Studies on the reactions of ruthenium(II) substrates with tridentate (N,N,O) azo ligands

Reactions of 1-{[2-(arylazo)phenyl]iminomethyl}-2-phenol, HLsal, 1, [where H represents the dissociable protons upon complexation and aryl groups of HLsal are phenyl for HL1sal, p-methylphenyl for HL2sal, and p-chlorophenyl for HL3sal], ligands with Ru(H)(CO)(Cl)(PPh3)3 afforded complexes of composition [(Lsal)Ru(CO)(Cl)(PPh3)] and (Lsal)2Ru where the N,N,O donor tridentate (Lsal)− ligands coordinated the metal centre facially and meridionally, respectively. Stepwise formation of [(Lsal)2Ru] has been ascertained. Reaction of 1-{[2-(arylazo)phenyl]iminomethyl}-2-napthol, HLnap, 2, [where H represents the dissociable protons upon complexation and aryl groups of HLnap are phenyl for HL1nap, p-methylphenyl for HL2nap, and p-chlorophenyl for HL3nap], ligands with Ru(H)(CO)(Cl)(PPh3)3 afforded exclusively the complexes of composition [(Lnap)Ru(CO)(Cl)(PPh3)], where N,N,O donor tridentate (Lnap)− was facially coordinated. The ligand 1-{[2-(phenylazo)phenyl]aminomethyl}-2-phenol, HL, 3, was prepared by reducing the aldimine function of HL1sal. Reaction of HL with Ru(PPh3)3Cl2 afforded new azosalen complex of Ru(III) in concert with regiospecific oxygenation of phenyl ring of HL. All the new ligands were characterized by analytical and spectroscopic techniques. The complexes were characterized by analytical and spectroscopic techniques and subsequently confirmed by the determination of X-ray structures of selected complexes.