Self-Assembly of Silver Clusters into One- and Two-Dimensional Structures and Highly Selective Methanol Sensing

The development of new materials for the design of sensitive and responsive sensors has become a crucial research direction. Here, two silver cluster-based polymers (Ag-CBPs), including one-dimensional {[Ag22(L1)8(CF3CO2)14](CH3OH)2}n chain and two-dimensional {[Ag12(L2)2(CO2CF3)14(H2O)4(AgCO2CF3)4](HNEt3)2}n film, are designed and used to simulate the human nose, an elegant sensor to smells, to distinguish organic solvents. We study the relationship between the atomic structures of Ag-CBPs determined by x-ray diffraction and the electrical properties in the presence of organic solvents (e.g., methanol and ethanol). The ligands, cations, and the ligated solvent molecules not only play an important role in the self-assembly process of Ag-CBP materials but also determine their physiochemical properties such as the sensing functionality

A Homoleptic Alkynyl‐Ligated [Au13Ag16L24]3‐ Cluster as a Catalytically Active Eight‐Electron Superatom

A brand new alkynylated cluster [Au 13 Ag 16 (C 10 H 6 NO) 24 ] 3- is prepared by NaBH 4 mediated reduction method. The AuAg clusters are confirmed by various sophisticated characterization techniques. It manifested the unique metal framework of “Au center @Ag 12 @Au 12 Ag 4 ” is protected by 24 atypical alkyne ligands L (L = C 10 H 6 NO). The ligands were found to construct a unique type of motif L-(Ag)-Au-(Ag)-L at the cluster interface, where, the alkyne (C≡C) group of each L was linked by sharing an Au atom through the σ bonds and each C≡C group was discretely connected to chemically different Ag atom (Ag icosahedral /Ag cap ) through π bonds. The electronic and optical properties of [Au 13 Ag 16 L 24 ] 3- were studied in detail. DFT characterized the cluster as a clear 8-electron superatom, and peaks in the optical absorption spectrum were successfully interpreted in terms of the P and D superatom states. The supported Au 13 Ag 16 L 24 /CeO 2 catalyst exhibited high catalytic activity and selectivity towards the A 3 -coupling reaction involving benzaldehyde, diethylamine and phenylacetylene.peerReviewe

Improvements in the Ligand-Exchange Reactivity of Phenylethanethiolate-Protected Au₂₅ Nanocluster by Ag or Cu Incorporation

This study reports improvements in the ligand-exchange reactivity of phenylethanethiolate-protected Au₂₅ cluster (Au₂₅(SC₂H₄Ph)₁₈) following Ag or Cu incorporation. Following the synthesis of Au_{25–<i>x</i>}M_<i>x</i>(SC₂H₄Ph)₁₈ (M = Au, Ag, Cu, or Pd), we determined the ligand-exchange reaction rates, using octanethiol (C₈H₁₇SH) as the exchange ligand, by employing mass spectrometry. The results show that incorporating Ag and Cu enhances the ligand-exchange reactivity of the clusters. On the basis of density functional theory calculations, it is concluded that the elevated reactivity of Au_{25–<i>x</i>}M_<i>x</i>(SC₂H₄Ph)₁₈ (M = Ag or Cu) results from the more highly positive charge density of metal atoms in the staple upon Ag or Cu substitution. In addition, in the presence of Au_{25–<i>x</i>}M_<i>x</i>(SC₂H₄Ph)₁₈ (M = Ag or Cu; <i>x</i> ≠ 0), an improvement in the ligand-exchange reaction rate was also observed for Au₂₅(SC₂H₄Ph)₁₈, even though this cluster does not include a heteroatom. This unexpected behavior is attributed to the contribution of a chemical reaction between clusters. These findings are expected to deepen our understanding of ligand-exchange reactions, and lead to design guidelines for the creation of Au_<i>n</i>(SR)_<i>m</i> clusters exhibiting new chemical compositions and functions, using this reaction