Infrared Photodissociation Spectroscopy of Mass-Selected Silver and Gold Nitrosyl Cation Complexes

The [M(NO)n]+ cation complexes (M = Au and Ag) are studied for exploring the coordination and bonding between nitric oxide and noble metal cations. These species are produced in a laser vaporization supersonic ion source and probed by infrared photodissociation spectroscopy in the NO stretching frequency region using a collinear tandem time-of-flight mass spectrometer. The geometric and electronic structures of these complexes are determined by comparison of the distinctive experimental spectra with simulated spectra derived from density functional theory calculations. All of these noble metal nitrosyl cation complexes are characterized to have bent NO ligands serving as one-electron donors. The spectrum of [Au(NO)2Ar]+ is consistent with 2-fold coordination with a near linear N–Au–N arrangement for this ion. The [Au(NO)n]+ (n = 3–4) cations are determined to be a mixture of 2-fold coordinated form and 3- or 4-fold coordinated form. In contrast, the spectra of [Ag(NO)n]+ (n = 3–6) provide evidence for the...