ORCID Profile
0000-0003-3161-3697
Current Organisations
Northwestern University
,
University of New South Wales
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Publisher: American Chemical Society (ACS)
Date: 30-03-2020
DOI: 10.1021/JACS.0C01989
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2CS00194B
Abstract: The year 2022 marks the 30th anniversary of the first reports of polyrotaxanes in the scientific literature.
Publisher: American Chemical Society (ACS)
Date: 18-05-2020
DOI: 10.1021/JACS.0C03408
Publisher: Proceedings of the National Academy of Sciences
Date: 21-12-2020
Publisher: American Chemical Society (ACS)
Date: 12-12-2022
DOI: 10.1021/JACS.2C10882
Publisher: American Chemical Society (ACS)
Date: 04-02-2020
DOI: 10.1021/JACS.9B13790
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D0CS00352B
Abstract: In this Review, we feature the recent developments in the chemistry of fluorescent cyclophanes, along with their design and synthesis. Their host–guest chemistry and applications related to their structure and properties are also highlighted.
Publisher: American Chemical Society (ACS)
Date: 17-09-2019
DOI: 10.1021/JACS.9B08758
Abstract: Tessellation of organic polygons though [π···π] and charge-transfer (CT) interactions offers a unique opportunity to construct supramolecular organic electronic materials with 2D topologies. Our approach to exploring the 3D topology of 2D tessellations of a naphthalene diimide-based molecular triangle (
Publisher: American Chemical Society (ACS)
Date: 23-11-2020
DOI: 10.1021/JACS.0C10339
Publisher: American Chemical Society (ACS)
Date: 11-08-2023
DOI: 10.1021/JACS.3C04213
Publisher: Wiley
Date: 09-01-2019
Publisher: American Chemical Society (ACS)
Date: 26-06-2023
DOI: 10.1021/JACS.3C04212
Publisher: Springer Science and Business Media LLC
Date: 30-10-2019
DOI: 10.1038/S41467-019-12857-4
Abstract: Currently, there is considerable interest in developing advanced rechargeable batteries that boast efficient distribution of electricity and economic feasibility for use in large-scale energy storage systems. Rechargeable aqueous zinc batteries are promising alternatives to lithium-ion batteries in terms of rate performance, cost, and safety. In this investigation, we employ Cu 3 (HHTP) 2 , a two-dimensional (2D) conductive metal-organic framework (MOF) with large one-dimensional channels, as a zinc battery cathode. Owing to its unique structure, hydrated Zn 2+ ions which are inserted directly into the host structure, Cu 3 (HHTP) 2 , allow high diffusion rate and low interfacial resistance which enable the Cu 3 (HHTP) 2 cathode to follow the intercalation pseudocapacitance mechanism. Cu 3 (HHTP) 2 exhibits a high reversible capacity of 228 mAh g −1 at 50 mA g −1 . At a high current density of 4000 mA g −1 (~18 C), 75.0% of the initial capacity is maintained after 500 cycles. These results provide key insights into high-performance, 2D conductive MOF designs for battery electrodes.
Publisher: Wiley
Date: 28-06-2018
Abstract: Artificial molecular machines can be operated using either physical or chemical inputs. Light-powered motors display clean and autonomous operations, whereas chemically driven machines generate waste products and are intermittent in their motions. Herein, we show that controlled changes in applied electrochemical potentials can drive the operation of artificial molecular pumps in a semi-autonomous manner-that is, without the need for consecutive additions of chemical fuel(s). The electroanalytical approach described in this Communication promotes the assembly of cyclobis(paraquat-p-phenylene) rings along a positively charged oligomeric chain, providing easy access to the formation of multiple mechanical bonds by means of a controlled supply of electricity.
Publisher: Wiley
Date: 08-09-2016
Abstract: Since the advent of mechanically interlocked molecules (MIMs), many approaches to templating their formation using various different noncovalent bonding interactions have been introduced and explored. In particular, employing radical-pairing interactions between BIPY(.+) units, the radical cationic state of 4,4'-bipyridinium (BIPY(2+) ) units, in syntheses is not only a convenient but also an attractive source of templation because of the unique properties residing in the resulting catenanes and rotaxanes. Herein, we report a copper-mediated procedure that enables the generation, in the MIM-precursors, of BIPY(.+) radical cations, while the metal itself, which is oxidized to Cu(I) , catalyzes the azide-alkyne cycloaddition reactions that result in the efficient syntheses of two catenanes and one rotaxane, assisted by radical-pairing interactions between the BIPY(.+) radical cations. This procedure not only provides a fillip for making and investigating the properties of Coulombically challenged catenanes and rotaxanes, but it also opens up the possibility of synthesizing artificial molecular machines which operate away from equilibrium.
Publisher: American Chemical Society (ACS)
Date: 03-05-2018
DOI: 10.1021/JACS.8B03407
Abstract: An octacationic diazaperopyrenium (DAPP
Publisher: American Chemical Society (ACS)
Date: 30-06-2019
DOI: 10.1021/JACS.9B03990
Abstract: Prompted by a knowledge of the photoprotective mechanism operating in photosystem supercomplexes and bacterial antenna complexes by pigment binding proteins, we have appealed to a boxlike synthetic receptor (
Publisher: American Chemical Society (ACS)
Date: 21-02-2020
DOI: 10.1021/JACS.0C01114
Publisher: American Chemical Society (ACS)
Date: 10-09-2021
DOI: 10.1021/JACS.1C06333
Abstract: The development of synthetic receptors that recognize carbohydrates in water with high selectivity and specificity is challenging on account of their structural complexity and strong hydrophilicity. Here, we report on the design and synthesis of two pyrene-based, temple-shaped receptors for the recognition of a range of common sugars in water. These receptors rely on the use of two parallel pyrene panels, which serve as roofs and floors, capable of forming multiple [C-H···π] interactions with the axially oriented C-H bonds on glycopyranosyl rings in the carbohydrate-based substrates. In addition, eight polarized pyridinium C-H bonds, projecting from the roofs and floors of the temple receptors toward the binding cavities, form [C-H···O] hydrogen bonds, with the equatorially oriented OH groups on the sugars located inside the hydrophobic cavities. Four
Publisher: Wiley
Date: 26-01-2023
DOI: 10.1002/POL.20220691
Abstract: Rotaxanes with well‐defined ring sequences are attractive synthetic goals in the construction of functional materials associated with molecular shuttles and switches, molecular electronics, and information storage. Sequence‐controlled synthesis of oligo‐ and polyrotaxanes is important in the context of the development of both sequence‐defined polymers and dynamic functional materials. To date, ex les of sequence‐controlled rotaxanes are limited to oligorotaxanes on account of the synthetic challenges they pose. This Review sheds light on the pivotal role that sequence isomerism plays in rotaxanes. Synthetic approaches, including orthogonal templation, active‐metal templation, self‐sorting and snapping, cooperative‐capturing, ring‐through‐ring‐shuttling, and molecular pumping, for the construction of sequence‐controlled rotaxanes are all discussed in this Review. By comparing the advantages and disadvantages of these different approaches, several possible synthetic strategies are proposed in an attempt to foretell the future of sequence‐controlled synthesis of polyrotaxanes.
