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)(eta (2)-EtC2Et)(2)] and P(OR)(3) (R =Ph, ' Pr) gave the 3-hexyne displaced products, [MoI2(CO)(NCMe){P(OR)(3)}(eta (2)-EtC2Et)] (1) and (2), which was crystallographically characterised for R = Ph. By contrast, reaction of equimolar quantities of [WI2(Co)(NCMe)(eta (2)-EtC2Et)(2)] and P(OR)(3) (R = Me, ' Pr, Ph) afforded the acetonitrile displaced products, [WI2(CO){P(OR)(3)} (eta (2)-EtC2Et)(2)] (3 to 5). The reactions of the mono(triphenylphosphite)molybdenum complex, [MoI2(CO)(NCMe){P(OPh)(3)}(eta (2)-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)(eta (2)-EtC2Et)] (12), which has been structurally characterised. Reaction of [MI2(CO)(NCMe)(eta (2)-EtC2Et)(2)] with two equivalents of P(OR)(3) gave the mono(3-hexyne) complexes, [MI2(CO){P(OR)(3)}(2)(eta (2)-EtC2Et)] {M = Mo or W; R = Me, Et, ' Pr, " Bu, Ph(for M = W only)} (15 to 23), which were crystallographically characterised for M = Mo and W, R = ' Pr 19 and 20, respectively. (C) 2001 Elsevier Science B.V. All rights reserved.