Dinuclear ruthenium(II) catecholato and 2,3-naphthalenediolato complexes featuring κ2-diaryloxo/η6-arene coordination mode

A new dinuclear ruthenium(II) catecholato complex [Cp*Ru(κ2:η6-μ2-1,2-O2C6H4)RuCp*] (3; Cp* = η5-C5Me5) has been prepared by the reaction of [Cp*RuCl]4 with 2 equiv. of disodium catecholate in THF. Complex 3 has a dinuclear structure, in which one of the Cp*Ru fragments is κ2-bonded to the two oxygen atoms and the other is η6-bonded to the aromatic ring. Similar treatment of [Cp*RuCl]4 with disodium 2,3-naphthalenediolate affords an analogous κ2:η6-bonded dinuclear complex [Cp*Ru(κ2:η6-μ2-2,3-O2C10H6)RuCp*] (4) with selective π-complexation at the oxygen-substituted naphthalene ring. The molecular structure of 4 has been determined by X-ray crystallography. The oxygen-bound ruthenium atoms in complexes 3 and 4 are coordinatively unsaturated and readily uptake 1 equiv. of carbon monoxide to give the corresponding carbonyl adducts [Cp*Ru(CO)(κ2:η6-μ2-1,2-O2C6H4)RuCp*] (5) and [Cp*Ru(CO)(κ2:η6-μ2-2,3-O2C10H6)RuCp*] (6), respectively.