Publisher: American Chemical Society (ACS)
Date: 27-06-2018
DOI: 10.1021/JACS.8B05322
Abstract: Herein, we report an unprecedented mixed-valence crystal superstructure that consists of a 2:1 host-guest complex [MV⊂(CBPQT)
Publisher: American Chemical Society (ACS)
Date: 28-09-2018
DOI: 10.1021/JACS.8B08555
Abstract: Along with the advent of supramolecular chemistry, research on fullerene receptors based on noncovalent bonding interactions has attracted a lot of attention. Here, we present the design and synthesis of a cationic molecular cage: a cyclophane composed of two tetraphenylporphyrins, bridged face-to-face by four viologen units in a rhomboid prismatic manner. The large cavity inside the cage, as well as the favorable donor-acceptor interactions between the porphyrin panels and the fullerene guests, enables the cage to be an excellent fullerene receptor. The 1:1 host-guest complexes formed between the cage and both C
Publisher: Springer Science and Business Media LLC
Date: 03-12-2018
Publisher: American Chemical Society (ACS)
Date: 17-10-2019
DOI: 10.1021/JACS.9B08927
Abstract: Artificial molecular machines (AMMs) built from mechanically interlocked molecules (MIMs) can use energy ratchets to control the unidirectional motion of their component parts. These energy ratchets are operated by the alteration of kinetic barriers and thermodynamic wells, which are, in turn, determined by the switching on and off of noncovalent interactions. Previously, we have developed artificial molecular pumps (AMPs) capable of pumping rings consecutively onto a collecting chain as part of a molecular dumbbell, leading to the formation of rotaxanes. Here, we report a molecular dual pump (MDP) consisting of two in idual AMPs linked in a head-to-tail fashion, wherein a single ring is pumped, in a linear manner, on and off a dumbbell involving a [2]rotaxane intermediate by exploiting the redox properties of the two pumps. This MDP, defined by the finely tuned noncovalent interactions and fueled by either chemicals or electricity, utilizes an energy ratchet mechanism to capture a ring and subsequently release it back into solution. The unidirectional motion and the resulting
Publisher: Wiley
Date: 24-11-2022
Abstract: The tetracationic cyclophane, cyclobis(paraquat‐ p ‐phenylene), also known as the little blue box, constitutes a modular receptor that has facilitated the discovery of many host–guest complexes and mechanically interlocked molecules during the past 35 years. Its versatility in binding small π‐donors in its tetracationic state, as well as forming trisradical tricationic complexes with viologen radical cations in its doubly reduced bisradical dicationic state, renders it valuable for the construction of various stimuli‐responsive materials. Since the first reports in 1988, the little blue box has been featured in over 500 publications in the literature. All this research activity would not have been possible without the seminal contributions carried out by Siegfried Hünig, who not only pioneered the syntheses of viologen‐containing cyclophanes, but also revealed their rich redox chemistry in addition to their ability to undergo intramolecular π‐dimerization. This Review describes how his pioneering research led to the design and synthesis of the little blue box, and how this redox‐active host evolved into the key component of molecular shuttles, switches, and machines.
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0QM90014A
Abstract: Jishan Wu and Fraser Stoddart introduce the Materials Chemistry Frontiers themed collection on mechanical bonds and dynamic covalent bonds.
Publisher: American Chemical Society (ACS)
Date: 14-08-2023
DOI: 10.1021/JACS.3C04340
Publisher: American Chemical Society (ACS)
Date: 13-12-2022
DOI: 10.1021/JACS.2C10591
Publisher: American Chemical Society (ACS)
Date: 02-03-2022
Publisher: American Association for the Advancement of Science (AAAS)
Date: 17-04-2020
Abstract: The pressure for onboard storage of methane and hydrogen on vehicles is usually limited to 100 bar for the use of lightweight containers, but the amount stored can be increased with the use of absorbent materials. Efficient storage and delivery require a balance of volumetric and gravimetric storage. Chen et al. designed a metal-organic framework with trialuminum nodes and a large hexadentate aromatic linker that optimizes both parameters. This material surpassed the U.S. Department of Energy targets for methane and had a deliverable capacity of 14% by weight for hydrogen. Science , this issue p. 297
Publisher: American Chemical Society (ACS)
Date: 09-09-2022
DOI: 10.1021/JACS.2C04906
Abstract: Polar and polarizable π-conjugated organic molecules containing push-pull chromophores have been investigated extensively in the past. Identifying unique backbones and building blocks for fluorescent dyes is a timely exercise. Here, we report the synthesis and characterization of a series of fluorescent dyes containing quadrupolar A-D-A constitutions (where A = acceptor and D = donor), which exhibit fluorescence emission at a variety of different wavelengths. We have investigated the effects of different electron-withdrawing groups, located at both termini of a
Publisher: Wiley
Date: 29-06-2020
Publisher: Springer Science and Business Media LLC
Date: 09-03-2022
DOI: 10.1038/S41586-021-04377-3
Abstract: Molecular recognition
Publisher: American Chemical Society (ACS)
Date: 19-09-2019
DOI: 10.1021/JACS.9B08926
Abstract: Organic radicals are of importance in developing smart materials that have paramagnetic and/or near-infrared optical properties. Their practical applications, however, are limited by the labile nature of the radicals. Here, we demonstrate that by using a tetracationic cyclophane, namely, cyclobis(4,4'-(1,4-phenylene)bispyridine-
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/C9SC04860J
Abstract: Although host–guest pairing interactions between bisradical dicationic cyclobis(paraquat- p -phenylene) ( BB2(˙+) ) and the bipyridinium radical cation ( BIPY˙+ ) have been studied extensively, host molecules other than BB2(˙+) are few and far between.
Publisher: Wiley
Date: 11-07-2021
Abstract: Supramolecular assembly is a promising bottom‐up approach for producing materials that behave as charge transporting components in electronic devices. Although extensive advances have been made during the past two decades, formidable challenges exist in controlling the local randomness present in supramolecular assemblies. Here, a temperature‐triggered supramolecular assembly strategy using heat to heal defects and disorders is reported. The central concept of the molecular design—named the "Tetris strategy" in this research—is to: i) increase the rotational freedom of the molecules through thermal perturbation, ii) induce conformation‐fitting of adjacent molecules through two different kinds of intermolecular [π···π] interactions, and finally iii) lock the nearby molecules in inactive co‐conformations. Experimentally, upon heating to 57 °C, amorphous solid‐state films undergo spontaneous assembly, leading to the growth of uniform and highly ordered microwire arrays. Temperature‐triggered supramolecular assembly provides an approach closer to the precision control of assembled structures and presents with a broad canvas to work on in approaching a new generation of supramolecular electronics. Tetris is a registered trademark of Tetris Holding, LLC, used with permission.
Publisher: American Chemical Society (ACS)
Date: 16-01-2020
DOI: 10.1021/JACS.9B12982
Abstract: The rational design of wholly synthetic receptors that bind active substrates with ultrahigh affinities is a challenging goal, especially in water. Here, we report the synthesis of a tricyclic octacationic cyclophane, which exhibits complementary stereoelectronic binding toward a widely used fluorescent dye, perylene diimide, with picomolar affinity in water. The ultrahigh binding affinity is sustained by a large and rigid hydrophobic binding surface, which provides a highly favorable enthalpy and a slightly positive entropy of complexation. The receptor-substrate complex shows significant improvement in optical properties, including red-shifted absorption and emission, turn-on fluorescence, and efficient energy transfer. An unusual single-excitation, dual-emission, imaging study of living cells was performed by taking advantage of a large pseudo-Stokes shift, produced by the efficient energy transfer.
