Replacement of secondary ligands enhance the luminescence 30-fold in Ag29 cluster.

Two ligand‐protected nanoscale silver moieties, [Ag46(SPhMe2)24(PPh3)8](NO3)2 and [Ag40(SPhMe2)24(PPh3)8](NO3)2 (abbreviated as Ag46 and Ag40, respectively) with almost the same shell but different cores were synthesized simultaneously. As their external structures are identical, the clusters were not distinguishable and become co‐crystallized. The occupancy of each cluster was 50 %. The outer shell of both is composed of Ag32S24P8, which is reminiscent of fullerenes, and it encapsulates a well‐studied core, Ag14 and a completely new core, Ag8, which correspond to a face‐centered cube and a simple cube, respectively, resulting in the Ag46 and Ag40 clusters. The presence of two entities (Ag40 and Ag46 clusters) in a single crystal and their molecular formulae were confirmed by detailed electrospray ionization mass spectrometry. The optical spectrum of the mixture showed unique features which were in good agreement with the results from time‐dependent density functional theory (TD‐DFT).

We present the first example of polymorphism (cubic & trigonal) in single crystals of an atomically precise monolayer protected cluster, Ag29(BDT)12(TPP)43-. We demonstrate that C-Hπ interactions of the secondary ligands (TPP) are dominant in a cubic lattice compared to a trigonal lattice, resulting in a greater rigidity of the structure, which in turn, results in a higher luminescence efficiency in it.

We introduce a cluster coprotected by thiol and diphosphine ligands, [Ag22(dppe)4(2,5-DMBT)12Cl4]2+ (dppe = 1,2-bis­(diphenylphosphino)­ethane; 2,5-DMBT= 2,5-dimethylbenzenethiol), which has an Ag10 core encapsulated by an Ag12(dppe)4(2,5-DMBT)12Cl4 shell. The Ag10 core comprises two Ag5 distorted trigonal bipyramidal units and is uncommon in Au and Ag nanoclusters. The electrospray ionization mass spectrum reveals that the cluster is divalent and contains four free electrons. An uncommon crystallization-induced enhancement of emission is observed in the cluster. The emission is weak in the solution and amorphous states. However, it is enhanced 12 times in the crystalline state compared to the amorphous state. A detailed investigation of the crystal structure suggests that well-arranged C–H···π and π···π interactions between the ligands are the major factors for this enhanced emission. Further, in-depth structural elucidation and density functional theory calculations suggest that the cluster is a superatom with four magic electrons.

Herein, we present an intercluster reaction leading to new trimetallic nanoclusters (NCs) using bimetallic and monometallic NCs as reactants. Dithiol protected bimetallic MAg 28 (BDT) 12 (PPh 3 ) 4 (BDT = 1,3-benzenedithiol and M = Ni, Pd, or Pt) and monothiol protected Au 25 (PET) 18 (PET = 2-phenylethanethiol) were used as model NCs. A mixture of trimetallic MAu x Ag 28−x (BDT) 12 (PPh 3 ) 4 (x = 1− 12) and bimetallic Ag x Au 25−x (PET) 18 (x = 1−7) NCs were formed during the reaction as understood from timedependent electrospray ionization mass spectrometry (ESI MS). Detailed studies of intercluster reaction between Ag 29 (BDT) 12 (PPh 3 ) 4 and Au 25 (PET) 18 were also performed. Although both MAg 28 (BDT) 12 (PPh 3 ) 4 (M = Ag, Ni, Pd, or Pt) and Au 25 (PET) 18 contain 13 atoms icosahedral core, only a maximum of 12 Au doped NCs were formed for the former as a major product and not the 13 Au doped one, unlike the previous reports of intercluster reaction. The transfer of Ni, Pd, or Pt atom from the center of icosahedron of MAg 28 (BDT) 12 (PPh 3 ) 4 to Au 25 (PET) 18 was not observed, which suggests that the central atom is not involved in the reaction. Density functional theory (DFT) calculations were performed to know structures and properties of the formed NCs. This study demonstrates the use of intercluster reaction as an effective synthetic protocol to make multimetallic alloy NCs.