Photoelectron imaging and theoretical study on the structure and chemical binding of the mixed-ligand M(I) complexes, [HMSH]⁻ (M = Cu, Ag, and Au).

ABSTRACT

We have reported a combined photoelectron imaging and theoretical study on gaseous mixed-ligand M(I) complexes of [HMSH](-) (M = Cu, Ag, and Au). With the aid of Franck-Condon simulations, vibrationally resolved photoelectron spectra yield accurate electron affinities of 3.269(6), 3.669(10), and 3.591(6) eV for [HCuSH], [HAgSH], and [HAuSH], respectively. And low-frequency modes are observed 368(12) cm(-1) for [HCuSH], 286(12) cm(-1) for [HAgSH], and 327(12) cm(-1) for [HAuSH], respectively. Extensive theoretical calculations are performed to aid in the spectral assignments and the calculated values agree well with the experimental observations. Although the S and H atoms have little discrepancy in electronegativity (2.20 for H and 2.54 for S), distinct bonding properties are demonstrated between H-M and M-S bond. It is revealed that there exists significant ionic bonding between M-S in [HMSH](-) (M = Cu, Ag, and Au), while a gradual transition from ionic behavior between H-Cu in [HCuSH](-) to quite strong covalent bonding between H-Au in [HAuSH](-), supported by a variety of chemical bonding analyses.