Publisher: American Chemical Society (ACS)
Date: 18-05-2021
DOI: 10.1021/JACS.1C02789
Abstract: Macrocycles that assemble into nanotubes exhibit emergent properties stemming from their low dimensionality, structural regularity, and distinct interior environments. We report a versatile strategy to synthesize erse nanotube structures in a single, efficient reaction by using a conserved building block bearing a pyridine ring. Imine condensation of a 2,4,6-triphenylpyridine-based diamine with various aromatic dialdehydes yields chemically distinct pentagonal [5 + 5], hexagonal [3 + 3], and diamond-shaped [2 + 2] macrocycles depending on the substitution pattern of the aromatic dialdehyde monomer. Atomic force microscopy and
Publisher: American Chemical Society (ACS)
Date: 03-04-2020
DOI: 10.1021/JACS.0C02311
Publisher: American Chemical Society (ACS)
Date: 13-10-2020
Publisher: American Chemical Society (ACS)
Date: 29-09-2017
DOI: 10.1021/JACS.7B08275
Abstract: Facile exciton transport within ordered assemblies of π-stacked chromophores is essential for developing molecular photonic and electronic materials. Excimer states having variable charge transfer (CT) character are frequently implicated as promoting or inhibiting exciton mobility in such systems. However, determining the degree of CT character in excimers as a function of their structure has proven challenging. Herein, we report on a series of cyclophanes in which the interplanar distance between two phenyl-extended viologen (ExV
Publisher: American Chemical Society (ACS)
Date: 21-09-2023
DOI: 10.1021/JACS.3C06371
Publisher: American Chemical Society (ACS)
Date: 13-09-2017
Abstract: At the interface between foldamers and mechanically interlocked molecules, oligorotaxanes exhibit a spring-like folded secondary structure with remarkable mechanical and physicochemical properties. Among these properties, the ability of oligorotaxanes to act as molecular switches through controlled modulations of their spatial extension over (un)folding dynamics is of particular interest. The present study aims to assess and further characterize this remarkable feature in the gas phase using mass spectrometry tools. In this context, we focused on the [4]5NPR
Publisher: American Chemical Society (ACS)
Date: 30-09-2022
Publisher: American Chemical Society (ACS)
Date: 08-02-2019
DOI: 10.1021/JACS.8B13710
Abstract: Metal-organic frameworks (MOFs) based on edge-transitive 6-c acs nets are well-developed and can be synthesized from trinuclear metal clusters and ditopic ligands, i.e., MOF-235 and MIL-88. The rational design of noncatenated acs-MOFs by symmetry-matching between trigonal prismatic organic ligands and trinuclear clusters, however, remains a great challenge. Herein, we report a series of acs-MOFs (NU-1500) based on trivalent trinuclear metal (Fe
Publisher: American Chemical Society (ACS)
Date: 12-2022
DOI: 10.1021/JACS.2C08623
Abstract: Tröger's base (TB) and its derivatives have been studied extensively due to their unique concave shape stemming from the endomethylene strap. However, the strap-clipped TB chemistry has been largely overlooked in metal-organic framework (MOF) solids, leading to a gap in our knowledge within this field. In this work, we report the in situ strap elimination of a carboxylate-carrying TB in the presence of formic acid, both in solution and in Zr(IV)-based MOFs. In the solution system, the methanodiazocine nucleus can be exclusively transformed into an
Publisher: American Chemical Society (ACS)
Date: 12-04-2023
DOI: 10.1021/JACS.3C01244
Publisher: American Chemical Society (ACS)
Date: 31-03-2022
Publisher: American Chemical Society (ACS)
Date: 30-12-2020
DOI: 10.1021/JACS.0C11769
Publisher: American Chemical Society (ACS)
Date: 12-03-2019
DOI: 10.1021/JACS.8B13675
Abstract: Constructing multicolor photoluminescence materials that allow for the integration of suitable external stimuli in order to control luminescence color conversions is a challenging objective. Multicolor luminescent output that is regulated in an in situ photo-controlled manner is not a common phenomenon. Herein, a photoluminescent supramolecular assembly, prepared in two stages, is described that displays in situ photo-tuning broad-spectrum output. Benefiting from the reversible photo-switched constitutional interconversion of diarylethenes, the fluorescence of a guest molecule, styrylpyridinium-modified diarylethene, can be switched on/off by alternating ultraviolet and visible light irradiation. Upon complexation of this guest with a host, cucurbit[8]uril, the fluorescence intensity of the resulting binary supramolecular nanofiber shows a drastic enhancement when compared with that of the free guest, which can also be quenched and recovered reversibly by light irradiation. Significantly, such cationic supramolecular nanofibers also interact with anionic carbon dots to form broad-spectrum output ternary supramolecular assemblies, the fluorescence of which can be changed efficiently from yellow to blue in an in situ photo-controlled manner. Pure white light emission can be realized expediently in the luminescence color-conversion process. The use of light as an external stimulus to regulate fluorescent color conversion provides us with an opportunity to design and construct more advanced anti-counterfeiting materials as well as visual display instruments.
Publisher: Oxford University Press (OUP)
Date: 16-02-2023
DOI: 10.1093/NSR/NWAD041
Publisher: American Chemical Society (ACS)
Date: 16-09-2019
Abstract: Allomelanin is a type of nitrogen-free melanin most commonly found in fungi. Its existence enhances resistance of the organisms to environmental damage and helps fungi survive harsh radiation conditions such as those found on spacecraft and inside contaminated nuclear power plants. We report the preparation and characterization of artificial allomelanin nanoparticles (AMNPs)
Publisher: American Chemical Society (ACS)
Date: 20-05-2022
DOI: 10.1021/JACS.2C01554
Abstract: Three achiral polycyclic aromatic fluorophores─namely, 1-pyrenecarboxylic acid, 9-anthracenecarboxylic acid, and perylene-3,9-dicarboxylic acid─were chosen based on their desired properties before being incorporated into the construction of a K
Publisher: American Association for the Advancement of Science (AAAS)
Date: 03-12-2021
Abstract: Numerous chemical processes, ranging from water purification to catalysis, involve sorption of small molecules onto surfaces. Typically, spontaneous attractive interactions favor the binding event. Feng et al . report a mechanisorption process that requires redox manipulations to pump macrocycles from bulk solution onto axles immobilized on a metal-organic framework. The resulting rotaxanes store energy through nonequilibrium charge concentration in their mechanical bonds. Ultimately, the technique could also prove useful for actively partitioning compounds with particular functionality between surface and bulk environments. —JSY
Publisher: American Chemical Society (ACS)
Date: 02-01-2020
DOI: 10.1021/JACS.9B12436
Abstract: Aqueous rechargeable zinc batteries (ZBs) have received considerable attention recently for large-scale energy storage systems in terms of rate performance, cost, and safety. Nevertheless, these ZBs still remain a subject for investigation, as researchers search for cathode materials enabling high performance. Among the various candidate cathode materials for ZBs, quinone compounds stand out as candidates because of their high specific capacity, sustainability, and low cost. Quinone-based cathodes, however, suffer from the critical limitation of undergoing dissolution during battery cycling, leading to a deterioration in battery life. To address this problem, we have introduced a redox-active triangular phenanthrenequinone-based macrocycle (
Publisher: Springer Science and Business Media LLC
Date: 06-09-2022
Publisher: Wiley
Date: 07-09-2021
Abstract: Complexation between a viologen radical cation ( V .+ ) and cyclobis(paraquat‐ p ‐phenylene) diradical dication ( CBPQT 2(.+) ) has been investigated and utilized extensively in the construction of mechanically interlocked molecules (MIMs) and artificial molecular machines (AMMs). The selective recognition of a pair of V .+ using radical‐pairing interactions, however, remains a formidable challenge. Herein, we report the efficient encapsulation of two methyl viologen radical cations ( MV .+ ) in a size‐matched bisradical dicationic host — namely, cyclobis(paraquat‐2,6‐naphthalene) 2(.+) , i.e., CBPQN 2(.+) . Central to this dual recognition process was the choice of 2,6‐bismethylenenaphthalene linkers for incorporation into the bisradical dicationic host. They provide the space between the two bipyridinium radical cations in CBPQN 2(.+) suitable for binding two MV .+ with relatively short (3.05–3.25 Å) radical‐pairing distances. The size‐matched bisradical dicationic host was found to exhibit highly selective and cooperative association with the two MV .+ in MeCN at room temperature. The formation of the tetrakisradical tetracationic inclusion complex — namely, [ (MV) 2 ⊂ CBPQN ] 4( .+) – in MeCN was confirmed by VT 1 H NMR, as well as by EPR spectroscopy. The solid‐state superstructure of [ (MV) 2 ⊂ CBPQN ] 4( .+) reveals an uneven distribution of the binding distances (3.05, 3.24, 3.05 Å) between the three different V .+ , suggesting that localization of the radical‐pairing interactions has a strong influence on the packing of the two MV .+ inside the bisradical dicationic host. Our findings constitute a rare ex le of binding two radical guests with high affinity and cooperativity using host‐guest radical‐pairing interactions. Moreover, they open up possibilities of harnessing the tetrakisradical tetracationic inclusion complex as a new, orthogonal and redox‐switchable recognition motif for the construction of MIMs and AMMs.
Publisher: American Chemical Society (ACS)
Date: 29-03-2021
DOI: 10.1021/JACS.1C00298
Publisher: Springer Science and Business Media LLC
Date: 15-09-2020
DOI: 10.1038/S41467-020-18431-7
Abstract: Two-photon excited near-infrared fluorescence materials have garnered considerable attention because of their superior optical penetration, higher spatial resolution, and lower optical scattering compared with other optical materials. Herein, a convenient and efficient supramolecular approach is used to synthesize a two-photon excited near-infrared emissive co-crystalline material. A naphthalenediimide-based triangular macrocycle and coronene form selectively two co-crystals. The triangle-shaped co-crystal emits deep-red fluorescence, while the quadrangle-shaped co-crystal displays deep-red and near-infrared emission centered on 668 nm, which represents a 162 nm red-shift compared with its precursors. Benefiting from intermolecular charge transfer interactions, the two co-crystals possess higher calculated two-photon absorption cross-sections than those of their in idual constituents. Their two-photon absorption bands reach into the NIR-II region of the electromagnetic spectrum. The quadrangle-shaped co-crystal constitutes a unique material that exhibits two-photon absorption and near-infrared emission simultaneously. This co-crystallization strategy holds considerable promise for the future design and synthesis of more advanced optical materials.
