitrate exchange assay and show how this exchange assay can underestimate the chloride transport ability of certain receptors that are rate-limited by nitrate transport.
Supramolecular chemistry: defined
Publisher: Informa UK Limited
Date: 12-02-2015
Calix[4]pyrroles: New Solid-Phase HPLC Supports for the Separation of Anions
Publisher: Wiley
Date: 15-06-1998
DOI: 10.1002/(SICI)1521-3765(19980615)4:6<1095::AID-CHEM1095>3.0.CO;2-1
Anion receptor chemistry: highlights from 1999
Publisher: Elsevier BV
Date: 03-2001
New Ionophoric Calix[4]diquinones: Coordination Chemistry, Electrochemistry, and X-ray Crystal Structures
Publisher: American Chemical Society (ACS)
Date: 12-1997
DOI: 10.1021/IC9704851
Abstract: A new library of ionophoric p-tert-butylcalix[4]diquinones containing ester (1), primary, secondary, and tertiary amide (2-4), and crown ether (5) substituents has been synthesized by treatment of the respective 1,3-bis-substituted p-tert-butylcalix[4]arene with Tl(OCOCF(3))(3) in trifluoroacetic acid. The structures of the free ligands 1 and 2, a p-tert-butylcalix[4]diquinone bridged at the lower rim by two linked veratrole groups (7), and a previously synthesized p-tert-butylcalix[4]diquinone bis(methyl ether) species (8) have been elucidated by X-ray crystallography. The X-ray crystal structures of 1-Sr(ClO(4))(2), 1-KClO(4), 2-NaClO(4), 4-n-BuNH(3)BF(4), 5-NaOCOCF(3), and 5-KPF(6) demonstrate that these complexes adopt the cone conformation in the solid state. Interestingly, cation-quinone oxygen atom coordination occurs at both the upper and lower rim of 2-NaClO(4) and 4-n-BuNH(3)BF(4). Solution coordination properties have been studied by both (1)H NMR and UV/vis techniques. The electrochemical properties of the "acyclic" p-tert-butylcalixdiquinones 1, 4, and 8 and their complexes have been studied using cyclic and square wave voltammetric techniques. The reduction potentials of the group 1 or 2 metal, ammonium, and alkylammonium complexes are significantly anodically shifted with respect to that of the free ligand. Addition of cations to electrochemical solutions of a p-tert-butylcalixdiquinone-crown-5 compound (5) caused large anodic shifts (by up to 555 mV in the presence of Ba(2+)) in a manner similar to that of the acyclic species.
Anion transport by ortho-phenylene bis-ureas across cell and vesicle membranes
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7OB02787G
Abstract: These simple bis-ureas are found to be powerful anionophores in synthetic vesicles, and also in a live cell assay employing yellow fluorescent protein.
Structurally simple lipid bilayer transport agents for chloride and bicarbonate
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C0SC00503G
An anion-binding fluorinated alcohol isophthalamide isostere
Publisher: Royal Society of Chemistry (RSC)
Date: 06-01-2014
DOI: 10.1039/C3RA45956J
High‐Affinity Anion Binding by Steroidal Squaramide Receptors
Publisher: Wiley
Date: 17-02-2015
ortho-Phenylenediamine bis-urea–carboxylate: a new reliable supramolecular synthon
Publisher: Royal Society of Chemistry (RSC)
Date: 2005
DOI: 10.1039/B511932D
Tripodal transmembrane transporters for bicarbonate
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/C0CC01684E
Fluoride binding by an anionic receptor: tuning the acidity of amide NH groups for basic anion hydrogen bonding and recognition
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C8CC09962F
Abstract: Here we report the first family of bis-amide receptors able to bind fluoride in their anionic form.
Neutral 1,3‐Diindolylureas for Nerve Agent Remediation
Publisher: Wiley
Date: 23-12-2012
Tetrabutylammoniummeso-octamethylcalix[4]pyrrole fluoride dichloromethane solvate
Publisher: International Union of Crystallography (IUCr)
Date: 10-08-2001
Acridinone-based anion transporters
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1OB01545A
Abstract: The acridinone 1,9-bis(thio)urea scaffold was repurposed for application in anion transport by appending a variety of electron-withdrawing groups to the peripheral phenyl moieties. High levels of activity were achieved which facilitated strictly electroneutral transport.
