Syntheses of Ru-S clusters with kinetically labile ligands via the photolysis of [(cymene)3RuS2](PF6)2

Three ruthenium sulfide clusters with labile CH3CN ligands have been photochemically synthesized. Irradiation of (cymene)3Ru3S2](PF6)2 (1](PF6)2) in CH3CN gives (cymene)2(CH3CN)3Ru3S2](PF6)2 (2](PF6)2), which has been characterized by 1H NMR spectroscopy, ESI mass spectrometry, and chemical reactivity. Treatment of 2](PF6)2 with PPh3 gives (cymene)2(CH3CN)2(PPh3)Ru3S2](PF6)2 (3](PF6)2) and (cymene)2(CH3CN)(PPh3)2Ru3S2](PF6)2 (4](PF6)2), while treatment with 1,4,7-trithiacyclononane (9S3) gives (cymene)2(9S3)Ru3S2](PF6)2 (5](PF6)2). A crystallographic study demonstrated that the Ru3 core in 3](PF6)2, 4](PF6)2, and 5](PF6)2 is distorted with a pair of elongated Ru-Ru bonds. Cyclic voltammetry shows that 3](PF6)2 and 4](PF6)2 undergo two closely spaced reversible one-electron reductions whereas 5](PF6)2 undergoes one irreversible one-electron reduction and one reversible one-electron reduction. Prolonged irradiation of 1](PF6)2 in CH3CN causes decomposition, resulting in the pentanuclear cluster (cymene)4Ru5S4](PF6)2 (6](PF6)2).