DFT Studies on Reactions of Transition Metal Complexes with O2

DFT calculations have been carried out to study the mechanisms for reactions of O 2 with a series of metal complexes, including d 6 CpRuL 2, d 6 ML 5, and d 8 ML 4 complexes. The calculation results indicate that the reaction is initiated by an end-on coordination of O 2 to the metal center, which gives an (η 1 -O 2 )[M] intermediate. The uncoordinated oxygen atom of the η 1 -O 2 ligand then approaches the metal center to give a new η 1 -O 2 intermediate in which the η 1 -O 2 ligand is oriented approximately the same as the one defined in the product. An intersystem conversion from the triplet to singlet energy surface (MECP) then occurs to enable the metal peroxide product to be formed.