Crown ether-thiourea conjugates as ion transporters
Publisher: Springer Science and Business Media LLC
Date: 15-05-2021
Organophosphorus chemical warfare agent simulant DMMP promotes structural reinforcement of urea-based chiral supramolecular gels
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4RA15241G
Abstract: The addition of a certain amount of organophosphorus chemical warfare agent simulant DMMP promotes strengthening of the urea-based supramolecular gel structure.
Fluorescent carbazolylurea anion receptors
Publisher: Royal Society of Chemistry (RSC)
Date: 2009
DOI: 10.1039/B900178F
Abstract: A series of fluorescent carbazolylurea base anion receptors have been synthesised that show a high affinity for oxo-anions (particularly bicarbonate and acetate). The fluorescence of dicarbazolylurea (1) is quenched upon addition of benzoate anions in DMSO-0.5% water.
Applications of Supramolecular Anion Recognition
Publisher: American Chemical Society (ACS)
Date: 21-05-2015
Modified Calix[4]pyrroles
Publisher: American Chemical Society (ACS)
Date: 18-08-2000
DOI: 10.1021/IE000102Y
Anion complexation, transport and structural studies of a series of bis-methylurea compounds
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4DT02893G
Abstract: A new family of bis-methylureas have been synthesised and their ability to bind anions both in solution and in the solid state and to transport them through lipid membrane have been studied.
Anion transport and binding properties of N N′-(phenylmethylene)dibenzamide based receptors
Publisher: Informa UK Limited
Date: 27-04-2015
Service crystallography – right tools for the challenge
Publisher: International Union of Crystallography (IUCr)
Date: 25-08-2013
Supramolecular Chemistry—Introducing the latest web themed issue
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C1CC90048J
Highlights from the Faraday Discussion on Artificial Water Channels, Glasgow, UK
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9CC90112D
Abstract: The Faraday Discussion on Artificial Water Channels was the first of its kind organized on a recently conceived field and was held from 25–27 June 2018 at the Technology & Innovation Centre at the University of Strathclyde.
Editorial: a methods article
Publisher: Informa UK Limited
Date: 20-04-2019
Fluorinated tetrapodal anion transporters
Publisher: Elsevier BV
Date: 02-2023
Full elucidation of the transmembrane anion transport mechanism of squaramides using: In silico investigations
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8CP02576B
Abstract: The anion carrier mechanism promoted by squaramide-based molecules has been elucidated by molecular dynamics and chloride efflux studies.
Perenosins: a new class of anion transporter with anti-cancer activity
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6OB00002A
Abstract: A new class of anion transporter named ‘perenosins’ consisting of a pyrrole linked through an imine to either an indole, benzimidazole or indazole is reported.
Fatty Acid-Activated Proton Transport by Bisaryl Anion Transporters Depolarises Mitochondria and Reduces the Viability of MDA-MB-231 Breast Cancer Cells
Publisher: MDPI AG
Date: 31-07-2023
DOI: 10.3390/BIOM13081202
Abstract: In respiring mitochondria, the proton gradient across the inner mitochondrial membrane is used to drive ATP production. Mitochondrial uncouplers, which are typically weak acid protonophores, can disrupt this process to induce mitochondrial dysfunction and apoptosis in cancer cells. We have shown that bisaryl urea-based anion transporters can also mediate mitochondrial uncoupling through a novel fatty acid-activated proton transport mechanism, where the bisaryl urea promotes the transbilayer movement of deprotonated fatty acids and proton transport. In this paper, we investigated the impact of replacing the urea group with squaramide, amide and diurea anion binding motifs. Bisaryl squaramides were found to depolarise mitochondria and reduce MDA-MB-231 breast cancer cell viability to similar extents as their urea counterpart. Bisaryl amides and diureas were less active and required higher concentrations to produce these effects. For all scaffolds, the substitution of the bisaryl rings with lipophilic electron-withdrawing groups was required for activity. An investigation of the proton transport mechanism in vesicles showed that active compounds participate in fatty acid-activated proton transport, except for a squaramide analogue, which was sufficiently acidic to act as a classical protonophore and transport protons in the absence of free fatty acids.
