Cu Cluster with Partial Cu(0) Character: Difference in Electronic Structure from Isostructural Silver Analog.

An atom-precise Cu-containing copper cluster, Cu(CBHS)(CHCN) (abbreviated as Cu-8CHCN) is reported, which is synthesized via a simultaneous reduction strategy and fully characterized by single-crystal X-ray diffraction, ESI-TOF-MS, and X-ray photoelectron spectroscopy. Cu-8CHCN is the only copper cluster that has a virtually identical silver structural analog, i.e., Ag(CBHS)(CHCN) (hereafter as Ag-8CHCN). Nevertheless, density functional theory calculations reveal that the electronic structure of Cu-8CHCN differs significantly from the superatom electronic configuration of Ag-8CHCN. Moreover, Cu-8CHCN shows room-temperature luminescence and good electrocatalytic activities in the ethanol oxidation reaction and detection of HO. This pair of unprecedented analogous molecular nanoscale systems offer an ideal platform to investigate the fundamental differences between copper and silver in terms of catalytic activity and optical properties.