New ruthenium carbonyl clusters containing unusual mu(5)-sulfido-, mu(4)-benzyne-, and thianthrene-derived ligands: Insertion of ruthenium into the thianthrene ring by C-S activation

Treatment of [Ru-3(CO)(12)] with thianthrene in refluxing toluene afforded [(mu(4)-S)Ru-4(mu-CO)(2)(CO)(9)(mu(4)-eta(2)-C6H4)] (1), [(mu(5)-S)Ru-6(mu-CO)(2)(CO)(15)(mu-eta(3)-C12H8S)] (2), and [(mu(5)-S)Ru-5(mu-CO)(2)(CO)(11)(mu-eta(3)-C12H8S)(mu(4)-eta(2)-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 [(mu(5)-S)Ru-5(mu-CO)(2)(CO)(10)(mu-eta(3)-C12H8S)(mu(4)-eta(2)-C6H4)(Me CN)] (4) in 73% yield. The reaction of 4 with P(OMe)(3) gave the substitution product [(mu(5)-S)Ru-5(mu-CO)(2)(CO)(10)(mu-eta(3)-C12H8S)(mu(4)-eta(2)-C6H4){P( OMe)(3)}] (5) in 52% yield. Compounds 1-4 have been structurally characterized. Compound 1 contains a mu(4)-capping sulfido and a mu(4)-eta(2)-benzyne ligand, whereas 3, 4, and 5 contain mu(5)-sulfido and mu(4)-eta(2)-benzyne ligands. The latter three compounds provide rare examples of mu(5)-sulfido and metal-assisted opening of the thianthrene ligand on polynuclear centers. In compounds 1, 3, and 4 the mu(4)-eta(2)-benzyne ligand is perpendicular to the Ru-4 face of the clusters and represents a previously uncharacterized bonding mode for benzyne.