Supramolecular chemistry anniversary
Publisher: Royal Society of Chemistry (RSC)
Date: 2007
DOI: 10.1039/B617780H
Structures of potassium encapsulated within the 1,3-alternate conformation of calix[4]arenes
Publisher: Royal Society of Chemistry (RSC)
Date: 1994
DOI: 10.1039/DT9940003479
Anion receptor chemistry: highlights from 2010
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C1CS15257B
Abstract: This critical review covers advances in anion complexation in the year 2010. The review covers both organic and inorganic systems and also highlights the applications to which anion receptors can be applied such as sensing, anion transport, control of molecular motion and gelation (179 references).
Fluorescent squaramides as anion receptors and transmembrane anion transporters
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7CC08706C
Abstract: Squaramides functionalised with a naphthalimide fluorophore as effective fluorescent anion transporters.
Voltage‐Switchable HCl Transport Enabled by Lipid Headgroup–Transporter Interactions
Publisher: Wiley
Date: 30-08-2019
Abstract: Synthetic anion transporters that facilitate transmembrane H
Amidopyrroles: from anion receptors to membrane transport agents
Publisher: Royal Society of Chemistry (RSC)
Date: 2005
DOI: 10.1039/B504596G
Abstract: Amidopyrroles have been employed in a variety of anion receptors and sensors. 2,5-Bisamidopyrroles show selective oxo-anion complexation properties in organic solution whilst bis-amides containing dipyrrolylmethane groups form strong complexes with dihydrogen phosphate anions in mixtures of DMSO-d6 and water. Deprotonation of the 2,5-bisamidopyrrole unit can lead to interesting solid-state structures including the formation of orthogonal hydrogen bonded dimers. Amidopyrrole groups have also been employed in receptors for ion-pairs and in membrane transport agents for HCl.
New Bis- and Tris-Ferrocenoyl and Tris-Benzoyl Lower-rim Substituted Calix[5]arene Esters: Synthesis, Electrochemistry and X-ray Crystal Structures
Publisher: Informa UK Limited
Date: 08-1996
2,7-Functionalized Indoles as Receptors for Anions
Publisher: American Chemical Society (ACS)
Date: 16-10-2007
DOI: 10.1021/JO701702P
Abstract: A series of 2,7-functionalized indoles have been synthesized with appended amide and/or urea or thiourea groups. Anion complexation studies show a marked difference in the mode of interaction of carboxylates with indole-ureas vs indole-amides.
Aromatic isophthalamides aggregate in lipid bilayers: evidence for a cooperative transport mechanism
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4OB02631D
Abstract: The synthesis and anion transport properties of a series of aromatic transmembrane anion transporters based on an isophthalamide scaffold are reported.
A tripodal tris-selenourea anion transporter matches the activity of its thio- analogue but shows distinct selectivity
Publisher: Informa UK Limited
Date: 08-02-2018
‘Twisted’ isophthalamide analogues
Publisher: Royal Society of Chemistry (RSC)
Date: 2005
DOI: 10.1039/B413654C
Abstract: Steric interactions in 1,3-dicarboxamidoanthraquinones have been employed to 'twist' isophthalamide-like anion binding sites the crystal structure of the fluoride complex of a bis-3,5-dichlorophenylamide derivative shows the receptor acting as a 'hydrogen-bonding corner' in a '2 + 2' fluoride containing molecular box.
Systematic experimental charge density analysis of anion receptor complexes
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3CP54858A
Abstract: The first systematic electronic resolution study of a series of urea-based anion receptor complexes is presented and shows the binding strength to be greater for more basic anion–receptor pairs in the solid state.