Publisher: American Chemical Society (ACS)
Date: 02-03-2018
Publisher: American Chemical Society (ACS)
Date: 22-07-2019
DOI: 10.1021/JACS.9B06445
Abstract: Herein we report a hydrogen-bonded three-dimensional porous supramolecular polyknot assembled from a rigid trigonal prismatic triptycene building block with six extended peripheral aryl-carboxyl groups. Within this superstructure, three arrays of undulated 2D rhombic subnets, which display an inclined polycatenation, are interconnected to give an unprecedented uninodal six-connected net with a point symbol of (3.4
Publisher: American Chemical Society (ACS)
Date: 25-09-2018
DOI: 10.1021/JACS.8B08519
Abstract: The redox properties of cyclobis(paraquat- p-phenylene)cyclophane (CBPQT
Publisher: Springer Science and Business Media LLC
Date: 11-01-2023
DOI: 10.1038/S41586-022-05421-6
Abstract: Macroscopic electric motors continue to have a large impact on almost every aspect of modern society. Consequently, the effort towards developing molecular motors 1–3 that can be driven by electricity could not be more timely. Here we describe an electric molecular motor based on a [3]catenane 4,5 , in which two cyclobis(paraquat- p -phenylene) 6 (CBPQT 4+ ) rings are powered by electricity in solution to circumrotate unidirectionally around a 50-membered loop. The constitution of the loop ensures that both rings undergo highly (85%) unidirectional movement under the guidance of a flashing energy ratchet 7,8 , whereas the interactions between the two rings give rise to a two-dimensional potential energy surface (PES) similar to that shown by F O F 1 ATP synthase 9 . The unidirectionality is powered by an oscillating 10 voltage 11,12 or external modulation of the redox potential 13 . Initially, we focused our attention on the homologous [2]catenane, only to find that the kinetic asymmetry was insufficient to support unidirectional movement of the sole ring. Accordingly, we incorporated a second CBPQT 4+ ring to provide further symmetry breaking by interactions between the two mobile rings. This demonstration of electrically driven continual circumrotatory motion of two rings around a loop in a [3]catenane is free from the production of waste products and represents an important step towards surface-bound 14 electric molecular motors.
Publisher: American Chemical Society (ACS)
Date: 08-04-2021
DOI: 10.1021/JACS.0C13388
Publisher: Springer Science and Business Media LLC
Date: 04-2021
Publisher: Springer Science and Business Media LLC
Date: 18-06-2021
Publisher: Springer Science and Business Media LLC
Date: 31-08-2021
DOI: 10.1038/S41467-021-25255-6
Abstract: Nanographenes have kindled considerable interest in the fields of materials science and supramolecular chemistry as a result of their unique self-assembling and optoelectronic properties. Encapsulating the contorted nanographenes inside artificial receptors, however, remains challenging. Herein, we report the design and synthesis of a trigonal prismatic hexacationic cage, which has a large cavity and adopts a relatively flexible conformation. It serves as a receptor, not only for planar coronene, but also for contorted nanographene derivatives with diameters of approximately 15 Å and thicknesses of 7 Å. A comprehensive investigation of the host-guest interactions in the solid, solution and gaseous states by experimentation and theoretical calculations reveals collectively an induced-fit binding mechanism with high binding affinities between the cage and the nanographenes. Notably, the photostability of the nanographenes is improved significantly by the ultrafast deactivation of their excited states within the cage. Encapsulating the contorted nanographenes inside the cage provides a noncovalent strategy for regulating their photoreactivity.
Publisher: American Chemical Society (ACS)
Date: 02-07-2020
Publisher: American Chemical Society (ACS)
Date: 26-09-2020
DOI: 10.1021/JACS.0C07784
Publisher: American Chemical Society (ACS)
Date: 21-12-2020
DOI: 10.1021/JACS.0C07148
Publisher: American Chemical Society (ACS)
Date: 02-2021
Publisher: Springer Science and Business Media LLC
Date: 02-10-2023
Publisher: American Chemical Society (ACS)
Date: 25-07-2019
DOI: 10.1021/JACS.9B06179
Abstract: Zirconium-based metal-organic frameworks (Zr-MOFs) based on
Publisher: American Chemical Society (ACS)
Date: 29-06-2017
DOI: 10.1021/JACS.7B02279
Abstract: Ferroelectricity in organic materials remains a subject of great interest, given its potential impact as lightweight information storage media. Here we report supramolecular charge-transfer cocrystals formed by electron acceptor and donor molecules that exhibit ferroelectric behavior along two distinct crystallographic axes. The solid-state superstructure of the cocrystals reveals that a 2:1 ratio of acceptor to donor molecules assemble into nearly orthogonal mixed stacks in which the molecules are positioned for charge-transfer in face-to-face and edge-to-face orientations, held together by an extended hydrogen-bonding network. Polarization hysteresis was observed along the face-to-face and edge-to-face axes at room temperature. The noncentrosymmetric nature of the cocrystals, required to observe ferroelectric behavior, is demonstrated using second harmonic generation measurements. This finding suggests the possibility of designing supramolecular arrays in which organic molecules support multidimensional information storage.
Publisher: American Chemical Society (ACS)
Date: 17-08-2023
DOI: 10.1021/JACS.3C03282
Publisher: American Chemical Society (ACS)
Date: 08-03-2017
DOI: 10.1021/JACS.6B09892
Abstract: Persistent π-radicals such as MV
Publisher: Elsevier BV
Date: 04-2022
Publisher: American Chemical Society (ACS)
Date: 05-06-2018
Abstract: Exactly 50 years ago, the ground-breaking discovery of dibenzo[18]crown-6 (DB18C6) by Charles Pedersen led to the use of DB18C6 as a receptor in supramolecular chemistry and a host in host-guest chemistry. We have demonstrated proton conductivity in Tröger's base-linked polymers through hydrogen-bonded networks formed from adsorbed water molecules on the oxygen atoms of DB18C6 under humid conditions. Tröger's base-linked polymers-poly(TBL-DB18C6)- t and poly(TBL-DB18C6)- c-synthesized by the in situ alkylation and cyclization of either trans- or cis-di(aminobenzo) [18]crown-6 at room temperature have been isolated as high-molecular-weight polymers. The macromolecular structures of the isomeric poly(TBL-DB18C6)s have been established by spectroscopic techniques and size-exclusion chromatography. The excellent solubility of these polymers in chloroform allows the formation of freestanding membranes, which are thermally stable and also show stability under aqueous conditions. The hydrophilic nature of the DB18C6 building blocks in the polymer facilitates retention of water as confirmed by water vapor adsorption isotherms, which show a 23 wt % water uptake. The adsorbed water is retained even after reducing the relative humidity to 25%. The proton conductivity of poly(TBL-DB18C6)- t, which is found to be 1.4 × 10
Publisher: Wiley
Date: 22-08-2022
Abstract: Here, we report an approach to the synthesis of highly charged enantiopure cyclophanes by the insertion of axially chiral enantiomeric binaphthyl fluorophores into the constitutions of pyridinium‐based macrocycles. Remarkably, these fluorescent tetracationic cyclophanes exhibit a significant AIE compared to their neutral optically active binaphthyl precursors. A combination of theoretical calculations and time‐resolved spectroscopy reveal that the AIE originates from limited torsional vibrations associated with the axes of chirality present in the chiral enantiomeric binaphthyl units and the fine‐tuning of their electronic landscape when incorporated within the cyclophane structure. Furthermore, these highly charged enantiopure cyclophanes display CPL responses both in solution and in the aggregated state. This unique duality of AIE and CPL in these tetracationic cyclophanes is destined to be of major importance in future development of photonic devices and bio‐applications.
