3-Hexyne complexes of molybdenum(II) and tungsten(II) containing phosphite ligands: X-ray crystal structures of [MoI2(CO)(NCMe){P(OPh)3}(η2-EtC2Et)], [MoI2(CO)(dppe)(η2-EtC2Et)] and [MI2(CO){P(OiPr)3}2(η2-EtC2Et)] (M=Mo and W)

Equimolar quantities of [MoI2(CO)(NCMe)(η2-EtC2Et)2] and P(OR)3 (R=Ph, iPr) gave the 3-hexyne displaced products, [MoI2(CO)(NCMe){P(OR)3}(η2-EtC2Et)] (1) and (2), which was crystallographically characterised for R=Ph. By contrast, reaction of equimolar quantities of [WI2(CO)(NCMe)(η2-EtC2Et)2] and P(OR)3 (R=Me, iPr, Ph) afforded the acetonitrile displaced products, [WI2(CO){P(OR)3}(η2-EtC2Et)2] (3 to 5). The reactions of the mono(triphenylphosphite)molybdenum complex, [MoI2(CO)(NCMe){P(OPh)3}(η2-EtC2Et)] (1) with a series of neutral mono, bidentate and anionic dithiocarbamate ligands have been investigated to give a variety of reaction products, including [MoI2(CO)(dppe)(η2-EtC2Et)] (12), which has been structurally characterised. Reaction of [MI2(CO)(NCMe)(η2-EtC2Et)2] with two equivalents of P(OR)3 gave the mono(3-hexyne) complexes, [MI2(CO){P(OR)3}2(η2-EtC2Et)] {M=Mo or W; R=Me, Et, iPr, nBu, Ph(for M=W only)} (15 to 23), which were crystallographically characterised for M=Mo and W, R=iPr 19 and 20, respectively.