Primary alkenyl phosphine complexes of chromium and molybdenum; Synthesis and characterisation of tricarbonyl(1,5,9-triphosphacyclododecane)chromium(0)

The reaction of fac-[Cr(CO)(3)(MeCN)(3)] with primary allyl- and vinyl-phosphines gave rise to the corresponding tris(primary phosphine)chromium tricarbonyl complexes. Radical-catalysed coupling of the allyl functions with PH groups in the tris(allylphosphine) complex led to the chromium tricarbonyl complex of 1,5,9-triphosphacyclododecane. The molybdenum analogue of the chromium prop-2-enylphosphine complex has also been prepared. Radical-catalysed coupling of the vinyl functions with PH groups in these complexes resulted in new complexes with multidentate ligand systems but not in complexes of new macrocycles. The crystal structures of the new 1,5,9-triphosphacyclododecane and prop-2-enylphosphine complexes have been determined and Structural implications for these template cyclisation reactions investigated.