Publisher: American Chemical Society (ACS)
Date: 09-08-2018
DOI: 10.1021/JACS.8B06609
Abstract: A class of metal-organic frameworks (MOFs)-namely CD-MOFs-obtained from natural products has been grown in an epitaxial fashion as films on the surfaces of glass substrates, which are modified with self-assembled monolayers (SAMs) of γ-cyclodextrin (γ-CD) molecules. The SAMs are created by host-guest complexation of γ-CD molecules with surface-functionalized pyrene units. The CD-MOF films have continuous polycrystalline morphology with a structurally out-of-plane ( c-axial) orientation, covering an area of several square millimeters, with a thickness of ∼2 μm. Furthermore, this versatile host-guest strategy has been applied successfully in the growth of CD-MOFs as the shell on the curved surface of microparticles as well as in the integration of CD-MOF films into electrochemical devices for sensing carbon dioxide. In striking contrast to the control devices prepared from CD-MOF crystalline powders, these CD-MOF film-based devices display an enhancement in proton conductance of up to 300-fold. In addition, the CD-MOF film-based device exhibits more rapid and highly reversible CO
Publisher: American Chemical Society (ACS)
Date: 07-07-2022
DOI: 10.1021/JACS.2C00515
Abstract: Mechanochemical syntheses of rotaxanes have attracted considerable attention of late because of the superior reaction rates and higher yields associated with their production compared with analogous reactions carried out in solution. Previous investigators, however, have focused on the demonstration of the mechanochemical syntheses of rotaxanes per se, rather than on studying the solid-phase host-guest molecular interplay related to their rapid formation and high yields. In this investigation, we attribute the lower yields of rotaxanes prepared in solution to the limited concentration and a desolvation energy penalty that must be compensated for by host-guest interactions during complexation that precedes the templation leading to rotaxane formation. It follows that, if the desolvation energy can be removed and higher concentrations can be attained, even weak host-guest interactions can drive the complexation of host and guest molecules efficiently. In order to test this hypothesis, we chose two host-guest pairs of permethylated pillar[5]arene/1,6-diaminohexane and permethylated pillar[5]arene/2,2'-(ethylenedioxy)bis(ethylamine) for the simple reason that they exhibit extremely low binding constants (2.7 ± 0.4 M
Publisher: Springer Science and Business Media LLC
Date: 09-03-2023
DOI: 10.1038/S41467-023-36591-0
Abstract: Developing an eco-friendly, efficient, and highly selective gold-recovery technology is urgently needed in order to maintain sustainable environments and improve the utilization of resources. Here we report an additive-induced gold recovery paradigm based on precisely controlling the reciprocal transformation and instantaneous assembly of the second-sphere coordinated adducts formed between β-cyclodextrin and tetrabromoaurate anions. The additives initiate a rapid assembly process by co-occupying the binding cavity of β-cyclodextrin along with the tetrabromoaurate anions, leading to the formation of supramolecular polymers that precipitate from aqueous solutions as cocrystals. The efficiency of gold recovery reaches 99.8% when dibutyl carbitol is deployed as the additive. This cocrystallization is highly selective for square-planar tetrabromoaurate anions. In a laboratory-scale gold-recovery protocol, over 94% of gold in electronic waste was recovered at gold concentrations as low as 9.3 ppm. This simple protocol constitutes a promising paradigm for the sustainable recovery of gold, featuring reduced energy consumption, low cost inputs, and the avoidance of environmental pollution.
Publisher: American Chemical Society (ACS)
Date: 05-07-2022
DOI: 10.1021/JACS.2C03114
Abstract: Industrial-scale thermal separation processes have contributed greatly to the rise in carbon dioxide emissions. Porous materials, such as metal-organic frameworks (MOFs), can potentially reduce these emissions by achieving nonthermal chemical separations through the physical adsorption of targeted species with high selectivity. Here, we report the synthesis of the channel-based MOFs
Publisher: Springer Science and Business Media LLC
Date: 09-06-2021
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C8SC05514A
Abstract: Photo-driven electron transfer is faster from an electron donor guest to the harder to reduce acceptor in an asymmetric cyclophane host.
Publisher: American Chemical Society (ACS)
Date: 28-05-2020
DOI: 10.1021/JACS.0C04029
Publisher: American Chemical Society (ACS)
Date: 06-04-2023
Publisher: American Chemical Society (ACS)
Date: 27-05-2021
DOI: 10.1021/JACS.1C03141
Publisher: American Chemical Society (ACS)
Date: 04-2020
DOI: 10.1021/JACS.0C02128
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9SC00591A
Abstract: Lateral interactions enhance the guest inclusion and peripheral complexation within a highly charged covalent cage.
Publisher: American Chemical Society (ACS)
Date: 10-03-2017
DOI: 10.1021/JACS.6B13223
Abstract: Molecules capable of performing highly efficient energy transfer and ultrafast photoinduced electron transfer in well-defined multichromophoric structures are indispensable to the development of artificial photofunctional systems. Herein, we report on the synthesis, characterization, and photophysical properties of a rationally designed multichromophoric tetracationic cyclophane, DAPPBox
Publisher: American Chemical Society (ACS)
Date: 17-05-2018
DOI: 10.1021/JACS.8B03066
Abstract: The ideal fluorescent probe for live-cell imaging is bright and non-cytotoxic and can be delivered easily into the living cells in an efficient manner. The design of synthetic fluorophores having all three of these properties, however, has proved to be challenging. Here, we introduce a simple, yet effective, strategy based on well-established chemistry for designing a new class of fluorescent probes for live-cell imaging. A box-like hybrid cyclophane, namely ExTzBox·4X (6·4X, X = PF
Publisher: Wiley
Date: 30-06-2021
Abstract: The recognition and separation of anions attracts attention from chemists, materials scientists, and engineers. Employing exo‐binding of artificial macrocycles to selectively recognize anions remains a challenge in supramolecular chemistry. We report the instantaneous co‐crystallization and concomitant co‐precipitation between [PtCl 6 ] 2− dianions and cucurbit[6]uril, which relies on the selective recognition of these dianions through noncovalent bonding interactions on the outer surface of cucurbit[6]uril. The selective [PtCl 6 ] 2− dianion recognition is driven by weak [Pt−Cl⋅⋅⋅H−C] hydrogen bonding and [Pt−Cl⋅⋅⋅C=O] ion–dipole interactions. The synthetic protocol is highly selective. Recognition is not observed in combinations between cucurbit[6]uril and six other Pt‐ and Pd‐ or Rh‐based chloride anions. We also demonstrated that cucurbit[6]uril is able to separate selectively [PtCl 6 ] 2− dianions from a mixture of [PtCl 6 ] 2− , [PdCl 4 ] 2− , and [RhCl 6 ] 3− anions. This protocol could be exploited to recover platinum from spent vehicular three‐way catalytic converters and other platinum‐bearing metal waste.
Publisher: American Chemical Society (ACS)
Date: 03-10-2019
DOI: 10.1021/JACS.9B07877
Abstract: A series of donor-acceptor (D-A) naphthalene-viologen-based cyclophanes of different shapes, sizes, and symmetries have been synthesized and characterized. Solution optical studies on these cyclophanes reveal the existence of photoinduced intramolecular charge transfer (CT) at 465 nm from naphthalene (D) to viologen (A) units, resulting in a conformational change in the viologen units and the emergence of an emission at 540 nm. The D-A cyclophanes with box-like and hexagon-like shapes offer an opportunity to control the arrangement within 2D layers where D-A interactions direct the superstructures. While a box-like 2,6-disubstituted naphthalene-based tetracationic cyclophane does not form square tiling patterns, a truncated hexagon-like congener self-assembles to form a hexagonal superstructure which, in turn, adopts a hexagonal tiling pattern. Tessellation of the more rigid and highly symmetrical 2,7-disubstituted naphthalene-based cyclophanes leads to the formation of 2D square and honeycomb tiling patterns with the box-like and hexagon-like cyclophanes, respectively. Co-crystallization of the box-like cyclophanes with tetrathiafulvalene (
Publisher: American Chemical Society (ACS)
Date: 21-12-2017
DOI: 10.1021/JACS.7B12124
Abstract: The synthesis of stable organic polyradicals is important for the development of magnetic materials. Herein we report the synthesis, isolation, and characterization of a series of X-shaped pyromellitimide (PI) oligomers (X
Publisher: Wiley
Date: 14-10-2021
Publisher: Wiley
Date: 09-01-2019
Abstract: We describe an ex le of "interpenetration isomerism" in three-dimensional hydrogen-bonded organic frameworks. By exploiting the crystallization conditions for a peripherally extended triptycene H
Publisher: American Chemical Society (ACS)
Date: 14-07-2020
Publisher: American Chemical Society (ACS)
Date: 03-11-2020
Publisher: American Chemical Society (ACS)
Date: 08-09-2022
DOI: 10.1021/JACS.2C05405
Abstract: Traditionally, the synthesis of polyrotaxanes has been limited by synthetic methods that rely on an innate affinity between the rings and the polymer chains. The use of rotaxane-forming molecular pumps allows this limitation to be circumvented in the production of non-equilibrium polyrotaxanes in which rings are trapped on polymer chains for which they have little or no affinity. Pumping cassettes, each composed of a bipyridinium unit linked (i) by a bismethylene bridge to a terminal 2,6-dimethylpyridinium cationic unit and (ii) by a methylene group to an isopropylphenylene steric barrier, were attached using copper-catalyzed azide-alkyne cycloadditions to the ends of a polypropylene glycol (PPG) chain of number-average molecular weight
Publisher: Wiley
Date: 21-07-2016
Abstract: Covalent and supramolecular polymerizations, both of which offer their own unique advantages, have emerged as popular strategies for making artificial materials. Herein, we describe a concurrent covalent and supramolecular polymerization strategy-namely, one which utilizes 1) a bis-azide-functionalized diazaperopyrenium dication that undergoes polymeriation covalently with a bis-alkyne-functionalized biphenyl derivative in one dimension as a result of a rapid and efficient β-cyclodextrin(CD)-accelerated, cucurbit[6]uril(CB)-templated azide-alkyne cycloaddition, while 2) the aromatic core of the dication is able to dimerize in a criss-cross fashion by dint of π-π interactions, enabling simultaneous supramolecular assembly, resulting in an extended polymer network in an orthogonal dimension.
