ORCID Profile
0000-0003-3088-6327
Current Organisations
Amity University
,
Technische Universität Dresden
,
University of Würzburg
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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 4 Research Topics
ANZSRC Field of Research (FoR)
Nanotechnology | Biological Physics | Nanoelectronics
ANZSRC Socio-Economic Objective (SEO)
Related Links
Publications
Planar four-coordinate boron: A single, flat boron atom as a ligand for four metals
Publisher: Wiley
Date: 17-01-2012
Comment éviter la formation d’embouteillages de moteurs moléculaires lors du trafic intracellulaire ?
Publisher: EDP Sciences
Date: 12-2012
Isolation of the key intermediates of base-promoted borylene–carbonyl coupling reactions
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4SC00183D
Desymmetrizing Electron-Deficient Diboranes(4): Diverse Products and Their Reactivity
Publisher: Wiley
Date: 12-08-2016
Abstract: A comprehensive study of the reactivity of Lewis bases with dihalodiboranes(4) is presented. Diaryldihalodiboranes provide rearranged monoadducts when treated with cyclic (alkyl)(amino)carbenes, but halide-bridged adducts when treated with a range of pyridyl bases. Alternatively, the combination of diaminodihalodiboranes with strong carbene donors leads to boraborenium salts. The reduction and halide-abstraction reactivity of these adducts was also explored, leading to intramolecular C-H activation and the first 1,2-bis(borenium) dication.
The Kinesin-Related Protein MCAK Is a Microtubule Depolymerase that Forms an ATP-Hydrolyzing Complex at Microtubule Ends
Publisher: Elsevier BV
Date: 02-2003
DOI: 10.1016/S1097-2765(03)00049-2
Abstract: MCAK belongs to the Kin I subfamily of kinesin-related proteins, a unique group of motor proteins that are not motile but instead destabilize microtubules. We show that MCAK is an ATPase that catalytically depolymerizes microtubules by accelerating, 100-fold, the rate of dissociation of tubulin from microtubule ends. MCAK has one high-affinity binding site per protofilament end, which, when occupied, has both the depolymerase and ATPase activities. MCAK targets protofilament ends very rapidly (on-rate 54 micro M(-1).s(-1)), perhaps by diffusion along the microtubule lattice, and, once there, removes approximately 20 tubulin dimers at a rate of 1 s(-1). We propose that up to 14 MCAK dimers assemble at the end of a microtubule to form an ATP-hydrolyzing complex that processively depolymerizes the microtubule.
Cyclization of a 1,4-diborabutadiene ligand with both atoms of CO
Publisher: Wiley
Date: 27-02-2015
Abstract: A 1,4-dibora-1,3-butadiene iron complex was successfully synthesized through the stoichiometric reaction of an iron bis(borylene) complex with diphenylacetylene. This complex was treated with CO and PMe3 , which led to the formation of an unusual six-membered B2 C3 O ylidic ring bound to both the PMe3 group and zerovalent iron center. The reaction is a very rare ex le of the incorporation of both atoms of CO into a ring system.
The distance that kinesin-1 holds its cargo from the microtubule surface measured by fluorescence interference contrast microscopy
Publisher: Proceedings of the National Academy of Sciences
Date: 24-10-2006
Abstract: Kinesin-1 is a motor protein that carries cellular cargo such as membrane-bounded organelles along microtubules (MTs). The homodimeric motor molecule contains two N-terminal motor domains (the motor “heads”), a long coiled-coil domain (the “rod” or “stalk”), and two small globular “tail” domains. Much has been learned about how kinesin's heads step along a MT and how the tail is involved in cargo binding and autoinhibition. However, little is known about the role of the rod. Here, we investigate the extension of the rod during active transport by measuring the height at which MTs glide over a kinesin-coated surface in the presence of ATP. To perform height measurements with nanometer precision, we used fluorescence interference contrast microscopy, which is based on the self-interference of fluorescent light from objects near a reflecting surface. Using an in situ calibrating method, we determined that kinesin-1 molecules elevate gliding MTs 17 ± 2 nm (mean ± SEM) above the surface. When varying the composition of the surrounding nucleotides or removing the negatively charged -COOH termini of the MTs by subtilisin digestion, we found no significant changes in the measured distance. Even though this distance is significantly shorter than the contour length of the motor molecule (≈60 nm), it may be sufficient to prevent proteins bound to the MTs or prevent the organelles from interfering with transport.
