Atom-Precise Modification of Silver(I) Thiolate Cluster by Shell Ligand Substitution: A New Approach to Generation of Cluster Functionality and Chirality

Abstract

To realize the molecular design of new functional silver(I) clusters, a new synthetic approach has been proposed, by which the weakly coordinating ligands NO in a Ag thiolate cluster precursor can be substituted by carboxylic ligands while keeping its inner core intact. By rational design, novel atom-precise carboxylic or amino acid protected 20-core Ag(I)-thiolate clusters have been demonstrated for the first time. The fluorescence and electrochemical activity of the postmodified Ag clusters can be modulated by alrestatin or ferrocenecarboxylic acid substitution. More strikingly, when chiral amino acids were used as postmodified ligands, CD-activity was observed for the Ag clusters, unveiling an efficient way to obtain atom-precise chiral silver(I) clusters.

Chiral Noble Metal Nanoparticles and Nanostructures

“…In recent years, stable small chiral silver NPs have been synthesized by a combination of different types of ligands such as thiolate/amino acids, thiolate/phosphine, and thiolate/halides . Zang and co‐workers found an effective way to obtain an atomically precise chiral silver cluster; a 20 silver‐atom core thiolate‐protected Ag(I) cluster was sensitized as a precursor containing weakly coordinating ligands (NO 3 − ) and N , N ‐dimethylacetamide (DNAc), to yield a total structure of (CO 3 )@Ag 20 (S t Bu) 10 (NO 3 − ) 8 (DMAc) 4 . This structure is not chiral.…”

“…This structure is not chiral. However, when enantiomeric amino acids (such as alanine, valine, and proline) were used as postmodification ligands together with additional AgNO 3 , new chiral structures were obtained, including: 1) [(CO 3 )@Ag 22 (S t Bu) 10 (alanine) 4 (NO 3 − ) 6 (CH 3 CN) 2 ], 2) (CO 3 )@Ag 23 (S t Bu) 10 (valine) 6 (NO 3 − ) 4 (OH − )(CH 3 CN), and 3) [(CO 3 )@Ag 24 (S t Bu) 10 (proline) 8 (NO 3 − ) 4 (H 2 O)](CH 3 CN) 4 (H 2 O) 3 . X‐ray crystallographic analysis was performed and the structures were determined ( Figure ).…”

“…Right: CD spectra of 1 and 3 in ethanol and 2 in acetonitrile. Adapted with permission . Copyright 2017, American Chemical Society.…”

Synthesis of Atom‐Precise Chiral Ag14 Clusters Protected by Penicillamine Ligands

“…For instance, when the crystal structure of Au 38 cluster was determined by the Jin group, the chirality of the Au 38 cluster is obvious, which stems from the asymmetric arrangement of the ligands on its surface, rather than from the rod‐shaped Au 23 core and achiral ligands . Furthermore, the CD responses have been observed on the atom‐precise Ag 20 clusters postmodified by chiral amino acids ligands, in which the mechanism of chirality may arise from the electronic transitions between the chiral ligands and the achiral Ag 20 S 10 core . As for an example of inherent chiral Au 24 framework reported by Konishi's group, through crystallographic analyses, the chirality was demonstrated to originate from the helically arranged hexagold strands on the gold surface.…”

The Positional Isomeric Effect on the Structural Diversity of Cd(II) Coordination Polymers, Using Flexible Positional Isomeric Ligands Containing Pyridyl, Triazole, and Carboxylate Fragments

“…In this sense, the well-studied luminescent properties [14,15,16,17,18] of d 10 cations, such as Cu(I), Ag(I), and Au(I), as well as their versatility in the construction of complex coordination networks with different types of organic ligands have been the object of interest.…”