Conformational Control of Selectivity and Stability in Hybrid Amide/Urea Macrocycles
Publisher: Wiley
Date: 03-04-2007
Abstract: The anion-binding properties of two similar hybrid amide/urea macrocycles containing either a 2,6-dicarboxamidophenyl or a 2,6-dicarboxamidopyridine group are compared. Significant differences in anion affinity and mode of interaction with anions are attributed to the presence of intramolecular hydrogen bonds in the pyridine system. In fact, remarkably, the phenyl macrocycle undergoes amide hydrolysis under neutral conditions in DMSO/water. The anion binding abilities of the receptors are compared to those of acyclic analogues of the macrocycles that show that the phenyl receptor behaves in a similar fashion to acyclic urea-containing receptors (i.e., showing little selectivity amongst oxo anions), whilst the pyridine-containing receptor shows a high affinity and selectivity for carboxylates.
Stimuli-Responsive Cycloaurated ‘OFF-ON’ Switchable Anion Transporters
Publisher: American Chemical Society (ACS)
Date: 05-05-2020
DOI: 10.26434/CHEMRXIV.12235880.V1
Abstract: Anion transporters have shown potential application as anti-cancer agents that function by disrupting homeostasis and triggering cell death. In this research article we report switchable anion transport by gold complexes of anion transporters that are ‘switched on’ in the presence of the reducing agent GSH by decomplexation of gold. GSH is found in higher concentrations in tumours than in healthy tissue and hence offers a strategy to target these systems to tumours.
Anion–Anion Proton Transfer in Hydrogen Bonded Complexes
Publisher: Wiley
Date: 22-02-2010
Abstract: Complexation of dihydrogen phosphate by an anion receptor containing six hydrogen bond donor groups has been shown to reduce the pK(a) of the bound anionic species to such an extent that addition of further aliquots of dihydrogen phosphate result in deprotonation of the bound species with the resultant formation of a monohydrogen phosphate receptor complex. X-ray crystallographic studies confirm monohydrogen phosphate complex formation in the solid state. In this way, this study explains the formation of complexes with unusual stoichiometries when investigating the binding of dihydrogenphosphate anion to hydrogen-bonding receptors.
Effects of calixarenes on the electrochemical reduction of buckminsterfullerene, C60
Publisher: Elsevier BV
Date: 07-1995
Stabilisation of alkylcarbamate anions using neutral hydrogen bond donors
Publisher: Elsevier BV
Date: 08-2009
Anion binding vs.sulfonamide deprotonation in functionalised ureas
Publisher: Royal Society of Chemistry (RSC)
Date: 2008
DOI: 10.1039/B713431B
Abstract: Sulfonamide groups, commonly used as neutral hydrogen bond donors in a wide variety of anion receptors, deprotonate upon addition of certain basic anionic guests in two simple functionalised ureas.
Tris-(2-aminoethyl)amine-based tripodal trisindolylureas: new receptors for sulphate
Publisher: Informa UK Limited
Date: 11-04-2012
Voltage‐Switchable HCl Transport Enabled by Lipid Headgroup–Transporter Interactions
Publisher: Wiley
Date: 30-08-2019
Biasing hydrogen bond donating host systems towards chemical warfare agent recognition
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6OB01210H
Abstract: Selectivity in hydrogen bond-driven recognition events is biased via electrostatic repulsion to favour complexation of neutral Chemical Warfare Agent over anionic guests.
pH-Regulated Nonelectrogenic Anion Transport by Phenylthiosemicarbazones
Publisher: American Chemical Society (ACS)
Date: 24-06-2016
DOI: 10.1021/JACS.6B04656
Abstract: Gated ion transport across biological membranes is an intrinsic process regulated by protein channels. Synthetic anion carriers (anionophores) have potential applications in biological research however, previously reported ex les are mostly nonspecific, capable of mediating both electrogenic and electroneutral (nonelectrogenic) transport processes. Here we show the transmembrane Cl(-) transport studies of synthetic phenylthiosemicarbazones mimicking the function of acid-sensing (proton-gated) ion channels. These anionophores have remarkable pH-switchable transport properties with up to 640-fold increase in transport efficacy on going from pH 7.2 to 4.0. This "gated" process is triggered by protonation of the imino nitrogen and concomitant conformational change of the anion-binding thiourea moiety from anti to syn. By using a combination of two cationophore-coupled transport assays, with either monensin or valinomycin, we have elucidated the fundamental transport mechanism of phenylthiosemicarbazones which is shown to be nonelectrogenic, inseparable H(+)/Cl(-) cotransport. This study demonstrates the first ex les of pH-switchable nonelectrogenic anion transporters.
