Pressure-Induced Phase Transition in Quasi-1D
Mixed-Valence Gold Complexes

Abstract

Pressure effects on Raman spectra have been investigated in quasi-one-dimensional (quasi-1D) mixed-valence (MV) gold complexes [AuX(DBS)][AuX₃(DBS)] (X=Br and Cl, DBS=dibenzylsulfide) at 300K. We have observed pressure-induced deactivation of a Raman-active Au-X stretching mode, indicating a pressure-induced phase transition from the MV state to a single-valence (SV) state. The critical pressure P_c for the phase transition increases from ∼8GPa for X=Br to ∼17GPa for X=Cl, perhaps due to the enhanced displacement of halogen ions from the central position.