Publisher: American Chemical Society (ACS)
Date: 03-06-2021
DOI: 10.1021/JACS.1C03277
Publisher: American Chemical Society (ACS)
Date: 17-02-2017
DOI: 10.1021/JACS.7B00515
Abstract: Crystalline supramolecular frameworks consisting of charged molecules, held together by hydrogen bonds and Coulomb interactions, have attracted great interest because of their unusual structural, chemical, electronic, and magnetic properties. Herein, we report the preparation, structure, and magnetic properties of the triradical trianion of a shape-persistent chiral equilateral molecular triangle having three naphthalene-1,4:5,8-bis(dicarboximide)s ((+)-NDI-Δ
Publisher: American Chemical Society (ACS)
Date: 24-05-2021
DOI: 10.1021/JACS.1C01493
Publisher: American Chemical Society (ACS)
Date: 24-04-2017
DOI: 10.1021/JACS.7B01209
Abstract: Organic rechargeable batteries, composed of redox-active molecules, are emerging as candidates for the next generation of energy storage materials because of their large specific capacities, cost effectiveness, and the abundance of organic precursors, when compared with conventional lithium-ion batteries. Although redox-active molecules often display multiple redox states, precise control of a molecule's redox potential, leading to a single output voltage in a battery, remains a fundamental challenge in this popular field of research. By combining macrocyclic chemistry with density functional theory calculations (DFT), we have identified a structural motif that more effectively delocalizes electrons during lithiation events in battery operations-namely, through-space electron delocalization in triangular macrocyclic molecules that exhibit a single well-defined voltage profile-compared to the discrete multiple voltage plateaus observed for a homologous macrocyclic dimer and an acyclic derivative of pyromellitic diimide (PMDI). The triangular macrocycle, incorporating three PMDI units in close proximity to one another, exhibits a single output voltage at 2.33 V, compared with two peaks at (i) 2.2 and 1.95-1.60 V for reduction and (ii) 1.60-1.95 and 2.37 V for oxidation of the acyclic PMDI derivative. By investigating the two cyclic derivatives with different conformational dispositions of their PMDI units and the acyclic PMDI derivative, we identified noticeable changes in interactions between the PMDI units in the two cyclic derivatives under reducing conditions, as determined by differential pulse voltammetry, solution-state spectroelectrochemistry, and variable-temperature UV-Vis spectra. The numbers and relative geometries of the PMDI units are found to alter the voltage profile of the active materials significantly during galvanostatic measurements, resulting in a desirable single plateau for the triangular macrocycle. The present investigation reveals that understanding and controlling the relative conformational dispositions of redox-active units in macrocycles are key to achieving high energy density and long cycle-life electrodes for organic rechargeable batteries.
Publisher: Wiley
Date: 08-09-2016
Publisher: Wiley
Date: 22-11-2016
Abstract: A fullerene-based photosensitizer is incorporated postsynthetically into a Zr
Publisher: Wiley
Date: 22-10-2021
Abstract: Constructing multicolor photoluminescent materials with tunable properties is an attractive research objective on account of their abundant applications in materials science and biomedical engineering. By comparison with covalent synthesis, supramolecular chemistry has provided a more competitive and promising strategy for the production of organic materials and the regulation of their photophysical properties. By taking advantage of dynamic and reversible noncovalent bonding interactions, supramolecular strategies can, not only simplify the design and fabrication of organic materials, but can also endow them with dynamic reversibility and stimuli responsiveness, making it much easier to adjust the superstructures and properties of the materials. Occasionally, it is possible to introduce emergent properties into these materials, which are absent in their precursor compounds, broadening their potential applications. In an attempt to highlight the state‐of‐the‐art noncovalent strategies available for the construction of smart luminescent materials, an overview of color‐tunable materials is presented in this Review, with the emphasis being placed on the ex les drawn from host–guest complexes, supramolecular assemblies and crystalline materials. The noncovalent synthesis of room‐temperature phosphorescent materials and the modulation of their luminescent properties are also described. Finally, future directions and scientific challenges in the emergent field of color‐tunable supramolecular emissive materials are discussed.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 12-06-2020
Abstract: Rotaxanes consist of molecular rings threaded on a central axle. Most approaches to their synthesis have focused on introducing a single ring per axle. Qiu et al. now report a systematic approach to threading up to 10 adjacent rings consecutively. The axle's end groups were constructed to attract free-floating rings when reduced and then to push those rings toward the center upon oxidation. Products of each successive reduction-oxidation cycle were characterized by nuclear magnetic resonance spectroscopy and mass spectrometry. Science , this issue p. 1247
Publisher: American Chemical Society (ACS)
Date: 04-2021
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0QM00022A
Abstract: Hypothetical transmembrane rotaxane as a model for trajectory thermodynamic theory of synthetic molecular pumps.
Publisher: Wiley
Date: 07-09-2021
Abstract: Complexation between a viologen radical cation ( V .+ ) and cyclobis(paraquat‐ p ‐phenylene) diradical dication ( CBPQT 2(.+) ) has been investigated and utilized extensively in the construction of mechanically interlocked molecules (MIMs) and artificial molecular machines (AMMs). The selective recognition of a pair of V .+ using radical‐pairing interactions, however, remains a formidable challenge. Herein, we report the efficient encapsulation of two methyl viologen radical cations ( MV .+ ) in a size‐matched bisradical dicationic host — namely, cyclobis(paraquat‐2,6‐naphthalene) 2(.+) , i.e., CBPQN 2(.+) . Central to this dual recognition process was the choice of 2,6‐bismethylenenaphthalene linkers for incorporation into the bisradical dicationic host. They provide the space between the two bipyridinium radical cations in CBPQN 2(.+) suitable for binding two MV .+ with relatively short (3.05–3.25 Å) radical‐pairing distances. The size‐matched bisradical dicationic host was found to exhibit highly selective and cooperative association with the two MV .+ in MeCN at room temperature. The formation of the tetrakisradical tetracationic inclusion complex — namely, [ (MV) 2 ⊂ CBPQN ] 4( .+) – in MeCN was confirmed by VT 1 H NMR, as well as by EPR spectroscopy. The solid‐state superstructure of [ (MV) 2 ⊂ CBPQN ] 4( .+) reveals an uneven distribution of the binding distances (3.05, 3.24, 3.05 Å) between the three different V .+ , suggesting that localization of the radical‐pairing interactions has a strong influence on the packing of the two MV .+ inside the bisradical dicationic host. Our findings constitute a rare ex le of binding two radical guests with high affinity and cooperativity using host‐guest radical‐pairing interactions. Moreover, they open up possibilities of harnessing the tetrakisradical tetracationic inclusion complex as a new, orthogonal and redox‐switchable recognition motif for the construction of MIMs and AMMs.
Publisher: American Chemical Society (ACS)
Date: 13-01-2020
DOI: 10.1021/JACS.9B12828
Abstract: Protection of enzymes with synthetic materials is a viable strategy to stabilize, and hence to retain, the reactivity of these highly active biomolecules in non-native environments. Active synthetic supports, coupled to encapsulated enzymes, can enable efficient cascade reactions which are necessary for processes like light-driven CO
Publisher: Springer Science and Business Media LLC
Date: 10-12-2018
DOI: 10.1038/S41467-018-07673-1
Abstract: The host-guest recognition between two macrocycles to form hierarchical non-intertwined ring-in-ring assemblies remains an interesting and challenging target in noncovalent synthesis. Herein, we report the design and characterization of a box-in-box assembly on the basis of host-guest radical-pairing interactions between two rigid diradical dicationic cyclophanes. One striking feature of the box-in-box complex is its ability to host various 1,4-disubstituted benzene derivatives inside as a third component in the cavity of the smaller of the two diradical dicationic cyclophanes to produce hierarchical Russian doll like assemblies. These results highlight the utility of matching the dimensions of two different cyclophanes as an efficient approach for developing new hybrid supramolecular assemblies with radical-paired ring-in-ring complexes and smaller neutral guest molecules.
