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).