Alkyne complexes of molybdenum(II) and tungsten(II) containing acyclic and cyclic thioether ligands; crystal structures of [WI2(CO)- {MeS(CH2)2S(CH2)2SMe-S,S′}(η2-PhC2Ph)], [MoI(CO)([9]aneS3-S,S′,S″)(η2-PhC2Ph)]I and [WI(ttoc-S,S′,S″)(η2-PhC2Ph)2]I3 (ttoc = 2,5,8-trithia[9]orthocyclophane)

Abstract

Reaction of equimolar quantities of [MX₂(CO)(NCMe)(η²-RC₂R)₂] and MeS(CH₂)₂S(CH₂)₂SMe (ttn) in CH₂Cl₂ at room temperature gave the complexes [MI(CO)(ttn-S,S′,S″)(η²-RC₂R)]I·Et₂O (M = Mo, X = I, R = Me 1 or Ph 3; M = W, X = I, R = Me 2; M = W, X = Br, R = Ph 4), as the only isolated products, whereas treatment of equimolar amounts of [WI₂(CO)(NCMe)(η²-PhC₂Ph)₂] with ttn initially gave the crystallographically characterised complex [WI₂(CO)(ttn-S,S′)(η²-PhC₂Ph)] 5, which after reflux in CH₂Cl₂ afforded [WI(CO)(ttn-S,S′,S″)(η²-PhC₂Ph)]I 6. The crystal structure of 5 showed that the ttn ligand is attached to the tungsten by two adjacent sulfur atoms, leaving the third unco-ordinated. Equimolar quantities of 5 and [FeI(CO)₂(η-C₅H₅)] gave the bimetallic complex [WI₂(CO){MeS(CH₂)₂S(CH₂)₂SMe-S,S′,S″}(η²-PhC₂Ph){Fe(CO)₂(η-C₅H₅)}]I 7. Reaction of equimolar quantities of [MoI₂(CO)(NCMe)(η²-PhC₂Ph)₂] and Ph₂P(S)CH₂P(S)Ph₂ yielded the neutral complex [MoI₂(CO){Ph₂P(S)CH₂P(S)Ph₂-S,S′}(η²-PhC₂Ph)] 8. Treatment of equimolar amounts of [MoI₂(CO)(NCMe)(η²-RC₂R)₂] with 1,4,7-trithiacyclononane ([9]aneS₃) gave [MoI(CO)([9]aneS₃-S,S′,S″)(η²-RC₂R)₂]I (R = Me 9 or Ph 10). Complex 10 was crystallographically characterised and shows a molybdenum atom bonded to the three sulfurs of [9]aneS₃. Its geometry is best considered as a distorted octahedron with the diphenylacetylene occupying one site. Reaction of [MX₂(CO)(NCMe)(η²-RC₂R)₂] with an equimolar amount of 2,5,8-trithia[9]orthocyclophane (ttoc) afforded the salt complexes [MX(CO)(ttoc-S,S′,S″)(η²-RC₂R)]X 11–15 (M = Mo or W; X = I, R = Me or Ph; M = W, X = Br, R = Ph). The complex [WI(CO)(ttoc-S,S′,S″)(η²-PhC₂Ph)]I 14 was transformed in CH₂Cl₂ in the presence of PhC₂Ph to give the crystallographically characterised [WI(ttoc-S,S′,S″)(η²-PhC₂Ph)₂]I₃ 16 in very low yield. The structure is best considered as a distorted octahedron with the diphenylacetylenes each occupying one site. The shortest W–S bond is for the unique sulfur atom of ttoc trans to iodide.