Studying Kinesin Motors by Optical 3D-Nanometry in Gliding Motility Assays
Publisher: Elsevier
Date: 2010
Reversible Intramolecular Coupling of the Terminal Borylene and a Carbonyl Ligand of [Cp(CO)2MnBtBu]
Publisher: Wiley
Date: 20-11-2012
Abstract: Cyclic complex 2 with bridging carbonyl ligands was synthesized from a facile and reversible intermolecular carbonyl-borylene ligand coupling reaction at room temperature. Complex 2 exhibits an unprecedented coordination mode for boron-metal complexes, which is also reflected in its remarkable (11)B NMR chemical shift of -57.2 ppm. Findings from spectroscopic, X-ray, and computational studies are presented, along with a proposed mechanism.
Erratum: Trans-[Pt(BCat')Me(PCy3 )2 ]: An experimental case study of reductive elimination processes in Pt-boryls through associative mechanisms (Chemistry - A European Journal (2011) 17 (11828-11837) DOI: 10.1002/chem.201101823)
Publisher: Wiley
Date: 25-10-2011
The η3-furfuryl ligand: Plausible catalytic intermediates and heterocyclic η3-benzyl analogues with superior binding ability
Publisher: American Chemical Society (ACS)
Date: 24-09-2010
DOI: 10.1021/OM100786H
Reactivity of Lewis basic platinum complexes towards fluoroboranes
Publisher: Wiley
Date: 15-05-2013
Abstract: We herein report detailed investigations into the interaction of Lewis acidic fluoroboranes, for ex le BF2Pf (Pf=perfluorophenyl) and BF2Ar(F) (Ar(F)=3,5-bis(trifluoromethyl)phenyl), with Lewis basic platinum complexes such as [Pt(PEt3)3] and [Pt(PCy3)2] (Cy=cyclohexyl). Two presumed Lewis adducts could be identified in solution and corresponding secondary products of these Lewis adducts were characterized in the solid state. Furthermore, the concept of frustrated Lewis pairs (FLP) was applied to the activation of ethene in the system [Pt(BPf3)(CH2CH2)(dcpp)] (dcpp=1,3-bis(dicyclohexylphosphino)propane Pf=perfluorophenyl). Finally, DFT calculations were performed to determine the interaction between the platinum-centered Lewis bases and the boron-centered Lewis acids. Additionally, several possible mechanisms for the oxidative addition of the boranes BF3, BCl3, and BF2Ar(F) to the model complex [Pt(PMe3)2] are presented.
Observation of elementary steps in the catalytic borane dehydrocoupling reaction
Publisher: Wiley
Date: 15-06-2012
Side-on coordination of boryl and borylene complexes to cationic coinage metal fragments
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5SC00211G
Abstract: The M-(η 2 -BMn) complex [(η 5 -C 5 H 5 )(OC) 2 Mn{μ-B(Cl)( t Bu)Au(PPh 3 )}] ( 2 ) can be functionalized via halide substitution reactions to afford isostructural complexes [(η 5 -C 5 H 5 )(OC) 2 Mn{μ-B(R)( t Bu)Au(PPh 3 )}] (R = Ph, CCPh and NCS).
Reactivity of a terminal chromium borylene complex towards olefins: Insertion of a borylene into a C-H bond
Publisher: Wiley
Date: 28-07-2008
Base-stabilized boryl and cationic haloborylene complexes of Iron
Publisher: Wiley
Date: 19-08-2013
Abstract: The synthesis of base-stabilized boryl and borylene complexes is reported. An N-heterocyclic carbene (NHC)-stabilized iron-dihydroboryl complex was prepared by two different routes including methane liberation and salt elimination. A range of base-stabilized iron-dichloroboryl complexes was prepared by addition of Lewis bases to boryl complexes. Base-stabilized, cationic monochloroborylene complexes were synthesized from these boryl complexes by halide abstraction by using weakly coordinating anions.
Cover Picture: Platinum trans-Bis(borirene) Complexes Displaying Coplanarity and Communication Across a Platinum Metal Center (Chem. Eur. J. 6/2015)
Publisher: Wiley
Date: 23-01-2015
Investigation of Steric Factors Involved in the Formation of Terminal Cationic Platinum Arylborylene Complexes
Publisher: American Chemical Society (ACS)
Date: 19-12-2015
DOI: 10.1021/OM501141G
Generation of a carbene-stabilized bora-borylene and its insertion into a C-H bond
Publisher: American Chemical Society (ACS)
Date: 04-11-2011
DOI: 10.1021/JA208372K
Abstract: A novel NHC adduct of a dihalodiborane(4), 1, is reduced by KC(8) with formation of the five-membered boracycle 2. The reaction most likely proceeds via C-H insertion of an intermediate NHC-stabilized free bora-borylene species.
