Facile E−E and E−C Bond Activation of PhEEPh (E = Te, Se, S) by Ruthenium Carbonyl Clusters: Formation of Di- and Triruthenium Complexes Bearing Bridging dppm and Phenylchalcogenide and Capping Chalcogenido Ligands

Abstract

Reactions of [Ru3(CO)10(μ-dppm)] (1) and its ortho-metalated derivative [Ru3(CO)9{μ3-η3-P(C6H5)CH2P(C6H5)(C6H4)}] (11) with PhEEPh (E = Te, Se, S) have been investigated. Treatment of 1 with PhTeTePh at room temperature afforded the dinuclear compound [Ru2(CO)4(μ-TePh)2(μ-dppm)] (2) and the 54-electron triruthenium compounds [Ru3(CO)6(μ3-Te)2(μ-TePh)2(μ-dppm)] (3) and [Ru3(CO)6(μ3-Te)(μ-TePh)3(η1-COPh)(μ-dppm)] (4). Analogous reactions of 1 with PhEEPh (E = Se, S) led to [Ru2(CO)4(μ-EP[Ru3(CO)6(μ3-E)2(μ-EPh)2(μ-dppm)])2(μ-dppm)] (E = Se, 5; E = S, 8) and the 54-electron triruthenium compounds (E = Se, 6; E = S, 9), and [Ru3(CO)6(μ3-E)(μ-EPh)3(Ph)(μ-dppm)] (E = Se, 7; E = S, 10). Reactions of the ortho-metalated complex 11 with PhEEPh (E = Te, Se, S) in refluxing THF gave exclusively [Ru3(CO)6(μ-EPh)2{μ3-η3-P(C6H5)CH2P(C6H5)(C6H4)}] (E = Te, 12; E = Se, 13; E = S, 14). The new compounds have been characterized by a combination of analytical and spectroscopic methods, and molecular structures of 2−4, 7, 10, and 13 have been determined by single-crystal X-ray diffraction studies. Compounds 2, 5, and 8 have the classical “sawhorse” structure with two bridging EPh (E = Te, Se, S) moieties and one bridging dppm ligand. Compounds 3, 6, and 9 contain a Ru3 framework with two bridging EPh (E = Te, Se, S) groups, one bridging dppm ligand, and two capping chalcogenido ligands. Compound 4 contains an Ru3 core with a capping tellurido ligand, three bridging TePh moieties, one bridging dppm ligand, and a terminally coordinated benzoyl group, formed from multiple fragmentation of the PhTeTePh ligand and migratory insertion of a Ph group into a CO ligand. Compounds 7 and 10 comprise a capping chalcogenido ligand, three bridging EPh (E = Se, 7; E = S, 10) moieties, a bridging dppm ligand, and a terminally coordinated σ-bonded phenyl group. In compounds 12–14, the coordination of ortho-metalated diphosphine ligand is the same as in 11 and both the EPh moieties bridge the same unbridged Ru−Ru edge. Compounds 3, 6, 7, and 10 exhibit restricted fluxional behavior involving the μ-EPh moieties.