Structurally Precise Dichalcogenolate-Protected Copper and Silver Superatomic Nanoclusters and Their Alloys

Abstract

CONSPECTUS:The chalcogenolato silver and copper superatoms are currently a topic of cutting edge research besides the extensively studied Au n (SR) m clusters. The crystal structural analysis is an indispensable tool to gain deep insights into the anatomy of these subnanometer clusters. The metal framework and spatial arrangement of the chalcogenolates around the metal core assist in unravelling the structure-property relationship and fundamental mechanistic involved in their fabrication. In this Account, we discuss our contribution towards the development of dichalcogenolato Ag and Cu cluster chemistry covering their fabrications and precise molecular structures. Briefly introducing the significance of the single crystal structures of the atomically precise clusters; the novel dichalcogenolated 2-electron superatomic copper and their alloy systems are presented first. The [Cu 13 {S 2 CNR} 6 {C≡CR'} 4 ] + is so far the first unique copper cluster having Cu 13 centred cuboctahedron, which is a miniature of bulk fcc. The galvanic exchange of the central Cu with Ag/Au results in a similar anatomy of formed bimetallic [Au/Ag@Cu 12 (S 2 CN n Bu 2 ) 6 (C≡CPh) 4 ][CuCl 2 ] species. This is unique in a sense that other contemporary M 13 cores in group 11 superatomic chemistry are compact icosahedra. The central doping of Ag or Au significantly affects the physiochemical properties of the bimetallic Cu rich clusters. It is manifested in the dramatic quantum 1 yield enhancement of the doped species [Au@Cu 12 (S 2 CN n Bu 2 ) 6 (C≡CPh) 4 ] + with a value of 0.59 at 77 K in 2-MeTHF. In the second part, the novel eight-electron dithiophosphate-and diselenophosphate-protected silver systems are presented. A completely different type of architecture was revealed for the first time from the successful structural determination of [Ag 21 {S 2 P(O i Pr) 2 } 12 ] + , [Ag 20 {S 2 P(O i Pr) 2 } 12 ] and [Au@Ag 19 {S 2 P(OPr) 2 } 12 ]. They exhibit a non-hollow M 13 (Ag or AuAg 12 ) icosahedron, capped by 8 and 7 Ag atoms in the former and latter two species, respectively. The overall metal core units are protected by 12 dithiophosphate ligands and the metal-ligand interface structure was found to be quite different from that of Au n (SR) m . Notably, the [Ag 20 {S 2 P(O i Pr)} 12 ] cluster provides the first structural evidence of silver superatom with a chiral metallic core. This chirality arises through the simple removal of one of capping Ag + cation of [Ag 21 {S 2 P(O i Pr) 2 } 12 ] + present on its C 3 axis. Further, the effects of the ligand exchange on the structures of [Ag 20 {Se 2 P(O i Pr) 2 } 12 ], [Ag 21 {Se 2 P(OEt) 2 } 12 ] + and [AuAg 20 {Se 2 P(OEt) 2 } 12 ] + are studied extensively. The structure of the former species is similar to its dithiophosphate counterpart (C 3 symmetry). The latter two (T symmetry) differ in the arrangement of 8 capping Ag atoms, as they form a cube engraving the Ag 13 (AuAg 12 ) icosahedron. The blue shifts in absorption spectra and photoluminescence further indicate the strong influence of ...

Insight into the Geometric and Electronic Structures of Gold/Silver Superatomic Clusters Based on Icosahedron M13 Units and Their Alloys

“…Furthermore, DFT calculations indicate that [Ag 13 ] 5+ can be treated as an 8 e − superatomic unit (with 1S 2 1P 6 closed‐shell configuration) capped by a external shell (Figure B, right) . Many dichalcogenolated silver superatomic nanoclusters based on [Ag 21 {S 2 P(O i Pr) 2 } 12 ] + , through ligand and doping engineering, such as [Ag 21 {Se 2 P(OEt) 2 } 12 ] + , [Ag 20 {S 2 P i (OR) 2 } 12 , [Au@Ag 19 {S 2 P(OPr) 2 } 12 ], [Ag 20 {Se 2 P(O i Pr) 2 } 12 ], [AuAg 20 {Se 2 P(OR) 2 } 12 ] + , and [Au 3 Ag 18 {Se 2 P(O i Pr) 2 } 12 ] + , were obtained and summarized in detail by the group of Liu in a review on copper/silver superatomic nanoclusters . With more in‐depth research, the exploration of gold and silver nanocluster analogues has attracted attention to understand fundamental differences .…”

Unified reciprocity of dithiophosphate by dichalcogenophosph(in)ate ligands on copper hydride nanoclusters via ligand exchange reaction

“…Additionally, two new copper hydrides 3 and 4 were isolated and the synthesis of cluster 4 from 3 via ligand exchange method is a remarkable instance where structural anatomy was retained at utmost precision. Our synthesis of copper hydrides via ligand exchange is parallel to the synthesis of Se‐protected silver nanoparticles . This methodology is particularly useful for the supporting ligands such as Se‐donor ligands that are not stable in solution in the presence of reducing reagents.…”

“…In this context, atomically precise gold clusters have been utilized often as promising templates for fabrication. [12] For example, the ligand exchange reactions on [Au 38 24 ] and [Au 40 24 ] (2-PET = 2-phenylethanethiolate) clusters with BINAS (BINAS=1,1 0 -binapthyl-2,2 0 -dithiol) as an incoming ligand were reported by Knoppe and coworkers. [11a] Ackerson et al reported the first single-crystal X-ray structure of a partially exchanged NC [Au 102 (p-MBA) 40 (p-BBT) 4 ] [11b] by the ligand replacement of p-MBA (para-mercaptobenzoic acid) with p-BBT (para-bromobenzene thiol) on a 5 min timescale of exchange reaction.…”

“…Xie and coworkers performed ligand exchange on [Au 25 (SR) 18 ] to explore how the ligands affect the electronic structure of the metal core. [11c] The transformation of achiral nanocluster [Au 36 (tbbt) 24 ] from intrinsically chiral [Au 38 (pet) 24 ] by the replacement of thiol-ligand with 4-tertbutylbenzenethio (tbbt) was reported in Zeng et al of late. [11d] The majority of NCs synthesized via ligand exchange methods are thiolate-protected clusters.…”

Structurally Precise Silver Sulfide Nanoclusters Protected by Rhodium(III) Octahedra with Aminothiolates

“…[30] This structural feature appears to prevent the shrinkage of the clusters,which is caused by the replacement of Ag I by Cu I in the outer and inner shells due to the formation of the much shorter Cu À Sb onds compared with the Ag À Sb onds.T he replacement of all the Ag I atoms in the [Ag 4 S] 2+ core also induces the shrinkage of the clusters.T hus,t he three Ag I atoms that form shorter AgÀSb onds because of the 2coordination geometry in the [Ag 4 S] 2+ core,r ather than the remaining Ag I atom with 4-coordination geometry,u ndergo replacement by Cu I atoms in 1.T his is the first nanocluster system that shows aA g I -to-Cu I exchange at the core of the cluster structure,a lthough Liu and co-workers previously reported the insertion of Au I atoms into the center of "colloidal" silver or copper nanoclusters. [43,44] …”