Publisher: American Chemical Society (ACS)
Date: 09-2017
DOI: 10.1021/JACS.7B06857
Abstract: Radical templation centered around a heterotrisradical tricationic inclusion complex DB
Publisher: American Chemical Society (ACS)
Date: 05-04-2023
DOI: 10.1021/JACS.2C13576
Publisher: American Chemical Society (ACS)
Date: 20-10-2022
DOI: 10.1021/JACS.2C08144
Abstract: Despite the advances in host-guest chemistry, macrocyclic hosts with deep cavities are far from abundant among the large number of wholly synthetic hosts described in the literature. Herein, we describe the design and synthesis of two new tubular hosts, namely, corral[4]arene and corral[5]arene. The former has been isolated and characterized as two conformational diastereoisomers, one is centrosymmetric and the other asymmetric. The latter, a fivefold symmetrical and flexible host, has also been investigated in detail. It is composed of five 4,4'-dimethoxybiphenyl units bridged by ethynylene linkers at their 2,2'-positions and adopts a pentagonal conformation with a tubular-shaped cavity in the presence of guests. This structure endows corral[5]arene not only with a conjugated backbone, capable of bright fluorescent emission (quantum yield, 56%), but also a deep π-electron-rich aromatic cavity with remarkable conformational flexibility. The adaptive cavity of corral[5]arene allows it to accommodate a wide range of neutral and positively charged electron-deficient guests with different molecular sizes and shapes. Binding constants between this host and these guests in three different nonpolar organic solvents lie in the range of 10
Publisher: Wiley
Date: 30-06-2021
Abstract: The recognition and separation of anions attracts attention from chemists, materials scientists, and engineers. Employing exo‐binding of artificial macrocycles to selectively recognize anions remains a challenge in supramolecular chemistry. We report the instantaneous co‐crystallization and concomitant co‐precipitation between [PtCl 6 ] 2− dianions and cucurbit[6]uril, which relies on the selective recognition of these dianions through noncovalent bonding interactions on the outer surface of cucurbit[6]uril. The selective [PtCl 6 ] 2− dianion recognition is driven by weak [Pt−Cl⋅⋅⋅H−C] hydrogen bonding and [Pt−Cl⋅⋅⋅C=O] ion–dipole interactions. The synthetic protocol is highly selective. Recognition is not observed in combinations between cucurbit[6]uril and six other Pt‐ and Pd‐ or Rh‐based chloride anions. We also demonstrated that cucurbit[6]uril is able to separate selectively [PtCl 6 ] 2− dianions from a mixture of [PtCl 6 ] 2− , [PdCl 4 ] 2− , and [RhCl 6 ] 3− anions. This protocol could be exploited to recover platinum from spent vehicular three‐way catalytic converters and other platinum‐bearing metal waste.
Publisher: Wiley
Date: 21-04-2017
Abstract: We report the synthesis of a tetracationic macrocycle which contains two N,N'-bis(methylene)naphthalenediimide units inserted in between the pyridinium rings of the bipyridinium units in cyclobis(paraquat-p-phenylene) (CBPQT
Publisher: American Chemical Society (ACS)
Date: 26-11-2018
DOI: 10.1021/JACS.8B10526
Abstract: Designing macrocycles with appropriate molecular recognition features that allow for the integration of suitable external stimuli to control host-guest processes is a challenging endeavor which enables molecular containers to solubilize, stabilize, and separate chemical entities in an externally controllable manner. Herein, we introduce photo- and thermal-responsive elements into a semi-rigid tetracationic cyclophane, OPVEx
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7CS00185A
Abstract: This review features the progress made in the development of macrocycles since Pedersen's ground-breaking discovery of the crown ethers in 1967.
Publisher: American Chemical Society (ACS)
Date: 12-04-2017
DOI: 10.1021/ACS.MOLPHARMACEUT.7B00168
Abstract: Although ibuprofen is one of the most widely used nonsteroidal anti-inflammatory drugs (NSAIDs), it exhibits poor solubility in aqueous and physiological environments as a free acid. In order to improve its oral bioavailability and rate of uptake, extensive research into the development of new formulations of ibuprofen has been undertaken, including the use of excipients as well as ibuprofen salts, such as ibuprofen lysinate and ibuprofen, sodium salt. The ultimate goals of these studies are to reduce the time required for maximum uptake of ibuprofen, as this period of time is directly proportional to the rate of onset of analgesic/anti-inflammatory effects, and to increase the half-life of the drug within the body that is, the duration of action of the effects of the drug. Herein, we present a pharmaceutical cocrystal of ibuprofen and the biocompatible metal-organic framework called CD-MOF. This metal-organic framework (MOF) is based upon γ-cyclodextrin (γ-CD) tori that are coordinated to alkali metal cations (e.g., K
Publisher: Wiley
Date: 16-08-2017
Publisher: American Chemical Society (ACS)
Date: 12-02-2021
DOI: 10.1021/JACS.0C12664
Publisher: Proceedings of the National Academy of Sciences
Date: 22-06-2020
Abstract: Electronic waste, also called e-waste, is rapidly becoming a major industrial hazard because of the increased use of circuits and screens. With the right technology, however, this waste could become a sustainable source for precious metals. Such a solution requires selectivity toward the precious metals, as this characteristic is even more important than capacity. A porphyrin-based porous polymer with selective binding shows remarkable selectivity and a reductive mechanism, a combination which makes for record-high recycling of precious metals––particularly gold––from e-waste.
Publisher: Springer Science and Business Media LLC
Date: 02-12-2022
Publisher: Springer Science and Business Media LLC
Date: 24-06-2022
Publisher: American Chemical Society (ACS)
Date: 31-07-2020
DOI: 10.1021/JACS.0C06663
Publisher: American Chemical Society (ACS)
Date: 12-11-2020
DOI: 10.1021/JACS.0C09896
Publisher: Springer Science and Business Media LLC
Date: 15-04-2021
DOI: 10.1038/S41557-021-00671-9
Abstract: Aromatic hydrocarbon belts (AHCBs) have fascinated scientists for over half a century because of their aesthetically appealing structures and potential applications in the field of carbon nanotechnology. One of the enduring challenges in synthesizing AHCBs is how do we cope with the build-up of energy in the highly strained structures during their synthesis? Successful preparations of AHCBs offer the prospect of providing well-defined templates for the growth of uniform single-walled carbon nanotubes-a long-standing interest in nanocarbon science. In this Review, we revisit the protracted historical background involving the rational design and synthesis of AHCBs and highlight some of the more recent breakthroughs, with emphasis being placed on the different strategies that have been used for building up curved and fused benzenoid rings into molecular belts. We also discuss the scientific challenges in this fledgling field and provide some pointers as to what could transpire in years to come.
Publisher: Wiley
Date: 24-11-2022
Abstract: The tetracationic cyclophane, cyclobis(paraquat‐ p ‐phenylene), also known as the little blue box, constitutes a modular receptor that has facilitated the discovery of many host–guest complexes and mechanically interlocked molecules during the past 35 years. Its versatility in binding small π‐donors in its tetracationic state, as well as forming trisradical tricationic complexes with viologen radical cations in its doubly reduced bisradical dicationic state, renders it valuable for the construction of various stimuli‐responsive materials. Since the first reports in 1988, the little blue box has been featured in over 500 publications in the literature. All this research activity would not have been possible without the seminal contributions carried out by Siegfried Hünig, who not only pioneered the syntheses of viologen‐containing cyclophanes, but also revealed their rich redox chemistry in addition to their ability to undergo intramolecular π‐dimerization. This Review describes how his pioneering research led to the design and synthesis of the little blue box, and how this redox‐active host evolved into the key component of molecular shuttles, switches, and machines.
