Ruthenium terpyridine complexes with mono- and bi-dentate dithiolene ligands

The reaction of [Ru(CO)(2)Cl(terpy)]PF6 (terpy=2,2':6':2"-terpyridine) with Na(2)mnt (mnt=S2C2(CN)(2)) initially produced [Ru(CO)(2)(mnt-kappaS)(terpy-kappa (NN)-N-3'N)] 1a, which rearranged to [Ru(CO)(2)(mnt-kappa (SS)-S-2')(terpy-kappa (NN)-N-2)] 1b in solution. The molecular structures of 1a and 1b indicate that the rearrangement proceeds via a five-coordinated complex with monodentate mnt and bidentate terpy. The reaction of [Ru(CO)(2)Cl(terpy)]PF6 with 3,4-toluenedithiol (H(2)tdt) gave [Ru(CO)(2)(tdt-kappa (SS)-S-2)(terpy-kappa (NN)-N-2)] 2b but [Ru(CO)(2)(tdt-kappaS)(terpy-kappa (NN)-N-3'N)] 2a was not identified. Thus, ruthenium complexes with bidentate dithiolene and bidentate terpyridine seem to be more stable than those with monodentate dithiolene and tridentate terpyridine. Neither [Ru(CO)(2)(pdt-kappaS)(terpy-kappa (NN)-N-3'N)] 3a nor [Ru(CO)(2)(pdt-kappa S-2)(terpy-kappa (NN)-N-2')] 3b (pdt=PhC(S)C(S)Ph) was obtained in the reaction of [Ru(CO)(2)Cl(terpy)]PF6 with the Cs+ salt of pdt(2-) in CH3OH under N-2. The same reaction conducted under aerobic conditions afforded [Ru(CO)(C(O)OCH3)(SC(Ph)C(Ph)SC(O)OMe)(terpy-kappa (NN)-N-3'N")] 3 resulting from double addition of CO2 and CH3OH to the terminal sulfur of pdt and a carbonyl carbon of 3a, respectively, followed by esterification of the resultant [Ru(CO)(C(O)OCH3)(SC(Ph)C(Ph)SC(O)OH)(terpy-kappa (NN)-N-3'N")] in CH3OH. The addition of CO2 to the sulfur of 3a is ascribed to the strong basicity and weak chelating ability of pdt compared with those of mnt and tdt. A series of [RuX(dithiolene)(terpy)](n+) (X=dmso, Cl or OSO2CF3; n=0 or 1) were also prepared.