Quaternizing diboranes(4): Highly divergent outcomes and an inorganic Wagner-Meerwein rearrangement
Publisher: American Chemical Society (ACS)
Date: 03-06-2013
DOI: 10.1021/JA403037K
Abstract: Apart from a few compounds under heavy use in organic chemistry, diboranes are relatively exotic and poorly understood. Recently, interest in these molecules has intensified with the advent of so-called "sp(2)-sp(3)" diboranes which exhibit useful reactivity toward organic substrates. In our hands, addition of Lewis bases to dihalodiorganyl diboranes(4) has previously shown some very surprising reactivity, including a substituent exchange between the boron atoms, and diboranes in which halide atoms bridge the B-B bond. Herein we have expanded the range of diborane(4) and Lewis base reaction partners, in the process uncovering three new reactivity patterns as well as some cases where mixtures are obtained. Trends are established for the preferential formation of certain products which rationalize the results based on electronic and steric effects. The substituent exchange, clearly based on an inorganic version of the well-known Wagner-Meerwein rearrangement, was also found to be an equilibrium reaction with the halide-bridged Lewis adducts on the other side.
Platinum trans-Bis(borirene) Complexes Displaying Coplanarity and Communication Across a Platinum Metal Center
Publisher: Wiley
Date: 09-12-2015
Stretching and Transporting DNA Molecules Using Motor Proteins
Publisher: American Chemical Society (ACS)
Date: 22-08-2003
DOI: 10.1021/NL034504H
σ-Donor–σ-acceptor plumbylene ligands: Synergic σ-donation between ambiphilic Pt0 and Pb
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2CC35777A
Abstract: Mono- and diplatinum plumbylene complexes are prepared in which the bonding comprises synergic σ donation between the Pt and Pb atoms. The bonding distinguishes the complexes from both the classical Fischer carbene bonding model and M→Pb dative-only bonding. The Pt-Pb bond of the monoplatinum complex is stable, while the diplatinum complex reversibly loses one Pt fragment.
Trihapto ligation of a borirene to a single metal atom: A heterocyclic analogue of the η3-cyclopropenyl ligand
Publisher: Wiley
Date: 06-05-2014
Abstract: The first ex le of a complex containing an η(3)-coordinated borirene ligand bound to a single metal atom was prepared by photolytic transfer of an arylborylene ligand to diphenylacetylene and loss of three CO ligands from the precursor. The η(3)-borirene complex possesses a chromium(0) atom which is also bound to one phenyl group in an η(6) fashion. The complex was isolated in 15% yield along with the corresponding metal-free borirene, which was isolated in 62% yield. The bonding between the chromium center and the borirene ring was studied computationally by DFT methods.
Dimanganese bridging borylene complexes and their reactions with unsaturated palladium(0) complexes - Syntheses, structures and calculated properties
Publisher: Wiley
Date: 09-2008
Cellular Motors for Molecular Manufacturing
Publisher: Wiley
Date: 2007
DOI: 10.1002/AR.20599
Abstract: Cells are composed of macromolecular structures of various sizes that act in idually or collectively to maintain their viability and perform their function within the organism. This review focuses on one structure, the microtubule, and one of the motor proteins that move along it, conventional kinesin (kinesin 1). Recent work on the cellular functions of kinesins, such as the organization of microtubules during cellular ision and the movement of the organelles and vesicles, offers insights into how biological motors might prove useful for organizing structures in engineered environments.
Borido complexes via intermetallic metalloborylene transfer
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C1CC13444B
Abstract: Intermetallic borylene transfer has been applied to synthesise new borido complexes. Starting from [{(η(5)-C(5)Me(5))Fe(CO)(2))}(μ-B){Cr(CO)(5)}] (1) the borylene moiety has been transferred successfully to different transition metal fragments. In the manner described, two new compounds have been fully characterised in solution and by X-ray crystallography.
An iridium N-heterocyclic carbene complex [IrCl(CO)2(NHC)] as a carbon monoxide-releasing molecule (CORM)
Publisher: Elsevier BV
Date: 04-2015
Diverse reactions of N-heterocyclic carbenes with an alkynylborane and isolation of a reactive zwitterionic borataallene
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3CC46947F
Abstract: Ethynyldimesitylborane (1) is synthesised via salt elimination and its reactivity towards NHCs is studied. Depending on their size, NHCs attack either at the boron atom or at the β-alkynyl carbon atom. Steric control over the reaction was probed by reactions with N-heterocyclic carbenes yielding a carbene-borane adduct (2), a 1-boraindane (3), and the first structurally characterised borataallene (4).