Publisher: American Chemical Society (ACS)
Date: 16-01-2023
DOI: 10.1021/JACS.2C11425
Publisher: American Chemical Society (ACS)
Date: 17-08-2020
DOI: 10.1021/JACS.0C07877
Publisher: American Chemical Society (ACS)
Date: 10-07-2020
Publisher: American Chemical Society (ACS)
Date: 25-04-2023
DOI: 10.1021/JACS.2C13846
Publisher: Wiley
Date: 16-08-2017
Abstract: Chemistry welcomes a new bond: The mechanical bond has endowed molecules with component parts whose movements can be controlled and monitored. In his Nobel Lecture, J. F. Stoddart describes how being able to template the formation of mechanically interlocked molecules has led to the design and synthesis of shuttles, switches, and machines at the nanoscale.
Publisher: American Chemical Society (ACS)
Date: 03-08-2017
DOI: 10.1021/JACS.7B06287
Abstract: Co-crystallization of K
Publisher: American Chemical Society (ACS)
Date: 18-02-2022
DOI: 10.1021/JACS.1C12480
Abstract: Artificial molecular pumps (AMPs), inspired by the active cellular transport exhibited in biological systems, enable cargoes to undergo unidirectional motion, courtesy of molecular ratchet mechanisms in the presence of energy sources. Significant progress has been achieved, using alternatively radical interactions and Coulombic repulsive forces to create working AMPs. In an attempt to widen the range of these AMPs, we have explored the effect of molecular pumping on the photophysical properties of a collecting chain on a dumbbell incorporating a centrally located pyrene fluorophore and two terminal pumping cassettes. The AMP discussed here sequesters two tetracationic cyclophanes from the solution, generating a [3]rotaxane in which the fluorescence of the dumbbell is quenched. The research reported in this Article demonstrates that the use of pumping cassettes allows us to generate the [3]rotaxane in which the photophysical properties of fluorophores can be modified in a manner that cannot be achieved with a mixture of the dumbbell and ring components of the rotaxane on account of their weak binding in solution.
Publisher: American Chemical Society (ACS)
Date: 14-08-2017
Publisher: Proceedings of the National Academy of Sciences
Date: 15-03-2022
Abstract: During the past decades, the development of efficient methodologies for the creation of mechanically interlocked molecules (MIMs), such as catenanes and rotaxanes, has not only laid the foundation for the design and syntheses of artificial molecular machines (AMMs) but also opened up new research opportunities in multiple disciplines, ranging from contemporary chemistry to materials science. In this study, we describe a suitane-based strategy for the construction of three-dimensional (3D) catenanes, a subset of MIMs that are far from easy to make. Together with synthetic methodologies based on the metal coordination and dynamic covalent chemistry, this approach brings us one step closer to realizing routine syntheses of 3D catenanes.
Publisher: Wiley
Date: 22-08-2022
Abstract: Here, we report an approach to the synthesis of highly charged enantiopure cyclophanes by the insertion of axially chiral enantiomeric binaphthyl fluorophores into the constitutions of pyridinium‐based macrocycles. Remarkably, these fluorescent tetracationic cyclophanes exhibit a significant AIE compared to their neutral optically active binaphthyl precursors. A combination of theoretical calculations and time‐resolved spectroscopy reveal that the AIE originates from limited torsional vibrations associated with the axes of chirality present in the chiral enantiomeric binaphthyl units and the fine‐tuning of their electronic landscape when incorporated within the cyclophane structure. Furthermore, these highly charged enantiopure cyclophanes display CPL responses both in solution and in the aggregated state. This unique duality of AIE and CPL in these tetracationic cyclophanes is destined to be of major importance in future development of photonic devices and bio‐applications.
Publisher: American Chemical Society (ACS)
Date: 11-12-2018
DOI: 10.1021/JACS.8B11201
Abstract: The development of rigid covalent chiroptical organic materials, with multiple, readily available redox states, which exhibit high photoluminescence, is of particular importance in relation to both organic electronics and photonics. The chemically stable, thermally robust, and redox-active perylene diimide (PDI) fluorophores have received ever-increasing attention owing to their excellent fluorescence quantum yields in solution. Planar PDI derivatives, however, generally suffer from aggregation-caused emission quenching in the solid state. Herein, we report on the design and synthesis of two chiral isosceles triangles, wherein one PDI fluorophore and two pyromellitic diimide (PMDI) or naphthalene diimide (NDI) units are arranged in a rigid cyclic triangular geometry. The optical, electronic, and magnetic properties of the rigid isosceles triangles are fully characterized by a combination of optical spectroscopies, X-ray diffraction (XRD), cyclic voltammetry, and computational modeling techniques. Single-crystal XRD analysis shows that both isosceles triangles form discrete, nearly cofacial PDI-PDI π-dimers in the solid state. While the triangles exhibit fluorescence quantum yields of almost unity in solution, the dimers in the solid state exhibit very weak-yet at least an order of magnitude higher-excimer fluorescence yield in comparison with the almost completely quenched fluorescence of a reference PDI. The triangle containing both NDI and PDI subunits shows superior intramolecular energy transfer from the lowest excited singlet state of the NDI to that of the PDI subunit. Cyclic voltammetry suggests that both isosceles triangles exhibit multiple, easily accessible, and reversible redox states. Applications beckon in arenas related to molecular optoelectronic devices.
Publisher: Wiley
Date: 21-04-2017
Publisher: American Chemical Society (ACS)
Date: 11-10-2019
DOI: 10.1021/JACS.9B09756
Abstract: The design and synthesis of artificial molecular switches (AMSs) displaying architectures of increased complexity would constitute significant progress in meeting the challenging task of realizing artificial molecular machines (AMMs). Here, we report the synthesis and characterization of a molecular shuttle composed of a cyclobis(paraquat-4,4'-biphenylene) cyclophane ring and a dumbbell incorporating a cyclobis(paraquat-
Publisher: Proceedings of the National Academy of Sciences
Date: 18-09-2018
Publisher: Wiley
Date: 28-06-2018
Publisher: Wiley
Date: 17-05-2021
Abstract: The coordination‐driven self‐assembly of organometallic half‐sandwich iridium(III)‐ and rhodium(III)‐based building blocks with asymmetric ambidentate pyridyl‐carboxylate ligands is described. Despite the potential for obtaining a statistical mixture of multiple products, D 2 symmetric octanuclear cages were formed selectively by taking advantage of the electronic effects emanating from the two types of chelating sites – ( O , O’ ) and ( N , N’ ) – on the tetranuclear building blocks. The metal sources and the lengths of bridging ligands influence the selectivity of the self‐assembly. Experimental observations, supported by computational studies, suggest that the D 2 symmetric cages are the thermodynamically favored products. Overall, the results underline the importance of electronic effects on the selectivity of coordination‐driven self‐assembly, and demonstrate that asymmetric ambidentate ligands can be used to control the design of discrete supramolecular coordination complexes.
Publisher: American Chemical Society (ACS)
Date: 09-06-2023
DOI: 10.1021/JACS.3C02266
Publisher: Wiley
Date: 14-10-2021
Publisher: American Chemical Society (ACS)
Date: 11-06-2019
DOI: 10.1021/JACS.9B04198
Abstract: Making metal-organic frameworks (MOFs) that are stabilized in nonpolar media is not as straightforward as making their inorganic nanoparticle counterparts, since surfactants penetrate through the porous structures or dissolve the secondary building units (SBUs) through ligand-exchange linker modulator mechanisms. Herein, we report that calixarenes stabilize UIO-66 nanoparticles effectively by remaining outside the grains through size exclusion, without pores becoming blocked, all the while providing hiphilicity that permits the formation of stable colloidal dispersions with much narrower size distributions. Using the UIO-66 dispersed solutions, we show that smooth films from an otherwise immiscible polystyrene can be made feasibly.
Publisher: American Chemical Society (ACS)
Date: 14-01-2020
DOI: 10.1021/JACS.9B12527
Abstract: A class of γ-cyclodextrin-containing hybrid frameworks (CD-HFs) has been synthesized, employing γ-cyclodextrin (γ-CD) as the primary building blocks, along with 4-methoxysalicylate (4-MS
Publisher: American Chemical Society (ACS)
Date: 31-08-2020
DOI: 10.1021/JACS.0C05445
Publisher: Springer Science and Business Media LLC
Date: 25-02-2019
Publisher: American Chemical Society (ACS)
Date: 04-09-2020
DOI: 10.1021/JACS.0C07745
Publisher: American Chemical Society (ACS)
Date: 29-05-2020
DOI: 10.1021/JACS.0C03701
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United States of America
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Fraser Stoddart.