Reactivity of the zwitterionic ligand EtNHC(S)Ph2PNPPh 2C(S)NEt towards [Ru3(CO)12]. Sulfur transfer and ligand fragmentation leading to the methideylamide [-N(Et)-CH(R)-] μ3-bridging moiety

The reaction of EtNHC(S)Ph2PNP+Ph2C(S) N-Et (HEtSNS) with [Ru3(CO)12] has been carried out under two different experimental conditions: in the first case [Ru 3(CO)12], previously turned into the labile intermediate [Ru3(CO)10(CH3CN)2], afforded, at room temperature in dichloromethane, the trinuclear clusters [Ru 3(CO)11(CNEt)] (1), {Ru3(CO) 9(μ-H)[(μ-S:κ-P)Ph2PNPPh2C(S)NEt]} (2), {Ru3(CO)9(μ-H)[(μ-S:κ-P)Ph 2PNP(S)Ph2]} (3) and {Ru3(CO) 10[(μ-κ2P)Ph2PNHPPh2]} (4). Ligand fragmentation occurs via loss of EtNC or EtNCS, without sulfur transfer to the cluster core. In the second case, [Ru3(CO)12] reacted with HEtSNS in toluene at 70 °C, giving the trinuclear clusters 4, {Ru3(CO)7(CNEt)(μ3-S)[(μ2-N: η1-C:κ1-P)Ph2PNPPh 2C(H)NEt]} (5), {Ru3(CO)8)(μ3-S) [(μ2-N:η-C:κ-P)Ph2PNPPh2C(H)NEt]} (6) and {Ru3(CO)6(μ3-CO)(μ3-S) (EtNC)[(μ-κ2P) Ph2PNHPPh2]} (7). The last three compounds derive from ligand fragmentation and sulfur transfer to the metal cluster. All compounds were characterized by spectroscopy (NMR, IR) and the molecular structures of 2, 5 and 7 were determined by single-crystal X-ray diffraction. Cluster 2 preserves the original Ru3 triangular core in which an edge is bridged by a hydride ligand and by the sulfur atom of the Ph2PNPPh2C(S)NEt ligand. Cluster 5 shows an open triangle of Ru atoms capped by a μ3-sulfide and by the unprecedented methideylamide -N(Et)CH(R)-μ3-bridging moiety of the Ph 2PNPPh2C(H)NEt ligand. It formally derives from cluster 6 by substitution of ethyl isonitrile with one CO molecule. Finally, cluster 7 displays a Ru3(μ3-S)(μ3-CO) trigonal bipyramidal core. © 2009 The Royal Society of Chemistry.