The crystal structure of [Mo(NCS)(CO)2(η3-C3H5) (NCMe)2].MeCN and the reactions of {Mo(CO)2 (η3-C3H5)+} containing species with symmetric alkynes

Article abstract of DOI:10.1016/S0022-328X(02)01981-2

In the solid-state about molybdenum, with carbonyls and nitriles in the equatorial plane and an N-bonded thiocyanate group trans to the allyl ligand. In refluxing methanol or acetonitrile both 1, and the analogous chloro-complex [MoCl(CO)₂(η³-C₃ H₅)(NCMe)₂](2) catalytically convert PhC≡CPh to a mixture of hexaphenylbenzene and E,E-1,2,3,4-tetraphenylbutadiene. By contrast MeO₂CC≡CCO₂Me is not oligomerised. In methanol, complex 2 dimerises 1,4-diphenylbutadiyne to Z,E-1,4,5,8-tetraphenyl-1,7-octa-3,5-diene-1,7-diyne, whereas in the presence of base both the complex and the diyne, react preferentially with the solvent to generate the [Mo₂(CO)₄ (η³-C₃H₅)₂ (OMe)₃]^- anion and Z-1,4-diphenyl-3- methoxy-but-3-ene-1-yne, respectively.