Pressure-induced phase transition in quasi-1D mixed-valence gold complexes

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 300 K. 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 similar to 8GPa for X = Br to similar to 17GPa for X = Cl, perhaps due to the enhanced displacement of halogen ions from the central position.