The positional isomerism in bimetal nanoclusters†
Enriching the variety of isomerism in the nanocluster field is exciting but challenging. In this work, for the first time we graft the concept of positional isomerism in organic molecules onto thiolate-stabilized nanoclusters and report such positional isomerism. The structure of the novel nanocluster Au12Ag32(2-EBT)26(PPh3)4 (2-EBTH = 2-ethylbenzenethiol) was characterized by single crystal X-ray crystallography. The result indicated that the prepared nanocluster Au12Ag32(2-EBT)26(PPh3)4 has the same Ag/Au molar ratio as the existing Au12Ag32(3,4-DFT)30 (3,4-DFTH = 3,4-difluorothiophenol) nanocluster but with an entirely different surface structure. Interestingly, another fascinating structural feature in Au12Ag32(2-EBT)26(PPh3)4 is the presence of chirality, which is a particular distinguishing structural characteristic among the reported bimetal nanoclusters to the best of our knowledge.