Theoretical study of photochromic dinuclear molybdenum complexes

摘要

In order to elucidate the mechanism of photochromism observed for [Mo_2(#mu#-S_2)(#mu#-S_2C_2Ph_2)_2(S_2C_2Ph_2)_2] (1a), the model complexes of 1a and [Mo_2(#mu#-S_2)_2(#mu#-S_4)(S_2C_2Ph_2)_2] (2a), in which all phenyl groups are replaced by hydrogens, have been optimized by using ab initio and hydrid DFT (B3LYP) programs. We found that B3LYP/3-21G~* afforded the best results, so that the hydrid DFT should be a useful tool for the transition metal complexes. The photochromic property originates from the isomerization at the lowest excited state, and the analysis of this electronic properties suggests that the CT transition from the #pi#-orbitals of the bridged ethylene-1,2-dithiolate ligand to Mo d-orbitals of 1a would trigger the isomerization.