First enantioseparation and circular dichroism spectra of Au38 clusters protected by achiral ligands

Dolamic, Igor; Knoppe, Stefan; Dass, Amala; Bürgi, Thomas

doi:10.1038/ncomms1802

Cited by 458 publications

(557 citation statements)

References 44 publications

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“…Gold(III) chloride trihydrate (≥ 99,9 %), butanethiol (99 %), hexanethiol (99 %), phenylethanethiol (≥ 99 %), sodium borohydride (95 %), tetraoctylammonium bromide (TOABr, 98 %) and trans-2-[3-(4-tertbutylphenyl)-2-methyl-2-propenylidene]malononitrile (DCTB, > 98 %) were purchased from Sigma-Aldrich. Tetrathiolated calix [4]arene (25,26,27,28-tetrakis(4-mercapton-butoxy)calix [4]arene) was synthesized according to a reported method. 32 All the chemicals were used as received without further purification.…”

Section: Methodsmentioning

confidence: 99%

Simple and Efficient Separation of Atomically Precise Noble Metal Clusters

Ghosh

Hassinen²,

Pulkkinen

et al. 2014

Anal. Chem.

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ABSTRACT:There is an urgent need for accessible purification and separation strategies of atomically precise metal clusters in order to promote the study their fundamental properties. Although the separation of mixtures of atomically precise gold clusters Au25L18, where L are thiolates, has been demonstrated by advanced separation techniques, we present here the first separation of metal clusters by thin layer chromatography (TLC), which is simple yet surprisingly efficient. This method was successfully applied to a binary mixture of Au25L18 with different ligands, as well as to a binary mixture of different cluster cores, Au25 and Au144, protected with the same ligand. Importantly, TLC even enabled the challenging separation of a multi-component mixture of mixedmonolayer-protected Au25 clusters with closely similar chemical ligand compositions. We anticipate that the realization of such simple yet efficient separation technique will progress the detailed investigation of cluster properties.

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Section: Methodsmentioning

confidence: 99%

Simple and Efficient Separation of Atomically Precise Noble Metal Clusters

Ghosh

Hassinen²,

Pulkkinen

et al. 2014

Anal. Chem.

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“…4,30,31 The 'chiral footprint model' is also implicated in the origin of optical activity in metalbased electronic transitions. 7,32 Our work shows the importance of considering the dynamical response of the molecular adsorption footprint to the local adsorption environment, leading to more nuanced behaviour than hitherto anticipated, which could, ultimately, be tailored to create environment and stimuliresponsive chiral surfaces.…”

Section: Introductionmentioning

confidence: 91%

“…The nanoscale control of chiral molecular assembly at surfaces is of central importance in fields as diverse as chiral separations, 1,2 heterogeneous enantioselective catalysis, 3,4 plasmonics, 5 chiroptical switching 6,7 and biosensors. 8 In all cases, the surface function is profoundly influenced by how individual enantiomers organize at the local and the global level, therefore the outstanding problem in the field is to understand the factors that drive enantiomer assembly and segregation.…”

Section: Introductionmentioning

confidence: 99%

Chiral segregation driven by a dynamical response of the adsorption footprint to the local adsorption environment: bitartrate on Cu(110)

Darling

Forster

Lin

et al. 2017

Phys. Chem. Chem. Phys.

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Local or global ordering of chiral molecules at a surface is a key step in both chiral separation and heterogeneous enantioselective catalysis. Using density functional theory and scanning probe microscopy results, we find that the accepted structural model for the well known bitartrate on Cu(110) chiral system cannot account for the chiral segregation observed. Instead, we show that this strongly bound, chiral adsorbate changes its adsorption footprint in response to the local environment. The flexible adsorption geometry allows bitartrate to form stable homochiral trimer chains in which the central molecule restructures from a rectangular to an oblique footprint, breaking its internal hydrogen bonds in order to form strong intermolecular hydrogen bonds to neighbouring adsorbates. Racemic structures containing mixed enantiomers do not form strong hydrogen bonds, providing the thermodynamic driving force for the chiral separation that is observed experimentally. This result shows the importance of considering the dynamical response of molecular adsorption footprints at the surface in directing chiral assembly and segregation. The ability of strongly-chemisorbed enantiomers to change footprint depending on the local adsorption environment indicates that supramolecular assemblies at surfaces may exhibit more complex dynamical behaviour than hitherto suspected, which, ultimately, could be tailored to lead to environment and stimuli-responsive chiral surfaces.

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“…Enantioseparation of Au nanoclusters (e.g., Au28, Au38, Au40) has been reported by using chiral HPLC columns. [43][44][45] For example, Knoppe et al separated Au102…”

mentioning

confidence: 99%

Asymmetric Synthesis of Chiral Bimetallic [Ag₂₈Cu₁₂(SR)₂₄]^4– Nanoclusters via Ion Pairing

et al. 2016

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In this work, a facile ion-pairing strategy for asymmetric synthesis of optically active negatively charged chiral metal nanoparticles using chiral ammonium cations is demonstrated. A new thiolated chiral three-concentricshell cluster, [Ag 28 Cu 12 (SR) 24 ] 4− , was first synthesized as a racemic mixture and characterized by single-crystal X-ray structure determination. Mass spectrometric measurements revealed relatively strong ion-pairing interactions between the anionic nanocluster and ammonium cations. Inspired by this observation, the as-prepared racemic mixture was separated into enantiomers by employing chiral quaternary ammonium salts as chiral resolution agents. Subsequently, direct asymmetric synthesis of optically active enantiomers of [Ag 28 Cu 12 (SR) 24 ] 4− was achieved by using appropriate chiral ammonium cations (such as N-benzylcinchoninium vs N-benzylcinchonidinium) in the cluster synthesis. These simple strategies, ionpairing enantioseparation and direct asymmetric synthesis using chiral counterions, may be of general use in preparing chiral metal nanoparticles.

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First enantioseparation and circular dichroism spectra of Au38 clusters protected by achiral ligands

Cited by 458 publications

References 44 publications

Simple and Efficient Separation of Atomically Precise Noble Metal Clusters

Simple and Efficient Separation of Atomically Precise Noble Metal Clusters

Chiral segregation driven by a dynamical response of the adsorption footprint to the local adsorption environment: bitartrate on Cu(110)

Asymmetric Synthesis of Chiral Bimetallic [Ag₂₈Cu₁₂(SR)₂₄]^4– Nanoclusters via Ion Pairing

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First enantioseparation and circular dichroism spectra of Au38 clusters protected by achiral ligands

Cited by 458 publications

References 44 publications

Simple and Efficient Separation of Atomically Precise Noble Metal Clusters

Simple and Efficient Separation of Atomically Precise Noble Metal Clusters

Chiral segregation driven by a dynamical response of the adsorption footprint to the local adsorption environment: bitartrate on Cu(110)

Asymmetric Synthesis of Chiral Bimetallic [Ag28Cu12(SR)24]4– Nanoclusters via Ion Pairing

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Product

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Asymmetric Synthesis of Chiral Bimetallic [Ag₂₈Cu₁₂(SR)₂₄]^4– Nanoclusters via Ion Pairing