Parametric study on the dry sliding wear behaviour of AA6082–T6/TiB2 in situ composites using response surface methodology
Publisher: Springer Science and Business Media LLC
Date: 26-05-2018
Low-coordinate boride lisands: A true trimetalloborane
Publisher: Wiley
Date: 27-07-2009
Molecular crowding creates traffic jams of kinesin motors on microtubules
Publisher: Proceedings of the National Academy of Sciences
Date: 19-03-2012
Abstract: Despite the crowdedness of the interior of cells, microtubule-based motor proteins are able to deliver cargoes rapidly and reliably throughout the cytoplasm. We hypothesize that motor proteins may be adapted to operate in crowded environments by having molecular properties that prevent them from forming traffic jams. To test this hypothesis, we reconstituted high-density traffic of purified kinesin-8 motor protein, a highly processive motor with long end-residency time, along microtubules in a total internal-reflection fluorescence microscopy assay. We found that traffic jams, characterized by an abrupt increase in the density of motors with an associated abrupt decrease in motor speed, form even in the absence of other obstructing proteins. To determine the molecular properties that lead to jamming, we altered the concentration of motors, their processivity, and their rate of dissociation from microtubule ends. Traffic jams occurred when the motor density exceeded a critical value (density-induced jams) or when motor dissociation from the microtubule ends was so slow that it resulted in a pileup (bottleneck-induced jams). Through comparison of our experimental results with theoretical models and stochastic simulations, we characterized in detail under which conditions density- and bottleneck-induced traffic jams form or do not form. Our results indicate that transport kinesins, such as kinesin-1, may be evolutionarily adapted to avoid the formation of traffic jams by moving only with moderate processivity and dissociating rapidly from microtubule ends.
Dynamic, Reversible Oxidative Addition of Highly Polar Bonds to a Transition Metal
Publisher: American Chemical Society (ACS)
Date: 29-11-2016
DOI: 10.1021/JACS.6B10609
Abstract: The combination of Pt
Boron-Metallated Borirenes and Bis(Borirenes)
Publisher: Wiley
Date: 09-05-2016
Abstract: Heating the metalloborylene complex [{(η(5) -C5 Me5 )Fe(CO)2 }(μ-B){Cr(CO)5 }] with alkynes and diynes leads to the formation of B-metallated borirenes and a bis(B-metallated borirene) through formal transfer of the metalloborylene moiety [(η(5) -C5 Me5 )(OC)2 Fe(B:)]. By using this protocol, a range of B-metallated borirenes with electron-donating and electron-withdrawing substituents are prepared, and these are studied spectroscopically, structurally, and computationally. The yellow-orange color of the complexes is additionally explained through time-dependent density functional theory calculations.
The Highly Processive Kinesin-8, Kip3, Switches Microtubule Protofilaments with a Bias toward the Left
Publisher: Elsevier BV
Date: 07-2012
A metal-mediated boron-centred isomerisation reaction via C–H activation
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5CC07681A
Abstract: The terminal borylene ligand is activated by Lewis bases to couple with terminal carbonyl ligands reversibly, initially forming a kinetic coupling product, which isomerises via a borylene migratory insertion to a cyclopentadienyl ligand C–H bond.
A linear, anionic dimetalloborylene complex
Publisher: Wiley
Date: 20-06-2008
Direct Conversion from Terminal Borylene into Terminal Phosphinidene
Publisher: Wiley
Date: 13-09-2016
Abstract: The first terminal manganese phosphinidene complex was quantitatively synthesized from a terminal alkylborylene complex. Its structure and bonding, as well as the reaction mechanism, were investigated through a combination of experimental and computational studies.
Toward Transition-Metal-Templated Construction of Arylated B4 Chains by Dihydroborane Dehydrocoupling
Publisher: Wiley
Date: 09-12-2019
Platinum complexes containing pyramidalized germanium and tin Dihalide Ligands bound through δ, δ M=E Multiple Bonds
Publisher: Wiley
Date: 30-10-2014
Abstract: We present the isolation of the first mononuclear dihalogermylene, and mono- and dinuclear stannylene complexes of transition metals. These exhibit exceptionally pyramidalized Group 14 centers. Additionally, removal of the halide substituents from the Ge/Sn atom was successfully performed in two ways, halide abstraction and reduction, leading to a variety of unusual structural motifs.
