New Ruthenium Carbonyl Clusters Containing Unusual μ5-Sulfido-, μ4-Benzyne-, and Thianthrene-Derived Ligands: Insertion of Ruthenium into the Thianthrene Ring by C−S Activation

Treatment of [Ru3(CO)12] with thianthrene in refluxing toluene afforded [(μ4-S)Ru4(μ-CO)2(CO)9(μ4-η2-C6H4)] (1), [(μ5-S)Ru6(μ-CO)2(CO)15(μ-η3-C12H8S)] (2), and [(μ5-S)Ru5(μ-CO)2(CO)11(μ-η3-C12H8S)(μ4-η2-C6H4)] (3) in 18%, 8%, and 16% yields, respectively. Thermolysis of 2 in refluxing heptane gave compounds 1 and 3. A similar thermolysis of 3 in refluxing toluene gave 1 in 90% yield. Treatment of 3 with neat MeCN afforded the labile compound [(μ5-S)Ru5(μ-CO)2(CO)10(μ-η3-C12H8S)(μ4-η2-C6H4)(MeCN)] (4) in 73% yield. The reaction of 4 with P(OMe)3 gave the substitution product [(μ5-S)Ru5(μ-CO)2(CO)10(μ-η3-C12H8S)(μ4-η2-C6H4){P(OMe)3}] (5) in 52% yield. Compounds 1−4 have been structurally characterized. Compound 1 contains a μ4-capping sulfido and a μ4-η2-benzyne ligand, whereas 3, 4, and 5 contain μ5-sulfido and μ4-η2-benzyne ligands. The latter three compounds provide rare examples of μ5-sulfido and metal-assisted opening of the thianthrene ligand on polynuclear centers. In compounds 1, 3, and 4 the μ4-η2-benzyne ligand is perpendicular to the Ru4 face of the clusters and represents a previously uncharacterized bonding mode for benzyne.