Matrix Infrared Spectroscopy and Quantum-Chemical Calculations for the Coinage-Metal Fluorides: Comparisons of Ar-AuF, Ne-AuF, and Molecules MF sub(2) and MF sub(3)

The reactions of laser-ablated Au, Ag, and Cu atoms with F sub(2) in excess argon and neon gave new absorptions in the M-F stretching region of their IR spectra, which were assigned to metal-fluoride species. For gold, a Ng-AuF bond was identified in mixed neon/argon samples. However, this bonding was much weaker with AgF and CuF. Molecules MF sub(2) and MF sub(3) (M=Au, Ag, Cu) were identified from the isotopic distribution of the Cu and Ag atoms, comparison of the frequencies for three metal fluorides, and theoretical frequency calculations. The AuF sub(5) molecule was characterized by its strongest stretching mode and theoretical frequency calculations. Additional evidence was observed for the formation of the Au sub(2)F sub(6) molecule. To coin a phrase: Experiments in solid neon and argon under cryogenic conditions led to the formation and characterization of MF sub(2) and MF sub(3) molecules (M=Au, Ag, Cu), NgAuF complexes (Ng=Ne, Ar), and AuF sub(5) (see figure), whilst also providing evidence for the formation of Au sub(2)F sub(6). IR spectra were in excellent agreement with state-of-the-art quantum-chemical calculations.