Infrared photodissociation spectroscopy of mass selected homoleptic copper carbonyl cluster cations in the gas phase

摘要

Infrared spectra of mass-selected homoleptic copper carbonyl cluster cations including dinuclear Cu_2(CO)_6~+ and Cu_2(CO)_7~+, trinuclear Cu_3(CO)_7~+, Cu_3(CO)_8~+, and Cu_3(CO)_9~+, and tetranuclear Cu_4(CO)_8 ~+ are measured via infrared photodissociation spectroscopy in the carbonyl stretching frequency region. The structures are established by comparison of the experimental spectra with simulated spectra derived from density functional calculations. The Cu _2(CO)_6~+ cation is characterized to have an unbridged D_(3d) structure with a Cu-Cu half bond. The Cu _2(CO)_7~+ cation is determined to be a weakly bound complex involving a Cu_2(CO)_6~+ core ion. The trinuclear Cu_3(CO)_7~+ and Cu_3(CO)_8~+ cluster cations are determined to have triangle Cu_3 core structures with C_2 symmetry involving two Cu(CO)_3 groups and one Cu(CO)_x group (x = 1 or 2). In contrast, the trinuclear Cu_3(CO)_9~+ cluster cation is determined to have an open chain-like (OC)_3Cu-Cu(CO)_3-Cu(CO)_3 structure. The tetranuclear Cu_4(CO)_8~+ cluster cation is characterized to have a tetrahedral Cu_4~+ core structure with all carbonyl groups terminally bonded.