Chirality transfer from gold nanocluster to adsorbate evidenced by vibrational circular dichroism

Abstract

The transfer of chirality from one set of molecules to another is fundamental for applications in chiral technology and has likely played a crucial role for establishing homochirality on earth. Here we show that an intrinsically chiral gold cluster can transfer its handedness to an achiral molecule adsorbed on its surface. Solutions of chiral Au38(2-PET)24 (2-PET=2-phenylethylthiolate) cluster enantiomers show strong vibrational circular dichroism (VCD) signals in vibrations of the achiral adsorbate. Density functional theory (DFT) calculations reveal that 2-PET molecules adopt a chiral conformation. Chirality transfer from the cluster to the achiral adsorbate is responsible for the preference of one of the two mirror images. Intermolecular interactions between the adsorbed molecules on the crowded cluster surface seem to play a dominant role for the phenomena. Such chirality transfer from metals to adsorbates likely plays an important role in heterogeneous enantioselective catalysis.

Nonlinear Optical Properties of Thiolate-Protected Gold Clusters: A Theoretical Survey of the First Hyperpolarizabilities

“…The model ligands -SH should lead to higher symmetries in the clusters, since only the symmetry of the Au-S framework and the relative orientation of the ligands with respect to the protecting Au-Soligomers are considered. Certain conformations of actual ligands (such as -SCH 2 CH 2 Ph) may yield the symmetry of the clusters, as demonstrated in recent experimental and theoretical work 65,66. The effect of the ligands itself on the molecular symmetry is best demonstrated by comparing the [Au25 (SCH 2 CH 2 Ph)18 ] -cluster with[Au 25 (capt) …”

Plasmonic Chiral Nanostructures: Chiroptical Effects and Applications

“…[78] The handedness of chiral gold nanocluster can be "transferred" to its adsorbate achiral molecule, and Figure 3c is the schematic of Au 38 (2PET) 24 nanocluster. [79] In this ensemble, the interaction between achiral molecules and chiral gold nanostructure broke the mirror symmetry, resulting in the chirality of molecules.…”

“…Reproduced with permission. [79] Copyright 2015, Nature Publishing Group. d) Schematic of the coupling effect between chiral molecule and plasmonic dimer.…”

Enantioseparation of Au20(PP3)4Cl4 Clusters with Intrinsically Chiral Cores

“…[1] Unlike the extensively studied molecular chirality [2] and that of the microscopic helix, [3] the nanoscale chirality between them remains largely uninvestigated. It is suggested that atomically precise chiral Au nanoclusters [6] would become an ideal platform at the nanoscale for understanding the chiral transfer across the organic-inorganic interface [7] and structure-property relationships. It is suggested that atomically precise chiral Au nanoclusters [6] would become an ideal platform at the nanoscale for understanding the chiral transfer across the organic-inorganic interface [7] and structure-property relationships.…”

“…[4] Although significant advances have been achieved in this field, [5] the chiral evolution from molecules to nanostructures, as well as the corresponding influence on their properties are not clearly elucidated yet. It is suggested that atomically precise chiral Au nanoclusters [6] would become an ideal platform at the nanoscale for understanding the chiral transfer across the organic-inorganic interface [7] and structure-property relationships. [8] Among chiral Au nanoclusters,A u 20 is of special interest owing to its intrinsic chiral core,w hich is quite distinct from other clusters in which the chirality has other origins.Indetail, the atomic structure of Au 20 core is ac entered icosahedral Au 13 unit surrounded by ahelical arrangement of Au 7 fan-like motif ( Figure S1 in the Supporting Information).…”