Superatomic Three-Center Bond in a Tri-Icosahedral Au₃₆Ag₂(SR)₁₈ Cluster: Analogue of 3c-2e Bond in Molecules

Abstract

Probing the nature of electronic stability for ligand-protected gold clusters is important in gold chemistry. A thermally stable Au36Ag2(SR)18 nanocluster was synthesized recently. It has a D 3h tri-icosahedral [Au30Ag2]12+ core with 20 valence electrons, which does not follow the magic number of gold superatoms. Herein, we propose a superatomic three-center bond to unveil its electronic stability. The [Au30Ag2]12+ core is viewed as a union of three face-fused superatoms, and chemical bonding analysis suggests a three-superatom-center two-electron (3sc-2e) bond for the octet rule of each superatom, which mimics the bonding framework of the D 3h O3 2– molecule. Moreover, a liganded tri-icosahedral [Au27Pt3Ag2]11+ core with 18 valence electrons is predicted, and three 2sc-2e bonds are formed between each of two superatoms to satisfy the octet rule (analogue of D 3h O3), indicating the flexibility of superatomic bonding. Such a superatomic three-center bond extends the community of superatomic bonding and gives a new perspective for superatom assembling.

Second-order superatoms: Au52-PAP featuring a three-dimensional cluster-of-clusters core

“…S1,† the deviations from ideal icosahedrons are denoted. Such deviations are in line with those obtained for the Au 13 linearly-fused cores in Au 26 , 64,65 Au 25 Cl 2 , 37 and Au 38 clusters 53,66–68 and cyclic arrays, 33,36,69,70 enabling bonding combinations in 1D, 2D, and 3D aggregates.…”

Unraveling the flexible aromaticity of C13H9+/0/−: a 2D superatomic-molecule theory

“…A similar 3sc-2e bond was recently uncovered in a tri-icosahedral Au 36 Ag 2 (SR) 18 cluster as well, by using superatomic valence bond theory, accounting for its electronic and thermal stability. 31 In comparison with C 13 H 9 that distinguishes its aand b-p electrons is not presented here, but the following chemical bonding analyses will provide chemically intuitive pictures.…”

“…A similar 3sc–2e bond was recently uncovered in a tri-icosahedral Au 36 Ag 2 (SR) 18 cluster as well, by using superatomic valence bond theory, accounting for its electronic and thermal stability. 31 In comparison with C 13 H 9 +/− where all electrons appear in pairs, C 13 H 9 ˙ with an unpaired electron will necessarily display different electronic structures between its α- and β-π electrons. Considering that the orbital current of C 13 H 9 ˙ was previously reported as an average of C 13 H 9 + and C 13 H 9 − currents, 17 and the NICS(1) contour plane of C 13 H 9 ˙ shows a transition form with similar characteristics to those of both C 13 H 9 + and C 13 H 9 − , the α- and β-π electrons are conceived to follow the bonding patterns of C 13 H 9 − and C 13 H 9 + , respectively.…”

“…Superatoms have been widely studied, and are capable of forming superatomic bonds in various systems. [26][27][28][29][30][31][32] Very recently, we proposed a two-dimensional (2D) superatomic-molecule theory where benzenoid units in p-conjugated systems could be rationally taken as 2D superatoms to simplify the investigations of relevant electronic and bonding information. 33 Benzene featuring electronic closedshell and 6 p electrons is viewed as a 2D analogue of Ne and thus symbolized as } Ne.…”

Shape control with atomic precision: anisotropic nanoclusters of noble metals

“…245 Moreover, the new series of NCs was used in a comparative study in hydrogen evolution reaction (HER). 245 The tri-I h NC exhibited high catalytic activity for HER due to its low ligand-to-metal ratio, low-coordinated Au atoms and unfilled superatomic orbitals, providing a new strategy for constructing highly active catalysts from HER-inert metals ( e.g. Au) via atomically precise nanochemistry.…”