Tunable transmembrane chloride transport by bis-indolylureas
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2SC20041D
Determinants of Ion-Transporter Cancer Cell Death
Publisher: Elsevier BV
Date: 08-2019
Aryl urea substituted fatty acids: a new class of protonophoric mitochondrial uncoupler that utilises a synthetic anion transporter
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0SC02777D
Abstract: A new mitochondrial uncoupler that forms membrane permeable dimers through interactions of remote acidic and anion receptor groups.
Thiourea isosteres as anion receptors and transmembrane transporters
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C1CC12439K
Abstract: Compounds containing cyanoguanidine and 3-amino-1,2,4-benzothiadiazine-1,1-dioxide have been studied as anion receptors and transporters. Significant affinity for oxo-anions was observed in organic solution and the receptors were found to function as transmembrane chloride/nitrate antiporters with transport rates enhanced in the presence of valinomycin-K(+) complex.
Substituent interference on supramolecular assembly in urea gelators: synthesis, structure prediction and NMR
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6SM00607H
Abstract: Eighteen N-aryl-N'-alkyl urea gelators were synthesised in order to understand the effect of head substituents on gelation performance. Minimum gelation concentration values obtained from gel formation studies were used to rank the compounds and revealed the remarkable performance of 4-methoxyphenyl urea gelator 15 in comparison to 4-nitrophenyl analogue 14, which could not be simply ascribed to substituent effects on the hydrogen bonding capabilities of the urea protons. Crystal structure prediction calculations indicated alternative low energy hydrogen bonding arrangements between the nitro group and urea protons in gelator 14, which were supported experimentally by NMR spectroscopy. As a consequence, it was possible to relate the observed differences to interference of the head substituents with the urea tape motif, disrupting the order of supramolecular packing. The combination of unbiased structure prediction calculations with NMR is proposed as a powerful approach to investigate the supramolecular arrangement in gel fibres and help understand the relationships between molecular structure and gel formation.
Electrochemical Recognition of Charged and Neutral Guest Species by Redox-active Receptor Molecules
Publisher: Elsevier
Date: 1999
Squaramides as Potent Transmembrane Anion Transporters
Publisher: Wiley
Date: 27-03-2012
Voltage-Switchable HCl Transporters: The Effect of Lipid Headgroup Binding
Publisher: American Chemical Society (ACS)
Date: 30-04-2019
DOI: 10.26434/CHEMRXIV.8051915.V1
Abstract: Synthetic anion transporters that facilitate transmembrane H + /Cl - symport (cotransport)have anti-cancer potential due to their ability to neutralize pH gradients and inhibit autophagy in cells. However, compared to the natural product prodigiosin, synthetic anion transporters have low-to-modest H + /Cl - symportactivity and their mechanism of action remains less well understood. We here report a chloride-selective tetraurea macrocycle that has a record-high H + /Cl - symportactivity similar to prodigiosin and most importantly demonstrates unprecedented voltage-switchable transport properties that is linked to the lack of uniport activity. By studying anion binding affinity and transport mechanisms of four other anion transporters, we show that the lack of uniport and the voltage-dependent H + /Cl - symport originate from strong binding to lipid phosphate headgroup that h ers the diffusion of the free transporters through the membranes, leading to an unusual H + /Cl - symport mechanism that involves only charged species. Our work provides important mechanistic insights into different classes of anion transporters and a new approach to achieve voltage-switchability in artificial membrane transport systems.