Platinum trans-bis(borirene) complexes displaying coplanarity and communication across a platinum metal center
Publisher: Wiley
Date: 27-11-2015
Abstract: Ambient-temperature photolysis of the aminoborylene complex [(OC)5 Cr=B=N(SiMe3 )2 ] in the presence of a series of trans-bis(alkynyl)platinum(II) precursors of the type trans-[Pt(CCAr)2 (PEt3 )2 ] (Ar=Ph, p-C6 H4 OMe, and p-C6 H4 CF3 ) successfully leads to twofold transfer of the borylene moiety [:B=N(SiMe3 )2 ] onto the alkyne functionalities. The alkynyl precursors and resultant bis(borirene)platinum(II) complexes formed are of the type trans-[Pt(B{=N(SiMe3 )2 }C=CAr)2 (PEt3 )2 ] (Ar=Ph, p-C6 H4 OMe, and p-C6 H4 CF3 ). These species have all been successfully characterized by NMR, IR, and UV/Vis spectroscopy as well as by elemental analysis. Single-crystal X-ray diffraction has verified that these trans-bis(borirene)platinum(II) complexes display coplanarity between the twin three-membered rings across the platinum core in the solid state and stand as the first ex les of coplanar conformations of twin borirene systems. These complexes were modeled using density functional theory (DFT), providing information helpful in determining the ability of the transition metal core to interact with each in idual borirene ring system and allowing for the observed coplanarity of these rings in the solid state. This proposed transition metal interaction with the twin borirene systems is manifested in the electronic characterization of these borirene species, which display ergent photophysical UV/Vis spectroscopic profiles compared to a previously published mono(borirene)platinum(II) complex.
η 3-furfuryl and η 3-thienyl complexes of palladium and platinum of relevance to the functionalization of biomass-derived furans
Publisher: American Chemical Society (ACS)
Date: 30-07-2012
DOI: 10.1021/OM300568Z
Kinesin-8 Motors Act Cooperatively to Mediate Length-Dependent Microtubule Depolymerization
Publisher: Elsevier BV
Date: 09-2009
DOI: 10.1016/J.CELL.2009.07.032
Abstract: Motor proteins in the kinesin-8 family depolymerize microtubules in a length-dependent manner that may be crucial for controlling the length of organelles such as the mitotic spindle. We used single-molecule microscopy to understand the mechanism of length-dependent depolymerization by the budding yeast kinesin-8, Kip3p. We found that after binding at a random position on a microtubule and walking to the plus end, an in idual Kip3p molecule pauses there until an incoming Kip3p molecule bumps it off. Kip3p dissociation is accompanied by removal of just one or two tubulin dimers (on average). Such a cooperative mechanism leads to a depolymerization rate that is proportional to the flux of motors to the microtubule end and accounts for the length dependence of depolymerization. This type of feedback between length and disassembly may serve as a model for understanding how an ensemble of molecules can measure and control polymer length.
Detection of fractional steps in cargo movement by the collective operation of kinesin-1 motors
Publisher: Proceedings of the National Academy of Sciences
Date: 26-06-2007
Abstract: The stepping behavior of single kinesin-1 motor proteins has been studied in great detail. However, in cells, these motors often do not work alone but rather function in small groups when they transport cellular cargo. Until now, the cooperative interactions between motors in such groups were poorly understood. A fundamental question is whether two or more motors that move the same cargo step in synchrony, producing the same step size as a single motor, or whether the step size of the cargo movement varies. To answer this question, we performed in vitro gliding motility assays, where microtubules coated with quantum dots were driven over a glass surface by a known number of kinesin-1 motors. The motion of in idual microtubules was then tracked with nanometer precision. In the case of transport by two kinesin-1 motors, we found successive 4-nm steps, corresponding to half the step size of a single motor. Dwell-time analysis did not reveal any coordination, in the sense of alternate stepping, between the motors. When three motors interacted in collective transport, we identified distinct forward and backward jumps on the order of 10 nm. The existence of the fractional steps as well as the distinct jumps illustrate a lack of synchronization and has implications for the analysis of motor-driven organelle movement investigated in vivo .
