Synthesis and co-ordination chemistry of perfluorovinyl phosphine derivatives. Single crystal structures of PPh(CFCF2)2, cis-[PtCl2{PPh2(CFCF2)}2] and [{AuCl[PPh2(CFCF2)]}2

Abstract

Reaction of perfluorovinyllithium, derived from CF3CH2F, with chloro-substituted phosphines generated perfluorovinylphosphines of the type PPhm(CFCF2)n and P(CFCF2)nClm (n + m = 3) in high yields. A low-temperature crystal structure determination of the air- and moisture-stable compound PPh(CF=CF2)2 provided the first reported structural data for any perfluorovinyl-containing material. There is considerable variation in the C–F bond distances [1.310(4), 1.321(4), 1.353(3) A] within the perfluorovinyl group in the phosphine. The co-ordination chemistry of these ligands has been investigated via the synthesis of examples of late transition-metal complexes. The results of single crystal structural determinations of cis-[PtCl2{PPh2(CFCF2)}2] and [{AuCl[PPh2(CFCF2)]}2]·0.5CH2Cl2 are reported. In both of these molecules short metal–phosphorus distances [d(Pt–P)av = 2.231(3) and d(Au–P)av = 2.217(2) A] are observed compared with typical distances for similar phosphine complexes. A comparison of the electronic properties of these ligands with those of other phosphines, halogenophosphines and phosphites was made on the basis of a spectroscopic investigation of the carbonyl stretching frequencies of the complexes [Mo(CO)5{PPhm(CFCF2)n}] (n + m = 3).