Gold tetrahedra coil up: Kekulé-like and double helical superstructures

Abstract

Structures of gold clusters resemble the benzene and DNA molecules and reveal a “supermolecule” origin of the magic-sized clusters.

Correlating the Structure and Optical Absorption Properties of Au76(SR)44 Cluster

“…We therefore further compared the Au core structures of Au n (SR) m clusters (n ≤ 52) with bulk Au crystal. As shown in Scheme 2a, the experimentally resolved or theoretically predicted Au cores in Au n (SR) m clusters (n ≤ 52) are indeed identical to a small group of Au atoms in bulk crystal with the exception of Au 25 (SR) 18 − and Au 38 (SR) 24 . Au 25 (SR) 18 − and Au 38 (SR) 24 are made of an icosahedra Au 13 or bi-icosahedra Au 23 core, where the Au core atoms do not adopt a fcc-like packing.…”

“…Recently, significant experimental advances have been made in the structure determination of several magic-sized Au n (SR) m clusters in the size region of about 0.5−2 nm. The atomic structures of Au 133 (SPh-t-Bu) 52 , 12,13 Au 130 (SC 12 H 25 ) 50 , 14,15 Au 102 (p-MBA) 44 , 16 Au 68 (3-MBA) 31−34 (3-MBA = 3-mercaptobenzoic acid), 17 Au 52 (TBBT) 32 (TBBT = 4-tert-butylbenzenethiol), 10 Au 40 (o-MBT) 24 (o-MBT = mercaptobenzothiazole), 18 Au 38 (SCH 2 CH 2 Ph) 24 , 19 Au 25 (SCH 2 CH 2 Ph) 18 − , 20,21 Au 36 (SPht-Bu) 2 4 , 2 2 Au 3 0 S(S-t-Bu) 1 8 , 2 3 Au 2 8 (SPh-t-Bu) 2 0 , 2 4 Au 24 (SCH 2 Ph-t-Bu) 20 , 25 Au 24 (SAdm) 16 , 26 Au 23 (SPh) 16 − , 27 Au 20 (SPh-t-Bu) 16 , 28 and Au 18 (SC 6 H 11 ) 14 29, 30 were determined by single X-ray crystallography and powerful single-particle transmission electron microscopy (SP-TEM). Based on the resolved cluster structures, a generic structural rule denoted as the "divide-and-protect" concept has been summarized.…”

“…According to this concept, 31,32 any Au n (SR) m nanoclusters can be divided into a symmetric gold core covered by interfacial staple motifs (i.e., −SR[AuSR] x −, x = 1, 2, 3, ...). Over the past few years, the "divide-and-protect" concept combined with density functional theory (DFT) computations has led to predictions of a number of cluster structures, including Au 187 (SR) 68 , 33 Au 144 (SR) 60 , 34 Au 68 (SR) 34 , 35 Au 67 (SR) 35 2− , 36 Au 44 (SR) 28 , 37 Au 40 (SR) 24 , 38 Au 38 (SR) 24 , 39,40 Au 25 (SR) 18 − , 41 Au 24 (SR) 20 , 42 Au 20 (SR) 16 , 43 Au 18 (SR) 14 , 44 Au 15 (SR) 13 , 45,46 and Au 12 (SR) 9 + . 47 Although tremendous research efforts have been made on the characterization of atomic structures, an important issue about the structural evolution of Au n (SR) m clusters in the size range 1−2 nm remained elusive.…”

“…9 The SP-TEM and DFT calculations indicated the atomic positions of Au atoms in the Au 68 (SR) 32 cluster adopted a face-centered-cubic (fcc)-like spherical framework. 17,54 The reported atomic structures of Au 67 (SR) 35 2− , Au 68 (SR) 32 , and Au 68 (SR) 34 suggested a popular structural evolution pathway for the thiolate-protected gold nanocluster; i.e., Au 25 (SR) 18 − , Au 67 (SR) 35 2− , Au 68 (SR) 32 , Au 68 (SR) 34 , Au 130 (SR) 50 , Au 133 (SR) 52 , and Au 144 (SR) 60 created a succession of spherical structures which show a core−shell structural pattern. This kind of evolution fashion is consistent with the predictions made by Teo et al from the summarization of crystal structures of ligand protected group 11 metal clusters.…”

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

“…The majority of chiral metal nanoclusters known to date are of types (a) [27][28][29][30][31][32][33][34][35][36] and (b) 16,17,[37][38][39] , with a few belonging to types (c) and (d). [40][41][42] As prepared, many of these chiral metal nanoclusters (types b-d) are racemic mixtures that require separation and purification by various optical resolution methods. Enantioseparation of Au nanoclusters (e.g., Au28, Au38, Au40) has been reported by using chiral HPLC columns.…”