Theoretical studies on metal-metal interaction and luminescence of a dinuclear [AuS2PH2]2 complex

The ground- and excited-state structures of [AuS2PH2]2 are optimized by the MP2 and CIS methods, respectively. The calculated Au-Au distances of [AuS2PH2]2 indicate the presence of metallophilic attraction between the two Au atoms, which is weak in the ground state structure (Au-Au distance: 3.073 Å) but greatly enhanced in the lowest-energy triplet excited-state structure (Au-Au distance: 2.716 Å). On the basis of the MP2- and CIS-optimized structures, the TD-DFT method is employed to calculate the spectra of [AuS2PH2]2 and the results show that [AuS2PH2]2 possesses the 1,3[dσ∗(Au)sσ(Au)] lowest-energy excited states. In the luminescence, the Au-Au interaction plays a key role and the strong Au-Au interaction can result in a red shift to the visible region.