Theoretical study on the structure of the ground state and photo-induced metastable states of [M(CN)5NO]2− (M = Ru, Fe), and mechanism of the photo-rearrangement among them

Abstract

Abstract In this note, we reviewed theoretical investigations of the photo-induced metastable states and discussed possible photo-rearrangement paths in [M(CN)5NO]2− (M = Fe and Ru). Using calculated results of ab initio multi-reference single and double excitation configuration interaction calculations with Davidson type quadruple correction (MRSDCI + Q) and those of density fuctional theory (DFT), we showed that the two metastable states (MS1 and MS2) were local minima of the electronic ground state potential surface. The theoretical calculations supported the experimental observation of the structure of the three isomers (GS, MS1 and MS2), relative stability of MS1 and MS2. We discussed the character of the lower electronic excited states and excitation energies of the three isomers of both compounds. Based on these results and excited state adiabatic potential energy surfaces, possible mechanism of photo-rearrangement among GS, MS1, and MS2 were discussed with the aid of our results on [Mn(CN)5NO]3− of which no photo-rearrangement has been reported.