Reaction between [Ru3(CO)12] and the tridentate phosphine ligand HC(PPh2)3; X-ray crystal structures of complexes [Ru3(CO)9{Ph2PCHP(Ph)C6H4PPh}], [Ru2H(CO)4(Ph2PCHPPh2){PhPC6H4C(O)}], and [Ru2(CO)4Cl(PPh2)(dppm)]
Abstract
From the reaction of [Ru3(CO)12] with HC(PPh2)3 the symmetrically capped product [Ru3(CO)9{HC(PPh2)3}](1) has been isolated in low yield, together with five other complexes, [Ru3(CO)9{Ph2PCHP(Ph)C6H4PPh}](2), [Ru2(CO)5Ph{(Ph2P)2C(H)PPh}](3), [Ru2(CO)4Cl(PPh2)(dppm)](4)(dppm = Ph2PCH2PPh2), [Ru2H(CO)4(Ph2PCHPPh2)(PhPC6H4)](5), and [Ru2H(CO)4(Ph2PCHPPh2){PhPC6H4C(O)}](6). Complexes (1)–(6) have been characterised by i.r.,1H, 31P, and 13C n.m.r. spectroscopy. In addition, the structures of complexes (2), (4), and (6) have been determined by single-crystal X-ray diffraction methods. In (2), the HC(PPh2)3 ligand has undergone a reaction of which the end result is an ortho-substitution of a phenyl ring of one phosphine moiety by the phosphorus atom of a second phosphine moiety, together with the loss of C6H6. The resulting Ph2PC(H)P(Ph)C6H4P(Ph) ligand caps the Ru3 triangle. In (4), the dppm, the PPh2, and the chloride ligands all bridge the Ru–Ru bond. In (6), the Ph2PCHPPh2 ligand bridges the Ru–Ru bond, and the central carbon atom is also bonded to one of the Ru atoms to form a three-membered Ru–P–C ring. Also bridging the Ru–Ru bond is a hydride and a PhPC6H4C(O) ligand with which both Ru atoms form bonds to the phosphorus atom and one of the Ru atoms is also bonded to the acyl carbon to form a functional acyl ligand. Pathways to all these complexes are proposed.