Trans-[Pt(BCat′)Me(PCy3 )2 ]: An experimental case study of reductive elimination processes in Pt-boryls through associative mechanisms
Publisher: Wiley
Date: 07-09-2011
Abstract: A stable trans-(alkyl)(boryl) platinum complex trans-[Pt(BCat')Me(PCy(3))(2)] (Cat'=Cat-4-tBu Cy=cyclohexyl=C(6)H(11)) was synthesised by salt metathesis reaction of trans-[Pt(BCat')Br(PCy(3))(2)] with LiMe and was fully characterised. Investigation of the reactivity of the title compound showed complete reductive elimination of Cat'BMe at 80 °C within four weeks. This process may be accelerated by the addition of a variety of alkynes, thereby leading to the formation of the corresponding η(2) -alkyne platinum complexes, of which [Pt(η(2)-MeCCMe)(PCy(3))(2)] was characterised by X-ray crystallography. Conversion of the trans-configured title compound to a cis derivative remained unsuccessful due to an instantaneous reductive elimination process during the reaction with chelating phosphines. Treatment of trans-[Pt(BCat')Me(PCy(3))(2)] with Cat(2)B(2) led to the formation of CatBMe and Cat'BMe. In the course of further investigations into this reaction, indications for two indistinguishable reaction mechanisms were found: 1) associative formation of a six-coordinate platinum centre prior to reductive elimination and 2) σ-bond metathesis of B-B and C-Pt bonds. Mechanism 1 provides a straightforward explanation for the formation of both methylboranes. Scrambling of diboranes(4) Cat(2)B(2) and Cat'(2)B(2) in the presence of [Pt(PCy(3))(2)], fully reductive elimination of CatBMe or Cat'BMe from trans-[Pt(BCat')Me(PCy(3))(2)] in the presence of sub-stoichiometric amounts of Cat(2)B(2), and evidence for the reversibility of the oxidative addition of Cat(2)B(2) to [Pt(PCy(3))(2)] all support mechanism 2, which consists of sequential equilibria reactions. Furthermore, the solid-state molecular structure of cis-[Pt(BCat)(2)(PCy(3))(2)] and cis-[Pt(BCat')(2)(PCy(3))(2)] were investigated. The remarkably short B-B separations in both bis(boryl) complexes suggest that the two boryl ligands in each case are more loosely bound to the Pt(II) centre than in related bis(boryl) species.
Partially and fully reversible solvation-controlled borylene swapping and metal-only Lewis pair formation
Publisher: American Chemical Society (ACS)
Date: 20-06-2014
DOI: 10.1021/OM5002414
Multiple complexation of CO and related ligands to a main-group element
Publisher: Springer Science and Business Media LLC
Date: 06-2015
DOI: 10.1038/NATURE14489
Abstract: The ability of an atom or molecular fragment to bind multiple carbon monoxide (CO) molecules to form multicarbonyl adducts is a fundamental trait of transition metals. Transition-metal carbonyl complexes are vital to industry, appear naturally in the active sites of a number of enzymes (such as hydrogenases), are promising therapeutic agents, and have even been observed in interstellar dust clouds. Despite the wealth of established transition-metal multicarbonyl complexes, no elements outside groups 4 to 12 of the periodic table have yet been shown to react directly with two or more CO units to form stable multicarbonyl adducts. Here we present the synthesis of a borylene dicarbonyl complex, the first multicarbonyl complex of a main-group element prepared using CO. The compound is additionally stable towards ambient air and moisture. The synthetic strategy used--liberation of a borylene ligand from a transition metal using donor ligands--is broadly applicable, leading to a number of unprecedented monovalent boron species with different Lewis basic groups. The similarity of these compounds to conventional transition-metal carbonyl complexes is demonstrated by photolytic liberation of CO and subsequent intramolecular carbon-carbon bond activation.
Strained ansa half-sandwich complexes of ruthenium and osmium and a non-iron metallopolymer by ring-opening polymerization
Publisher: American Chemical Society (ACS)
Date: 26-03-2014
DOI: 10.1021/OM500111R
1,2-Halosilane vs. 1,2-alkylborane elimination from (boryl)(silyl) complexes of iron: Switching between borylenes and silylenes just by changing the alkyl group
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5CC06425B
Abstract: The results present a new elimination reaction, the 1,2-alkylborane elimination, as a new route to silylene complexes.
Monohaloboryls (BHX-) as bridging ligands: Observable dinuclear σ-(halo)boranyl intermediates in the synthesis of metalloborylenes
Publisher: Wiley
Date: 20-01-2012
Abstract: Upon treating transition-metal-dihaloboryl complexes of the form [L(n)MBX(2)] with K[(η(5)-C(5)H(5))MnH(CO)(2)], salt elimination occurs along with a migration of the Mn-bound hydride ligand onto the boron atom, thereby forming dinuclear σ-(halo)boranyl complexes of the form [L(n)M(μ-BHX)Mn(CO)(2)(η(5)-C(5)H(5))]. Most of these complexes react further at room temperature to lose HX and provide metalloborylene complexes [L(n)M-B = Mn(CO)(2)(η(5)-C(5)H(5))] however, when ML(n) = Re(CO)(5) the σ-(halo)boranyl complex decomposes into unidentifiable products. We found through DFT calculations that two electronically and structurally distinct forms of the intermediate σ-(halo)boranyl complexes exist, one of which easily loses HX and one that does not.
