Electronic Control of RuII Complexes with Proximal Oxophilic Phenylselenium Tethers: Synthesis, Characterization, and Activation of Molecular Oxygen

Various ruthenium(II) complexes with proximal oxophilic phenylselenium groups of the general formula [Ru^IIL^AL^B]X₂{L^A= L^B= 6,6′-bis[(4-methoxyphenyl)selanyl]-2,2′-bipyridine; 6,6′-bis[(nitrophenyl)selanyl]-2,2′-bipyridine; 3,6-bis(phenylselanyl)dipyrido[3,2-a:2′,3′-c]phenazine; L^A= 6,6′-bis(phenylselanyl)-2,2′-bipyridine, L^B= terpyridine} were prepared. The substitution patterns of these compounds were designed to have different electron-withdrawing/-donating properties or different binding motifs in comparison to the previously reported compound with L^A= L^B= 6,6′-bis(phenylselanyl)-2,2′-bipyridine. The research objective was to evaluate the potential of these compounds to activate ground-state molecular oxygen to form higher-valent Ru–O–Se bonds by cleavage of the O–O bond of O₂. All of the compounds prepared indeed activated O₂to form Ru–O–Se moieties, as observable by UV/Vis spectroscopy, mass spectrometry, or X-ray crystallography.