Isomer Structural Transformation in Au–Cu Alloy Nanoclusters: Water Ripple‐Like Transfer of Thiol Ligands

Abstract

Structure isomerism is observed in noble metal nanoclusters; however, the mechanism study of this process is rarely reported. Herein, by using the biphosphine ligands instead of phosphine ligands, the high symmetry of the Au2Cu6(PPh3)2(SAdm)6 nanocluster is successfully broken and [Au4Cu4(L1)2(SAdm)5]Br (where, L1 is bis(diphenylphosphine)methane, DPPM) nanocluster is obtained with chiral arrangement. This newly obtained nanocluster contains a total of four isomers in crystal unit cell. Interestingly, these isomers undergo rapid isomorphism in solution, which is confirmed by 1H‐1H COSY spectrum. Density functional theory calculations demonstrate that the water ripple–like transfer of the thiol ligands results from the isomorphism of nanoclusters.

Reversible Cu–S Motif Transformation and Au4 Distortion via Thiol Ligand Exchange Engineering

“…Therefore, the asymmetric distribution of ligands on the cluster surface is responsible for the chirality of Au 4 Cu 4 (Figure 4A). 36 However, for Au 4 Cu 5 , only two isomers labeled a and b can be observed in the packing model (Figure 4B). Au 4 Cu 5 could be also viewed as a two-gold metal kernel protected by phosphine ligands, further surrounded by a Au 2 Cu 5 S 6 P 2 motif structure as a helix.…”

“…It is noteworthy that isomers a and a′ differ only in the position of one thiol ligand, where one is above and the other is below (highlight in the space fill model in Figure C). Therefore, the asymmetric distribution of ligands on the cluster surface is responsible for the chirality of Au 4 Cu 4 (Figure A) . However, for Au 4 Cu 5 , only two isomers labeled a and b can be observed in the packing model (Figure B).…”

“…Herein, we report a “maintenance and reconstruction” strategy to render a controllable conversion of surface S–M–S motifs. Upon reaction with cyclohexyl mercaptan (C 6 H 12 S), [Au 4 Cu 4 (SAdm) 5 (Dppm) 2 ]Br (abbreviated to Au 4 Cu 4 ) was converted to [Au 4 Cu 5 (C 6 H 11 S) 6 (Dppm) 2 ]­(BPh 4 ) (abbreviated to Au 4 Cu 5 ) accompanied by the Cu 4 (SAdm) 5 motif transformed to Cu 5 (C 6 H 11 S) 6 , which was determined by single-crystal X-ray diffraction (SC-XRD) (Scheme ). The formula of these two nanoclusters was further confirmed by electrospray ionization mass spectrometry (ESI-MS), thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS).…”

Multiple Ways Realizing Charge‐State Transform in AuCu Bimetallic Nanoclusters with Atomic Precision

“…In the past decades, AuCu bimetallic NCs have shown excellent photoluminescence, [ 44,45 ] chirality, [ 46,47 ] and catalytic activities. [ 48 ] Our group recently proposed that reaction of Cu II (SR) 2 and [Au 25 (PET) 18 ] − may lead to the formation of the unstable 7‐electron [Cu 1 Au 24 (PET) 18 ] 0 species, which show a different charge state with the [Cu x Au 25− x (PET) 18 ] − ( x = 0–2) by introducing NaBH 4 in the reaction of Cu II (SR) 2 and [Au 25 (SR) 18 ] − , demonstrating the variability of the charge states of the AuCu NCs.…”

Structure and Properties of Au5Cu6(Dppf)2(SAdm)6)(BPh4)

“…Therefore, there are various strategies for controlling the structures of Au–Cu alloy clusters. Recently, the [Au 4 Cu 4 (SAdm) 5 (Dppm) 2 ] + with a quadrilateral Cu 4 ring could be converted into [Au 4 Cu 5 (CHT) 6 (Dppm) 2 ] + with Cu 5 ring via ligand engineering . Inspired by these two nanoclusters and early reported Au 2 Cu 6 (SAdm) 6 (PPh 2 Py) 2 , we look forward to regulating the synthesis strategy to obtain new gold–copper clusters with similar structures and sizes, which would facilitate comprehension of structure-performance relationships.…”