The bis(aminophenol) 2,2'-biphenylbis(3,5-di-tert-butyl-2-hydroxyphenylamine) (ClipH(4)) forms trans-(Clip)Os( py)(2) upon aerobic reaction of the ligand with {(p-cymene)OsCl2}(2) in the presence of pyridine and triethylamine. A more oxidized species, cis-beta-(Clip)Os(OCH2CH2O), is formed from reaction of the ligand with the osmium(VI) complex OsO(OCH2CH2O)(2), and reacts with Me3SiCl to give the chloro complex cis-beta-(Clip)OsCl2. Octahedral osmium and ruthenium tris-iminoxolene complexes are formed from the chelating ligand tris(2-(3',5'-di-tert-butyl-2'-hydroxyphenyl)amino-4-methylphenyl)amine (MeClampH(6)) on aerobic reaction with divalent metal precursors. The complexes' structural and electronic features are well described using a simple bonding model that emphasizes the covalency of the pi bonding between the metal and iminoxolene ligands rather than attempting to dissect the parts into discrete oxidation states. Emphasizing the continuity of bonding between disparate complexes, the structural data from a variety of Os and Ru complexes show good correlations to p bond order, and the response of the intraligand bond distances to the bond order can be analyzed to illuminate the polarity of the bonding between metal and the redox-active orbital on the iminoxolenes. The osmium compounds' p bonding orbitals are about 40% metal-centered and 60% ligand-centered, with the ruthenium compounds' orbitals about 65% metal-centered and 35% ligand-centered.
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