Complexes of unsaturated phosphines.

Some reactions of Group VIII complexes of unsaturated phosphines are described. The project falls into three parts. The first section deals with various aspects of the preparation of unsaturated phosphines and includes a review of the factors effecting the course of the reaction between metal phosphides and alkyl halides. An improved method of generating lithium dialkylphosphide is described, using naphthalene as a catalyst for the cleavage of tetra-alkyldiphosphine in tetrahydrofuran. Using this technique several new dialkylphosphino derivatives have been prepared. As an alternative route to 1,4-bis(dimethylphosphino)but-2-ene, the addition of tetramethyl-diphosphine to butadiene was investigated; the course and the mechanism of this reaction are discussed. This section also includes the first reported preparation of B-acetylenic phosphines, and their rearrangement is described. The preparation of platinum(II) and palladium(II) complexes of unsaturated phosphines, together with a discussion of their structures, is described in the second section. It is apparent that whether there is co-ordination from the olefin or acetylene group to the metal in addition to that from the phosphorus depends on the length of the carbon chain between the two donors. Novel dimeric structures are suggested for the complexes of l,4-bis(phosphino)but-2-enes. In the third section are described the reactions of the methoxide ion with olefins activated by co-ordination to platinum(II), and with olefins and acetylenes unco-ordinated to, but in the environment of, platinum(II). The physical and chemical evidence for the unusual structures involving platinum- carbon o-bonds which are suggested for the resulting complexes is discussed.