Isolierung und Reaktivität eines s‐Block‐Metall‐Antiaromaten
Publisher: Wiley
Date: 21-12-2020
Parallel Manipulation of Bifunctional DNA Molecules on Structured Surfaces Using Kinesin‐Driven Microtubules
Publisher: Wiley
Date: 28-07-2006
Abstract: We have developed a technique to manipulate bifunctional DNA molecules: One end is thiolated to bind to a patterned gold surface and the other end is biotinylated to bind to a microtubule gliding over a kinesin‐coated surface. We found that DNA molecules can be stretched and overstretched between the gold pads and the motile microtubules, and that they can form dynamic networks. This serves as a proof‐of‐principle that biological machineries can be used in vitro to accomplish the parallel formation of structured DNA templates that will have applications in biophysics and nanoelectronics.
σ-Coordination of metal–boryl bonds to gold(i)
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3CC45455J
Abstract: The first ex les of σ-coordinated metal-haloboryl complexes have been synthesised. The haloboryl moiety may be functionalized by nucleophilic substitution reactions, by which more electron-withdrawing substituents may be installed at the boron center.
Neutral zero-valent s-block complexes with strong multiple bonding
Publisher: Springer Science and Business Media LLC
Date: 06-06-2016
DOI: 10.1038/NCHEM.2542
Abstract: The metals of the s block of the periodic table are well known to be exceptional electron donors, and the vast majority of their molecular complexes therefore contain these metals in their fully oxidized form. Low-valent main-group compounds have recently become desirable synthetic targets owing to their interesting reactivities, sometimes on a par with those of transition-metal complexes. In this work, we used stabilizing cyclic (alkyl)(amino)carbene ligands to isolate and characterize the first neutral compounds that contain a zero-valent s-block metal, beryllium. These brightly coloured complexes display very short beryllium-carbon bond lengths and linear beryllium coordination geometries, indicative of strong multiple Be-C bonding. Structural, spectroscopic and theoretical results show that the complexes adopt a closed-shell singlet configuration with a Be(0) metal centre. The surprising stability of the molecule can be ascribed to an unusually strong three-centre two-electron π bond across the C-Be-C unit.
New outcomes of Lewis base addition to diboranes(4): Electronic effects override strong steric disincentives
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6CC01493C
Abstract: Two surprising new outcomes of the reaction of Lewis bases with dihalodiboranes(4) are presented.
Dative Bonding between Group 13 Elements Using a Boron-Centered Lewis Base
Publisher: Wiley
Date: 24-11-2016
Abstract: An electron-rich monovalent boron compound is used as a Lewis base to prepare adducts with Group 13 Lewis acids using both its boron and nitrogen sites. The hard Lewis acid AlCl3 binds through a nitrogen atom of the Lewis base, while softer Lewis acids GaX3 (Cl, Br, I) bind at the boron atom. The latter are the first noncluster Lewis adducts between a boron-centered Lewis base and a main-group Lewis acid.
Controlled homocatenation of boron on a transition metal
Publisher: Springer Science and Business Media LLC
Date: 17-06-2012
DOI: 10.1038/NCHEM.1379
Abstract: Only a handful of elements are able to be controllably homocatenated (that is, to be formed into one- or two-dimensional chains or rings of the element), because most have weak element-element bonds. Boron forms strong B-B bonds, but its favourable cluster formation makes homocatenation very difficult. Recently, the coupling of borylene (:BR) ligands on a metal was predicted computationally. We have brought this prediction to fruition experimentally, and extended it by adding two further borylene units, stepwise forming a B(4) chain bound to a metal under mild conditions. This complex is a useful model for understanding the metal-boron interactions required to promote transition of the boron atoms from borylene ligands to oligoborane networks bound side-on. The concept shows great promise for the controlled construction of one-dimensional boron chains.