Acyclic Pseudopeptidic Hosts as Molecular Receptors and Transporters for Anions
Publisher: Wiley
Date: 03-07-2015
Back matter
Publisher: Royal Society of Chemistry (RSC)
Date: 2006
DOI: 10.1039/B517325F
NMR studies of anion-induced conformational changes in diindolylureas and diindolylthioureas
Publisher: Beilstein Institut
Date: 02-09-2011
DOI: 10.3762/BJOC.7.140
Abstract: The conformational properties of 1,3-diindolylureas and thioureas were studied by a combination of heteronuclear NMR spectroscopy and quantum mechanics calculations. NOE experiments showed that the anti–anti conformer along the C7–N7α bonds was predominant in DMSO- d 6 solution in the absence of anions. Anion-induced changes in the 1 H and 15 N chemical shifts confirm the weak binding of chloride anions with negligible conformational changes. Strong deshielding of ureido protons and moderate deshielding of indole NH was observed upon the addition of acetate, benzoate, bicarbonate and dihydrogen phosphate, which indicated that the predominant hydrogen bond interactions occurred at the urea donor groups. Binding of oxo-anions caused conformational changes along the C7–N7α bonds and the syn – syn conformer was preferred for anion–receptor complexes. The conformational changes upon anion binding are in good agreement with energetic preferences established by ab initio calculations.
Carboxylate complexation by 1,1′-(1,2-phenylene)bis(3-phenylurea) in solution and the solid state
Publisher: Royal Society of Chemistry (RSC)
Date: 2005
DOI: 10.1039/B508144K
Abstract: A simple bis-urea containing anion receptor, synthesised from ortho-phenylenediamine, has been shown to have excellent selectivity for carboxylates in solution, with a crystal structure elucidation of the benzoate complex showing four hydrogen bonds between the receptor and anion in the solid state.
Oligoether-strapped calix[4]pyrrole: An ion-pair receptor displaying cation-dependent chloride anion transport
Publisher: Wiley
Date: 02-2012
Towards conformationally dependent redox-responsive molecular switches. New polyferrocene bis benzo crown ether receptors
Publisher: Elsevier BV
Date: 03-1995
Fluorinated tripodal receptors for potentiometric chloride detection in biological fluids
Publisher: Elsevier BV
Date: 2018
DOI: 10.1016/J.BIOS.2017.07.001
Abstract: Fluorinated tripodal compounds were recently reported to be efficient transmembrane transporters for a series of inorganic anions. In particular, this class of receptors has been shown to be suitable for the effective complexation of chloride, nitrate, bicarbonate and sulfate anions via hydrogen bonding. The potentiometric properties of urea and thiourea-based fluorinated tripodal receptors are explored here for the first time, in light of the need for reliable sensors for chloride monitoring in undiluted biological fluids. The ion selective electrode (ISE) membranes with tren-based tris-urea bis(CF
Cyclic and Acyclic Amidopyrrole Containing Anion Receptors
Publisher: Springer-Verlag
Date: 2005
Measuring anion transport selectivity: a cautionary tale
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1CC01038G
Abstract: pH-dependent liposomal assays are often used to determine anion selectivity in transmembrane anion transport experiments. In this communication, we discuss the validity and limitations of these assays, and provide guidelines for their use to avoid misleading results.
Dissecting the chloride-nitrate anion transport assay
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7CC04912A
Abstract: The chloride/nitrate selectivity of anion transporters in both binding and membrane transport is examined revealing the limitations of chloride–nitrate anion exchange assay.
Benzimidazole-based anion receptors: tautomeric switching and selectivity
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C1OB06800H
Abstract: Tautomeric switching is observed in a series of benzimidazole-based anion receptors upon addition of basic anions. An N-methylbenzimidazole based receptor selectively interacts with dihydrogen phosphate over a variety of other putative anionic guests via a combination of donated and accepted hydrogen bonds.
