title: Electronic and resonance Raman spectra of [Au2(CS3)2]2-. Spectroscopic properties of a "short" Au(I)-Au(I) bond.
abstract: The anion [Au2(CS3)2]2- has an unusually short Au-Au distance (2.80 A) for a binuclear Au(I) complex. We report detailed Raman studies of the nBu4N+ salt of this complex, including FT-Raman of the solid and UV/vis resonance Raman of dimethyl sulfoxide solutions. All five totally symmetric vibrations of the anion have been located and assigned. A band at delta nu = 125 cm-1 is assigned to nu (Au2). The visible-region electronic absorption bands (384 (epsilon 30,680) and 472 nm (epsilon 610 M-1 cm-1)) are attributable to CS3(2-) localized transitions, as confirmed by the dominance of nu sym(C-Sexo) (delta nu = 951 cm-1) in RR spectra measured in this region. An absorption band at 314 nm (22,250 M-1 cm-1) is assigned as the metal-metal 1(d sigma*-->p sigma) transition, largely because nu sym(C-Sexo) is not strongly enhanced in RR involving this band. Observation of the expected strong resonance enhancement of nu (Au2) was precluded as a result of masking by intense solvent Rayleigh scattering in the UV.
authors.affiliation: Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong.
authors.forename: E C
authors.initials: EC
authors.lastname: Cheng
authors.forename: K H
authors.initials: KH
authors.lastname: Leung
authors.forename: V M
authors.initials: VM
authors.lastname: Miskowski
authors.forename: V W
authors.initials: VW
authors.lastname: Yam
authors.forename: D L
authors.initials: DL
authors.lastname: Phillips