Fundamental Differences between Group 8 Metals: Unexpected Oxidation State Preferences and Mechanisms in Ruthenium Borylene Complex Formation
Publisher: Wiley
Date: 09-05-2016
Abstract: The reaction of the salts K[Ru(CO)3 (PMe3 )(SiR3 )] (R=Me, Et) with Br2 BDur or Cl2 BDur (Dur=2,3,5,6-Me4 C6 H) leads to both boryl and borylene complexes of alent ruthenium, the former through simple salt elimination and the latter through subsequent CO loss and 1,2-halide shift. The balance of products can be altered by varying the reaction conditions boryl complexes can be favored by the addition of CO, and borylene complexes by removal of CO under vacuum. All of these products are in competition with the corresponding (aryl)(halo)(trialkylsilyl)borane, a reductive elimination product. The Ru(II) borylene products and the mechanisms that form them are distinctly different from the analogous reactions with iron, which lead to low-valent borylene complexes, highlighting fundamental differences in oxidation state preferences between iron and ruthenium.
Interactions of Isonitriles with Metal-Boron Bonds: Insertions, Coupling, Ring Formation, and Liberation of Monovalent Boron
Publisher: Wiley
Date: 08-07-2016
Abstract: Boryl, borylene, and base-stabilized borylene complexes of manganese and iron undergo a range of different reactions when treated with isonitriles including single, double, and partial isonitrile insertions into metal-boron bonds, ring formation, isonitrile coupling, and the liberation of new monovalent boron species. Two of the resulting cyclic species have also been found to react selectively with anhydrous HCl to form ring-opened products. The erse isonitrile-promoted reactivity of transition-metal-boron compounds has been explored computationally.
Dicyclohexyl(2′,4′,6′-triisopropylbiphenyl-2-yl) phosphine-dichlorophenylborane
Publisher: International Union of Crystallography (IUCr)
Date: 17-10-2009
A base-stabilized iodoborylene complex of platinum(II)
Publisher: Walter de Gruyter GmbH
Date: 06-2013
Abstract: The first base-stabilized iodoborylene platinum complex was prepared through the addition of 4-picoline (4-Pic) to a suspension of an iodo-bridged binuclear iodoboryl complex. An X-ray structure determination of the title compound has characterized the molecular structure as cis-[Pt{BI(4- Pic)}I 2 (PCy 3 )]. The bond lengths lie in the expected range for neutral, base-stabilized borylene complexes. The strong trans influence of the borylene moiety is reflected in the longer Pt-1 distance for the iodo ligand opposite the borylene, compared to that opposite the phosphine ligand
The depolymerizing kinesin MCAK uses lattice diffusion to rapidly target microtubule ends
Publisher: Springer Science and Business Media LLC
Date: 05-2006
DOI: 10.1038/NATURE04736
Abstract: The microtubule cytoskeleton is a dynamic structure in which the lengths of the microtubules are tightly regulated. One regulatory mechanism is the depolymerization of microtubules by motor proteins in the kinesin-13 family. These proteins are crucial for the control of microtubule length in cell ision, neuronal development and interphase microtubule dynamics. The mechanism by which kinesin-13 proteins depolymerize microtubules is poorly understood. A central question is how these proteins target to microtubule ends at rates exceeding those of standard enzyme-substrate kinetics. To address this question we developed a single-molecule microscopy assay for MCAK, the founding member of the kinesin-13 family. Here we show that MCAK moves along the microtubule lattice in a one-dimensional (1D) random walk. MCAK-microtubule interactions were transient: the average MCAK molecule diffused for 0.83 s with a diffusion coefficient of 0.38 microm2 s(-1). Although the catalytic depolymerization by MCAK requires the hydrolysis of ATP, we found that the diffusion did not. The transient transition from three-dimensional diffusion to 1D diffusion corresponds to a "reduction in dimensionality" that has been proposed as the search strategy by which DNA enzymes find specific binding sites. We show that MCAK uses this strategy to target to both microtubule ends more rapidly than direct binding from solution.
Molecular Motors: Single-Molecule Recordings Made Easy
Publisher: Elsevier BV
Date: 03-2002
DOI: 10.1016/S0960-9822(02)00750-9
Abstract: A fusion protein of kinesin and gelsolin binds a short actin filament which can be visualized using a standard fluorescence microscope. This technique has provided new insight into the mechanism of kinesin action, and in principle it can be extended to allow single-molecule assays of any protein.
Isolation and Reactivity of an Antiaromatic s‐Block Metal Compound
Publisher: Wiley
Date: 27-12-2020
Related Organisations
Imperial College London
Location: United Kingdom of Great Britain and Northern Ireland
Related Funding Activities
Discovery Projects - Grant ID: DP210102085
Start Date: 05-2021
End Date: 05-2025
Amount: $450,000.00
Funder: Australian Research Council
View Funded Activity