Investigating the influence of steric hindrance on selective anion transport
Publisher: MDPI AG
Date: 02-04-2019
DOI: 10.3390/MOLECULES24071278
Abstract: A series of symmetrical and unsymmetrical alkyl tren based tris-thiourea anion transporters were synthesised and their anion binding and transport properties studied. Overall, increasing the steric bulk of the substituents resulted in improved chloride binding and transport abilities. Including a macrocycle in the scaffold enhanced the selectivity of chloride transport in the presence of fatty acids, by reducing the undesired H+ flux facilitated by fatty acid flip-flop. This study demonstrates the benefit of including enforced steric hindrance and encapsulation in the design of more selective anion receptors.
Squaramide-based synthetic chloride transporters activate TFEB but block autophagic flux
Publisher: Springer Science and Business Media LLC
Date: 11-03-2019
DOI: 10.1038/S41419-019-1474-8
Abstract: Cystic fibrosis is a disease caused by defective function of a chloride channel coupled to a blockade of autophagic flux. It has been proposed to use synthetic chloride transporters as pharmacological agents to compensate insufficient chloride fluxes. Here, we report that such chloride anionophores block autophagic flux in spite of the fact that they activate the pro-autophagic transcription factor EB (TFEB) coupled to the inhibition of the autophagy-suppressive mTORC1 kinase activity. Two synthetic chloride transporters ( SQ1 and SQ2 ) caused a partially TFEB-dependent relocation of the autophagic marker LC3 to the Golgi apparatus. Inhibition of TFEB activation using a calcium chelator or calcineurin inhibitors reduced the formation of LC3 puncta in cells, yet did not affect the cytotoxic action of SQ1 and SQ2 that could be observed after prolonged incubation. In conclusion, the squaramide-based synthetic chloride transporters studied in this work (which can also dissipate pH gradients) are probably not appropriate for the treatment of cystic fibrosis yet might be used for other indications such as cancer.
Back matter
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/C0OB90061C
A simple benzimidazole-based receptor for barbiturate and urea neutral guests that functions in polar solvent mixtures
Publisher: Royal Society of Chemistry (RSC)
Date: 2007
DOI: 10.1039/B705854C
Metal–organic anion receptors: trans-functionalised platinum complexes
Publisher: Royal Society of Chemistry (RSC)
Date: 2008
DOI: 10.1039/B816002C
Abstract: The anion complexation properties of a trans-functionalised platinum(II) complex have been studied revealing a high affinity for sulfate in solution and 3:2 receptor sulfate complex formation in the solid state with the anion bound in a pocket lined with 6 NH and 8 CH hydrogen-bond-donating groups.
Anion-induced conformational changes in 2,7-disubstituted indole-based receptors
Publisher: Royal Society of Chemistry (RSC)
Date: 2009
DOI: 10.1039/B908947K
Abstract: The conformational preorganization and anion-induced conformational changes of indole-based receptors functionalized with an amide group at the 2-position and a variety of amide, urea and thiourea moieties at the 7-position have been studied by the means of NMR spectroscopy. NOE experiments showed that anti-anti orientation across C2-C2alpha and C7-N7alpha bonds is preferred for receptors 1-4 in acetone solution in the absence of anions. Anion-receptor interactions have been evaluated through (1)H and (15)N chemical shift changes. In 2,7-bis-carboxamido functionalized indoles the interaction with chloride and bromide anions primarily occurs at the indole H1 proton. The introduction of urea and thiourea moieties increases the number of hydrogen bond donor sites which manifests itself in a distribution of halide-receptor interactions among the H1, H7alpha and H7gamma protons. Acetate anions also interact strongly with indole and urea NH donor groups, whereas nitrate anions interact solely with H7alpha and H7gamma urea/thiourea protons. NOE enhancements in the presence of anions revealed that anion-receptor complexes favour the syn-syn conformation of the C2 and C7 substituents.
meso-Octacyclopropylcalix[4]pyrrole ethanol solvate
Publisher: International Union of Crystallography (IUCr)
Date: 19-02-2001
Supramolecular chemistry anniversary
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7CS90037F
Abstract: Guest editors David B. Amabilino and Philip A. Gale introduce the Supramolecular Chemistry Anniversary issue of Chemical Society Reviews .
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