Reactions of 5-RC2R)2> (R=Me or Ph) with carbon monoxide to give either 2-MeC2Me)2> or 2-PhC2Ph)2>2. Crystal structure of 2-MeC2Me)2>

Article abstract of DOI:10.1016/0022-328X(87)85197-5

The complexes 2-RC2R)2> (R=Me and Ph) react in CH2Cl2 with an excess of carbon monoxide to give initially the acetonitrile substituted products 2-RC2R)2>.For R=Me, the complex 2-MeC2Me)2> (1) was isolated and its structure determined by X-ray crystallography.However, for R=Ph, dimerisation occurs to give the iodide-bridged compound 2-PhC2Ph)2>2 (2) with loss of carbon monoxide.These reactions are reversible as 1 and 2 react with acetonitrile to give 2-RC2R)2>.The 13C NMR spectra of 1 and 2 indicate that the two alkyne ligands donate a total of six electrons to the tungsten in these complexes.