PRIMARY ALKENYL PHOSPHINE COMPLEXES OF CHROMIUM AND MOLYBDENUM - SYNTHESIS AND CHARACTERIZATION OF CARBONYL(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)chro mium tricarbonyl complexes. Radical-catalysed coupling of the allyl fu nctions with PH groups in the tris(allylphosphine) complex led to the chromium tricarbonyl complex of 1,5,9-triphosphacyclododecane. The mol ybdenum 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 multident ate ligand systems but not in complexes of new macrocycles. The crysta l structures of the new 1,5,9-triphosphacyclododecane and prop-2-enylp hosphine complexes have been determined and Structural implications fo r these template cyclisation reactions investigated.