New ruthenium complexes from Ru3(CO)12 and 6-Alkyl- or 6-Phenyl-2-hydroxypyridines

Trirutheniumdodecacarbonyl (Ru3(CO)12) reacts with 2-hydroxy-6-methylpyridine and with 2-hydroxy-5,6,7,8-tetrahydroquinoline in toluene to form centrosymmetric tetranuclear complexes of the type [Ru(η2, μ-L)(CO)2(μ3-L)Ru(CO)2]2, where L is the respective (N,O)-pyridonate ligand (2 and 3). The structures of these complexes, which are almost insoluble in all common solvents, could be determined by single-crystal X-ray diffraction. Reaction of Ru3(CO)12 with 2-hydroxy-4,6-diphenylpyridine in methanol includes ortho-metallation at the phenyl ring, furnishing the dinuclear complex [Ru(κ2N,C–L)(CO)2(μ-OCH3)2Ru(CO)2 (κ2N,C–L)] (4), where L = (2-(6-hydroxy-4-phenylpyridin-2-yl)phenyl), according to an X-ray crystal structure determination.