Electronic structure and catalytic aspects of [(trpy)(Cl)Ru(L)]n incorporating potential non-innocent ligands, L−: 9-Oxidophenalenone and trpy: 2,2′:6′,2″-terpyridine

Abstract

The title complex [(trpy)(Cl)RuII(L)] (1) incorporating potential redox non-innocent ligands, L−=9-oxidophenalenone and trpy=2,2′:6′,2″-terpyridine has been structurally characterized. The crystal structure of 1 establishes the distorted octahedral arrangement, meridional coordinating mode of trpy and delocalized C–O bond distances of coordinated L−. Compound 1 displays two one-electron oxidations at E2980, 0.12V (Ox1) and 1.32V (Ox2) and one reduction, −1.58V versus SCE. Predominantly ruthenium based first oxidation (Ox1) and L based second oxidation (Ox2) lead to the valence configurations of [(trpy)(Cl)RuIII(L−)]+ (1+) and [(trpy)(Cl)RuIII(L)]2+ (12+), respectively. The antiferromagnetic coupling of spins on Ru(III) (low-spin, t2g5) and L develops a singlet (S=0) ground state in 12+. The reduction, however, occurs at the trpy site. The electronic transitions in 1 and 1+ could be assigned based on the TD-DFT calculations. Interestingly, 1 has been established to be an efficient pre-catalyst for the oxidative cleavage of alkenes to carbonyl derivatives.