Concerning the Ground State and S1 and T1 Photoexcited States of the Homoleptic Quadruply Bonded Complexes Mo_2(O_2CC_6H_4?p?X)_4, where X = CC?H or CN

摘要

The preparation of the homoleptic MM quadruply bonded complexes Mo_2(O_2CC_6H_4-p-X)_4, where X = CC?H (I) or CN (II), is reported along with the solution characterization data and electronic structure calculations employing density functional theory. The compounds are colored orange (I) and red (II) due to the metal-to-ligand charge transfer involving the HOMO, Mo_2δ, and LUMO, which is a ligand-based π* combination. Studies of the S_1 state, 1MLCT, by femtosecond time-resolved infrared spectroscopy indicate that the negative charge is distributed principally over two trans ligands. The T_1 states are 3Mo- Moδδ* as determined by NIR emission and nanosecond transient absorption.