Haloalkyl complexes of the transition metals: VIII. The synthesis and properties of [CpW(CO) 3CH 2X] (X  OCH 3, Cl, Br, I) and their reactivity with neutral donor ligands

Abstract

The complexes [CpW(CO) 3CH 2X] (Cp  ν 5-C 5H 5, X  Cl, Br, I) have been prepared. Their reactions with a series of tertiary phosphines, amines, SMe 2 and AsPh 3 in THF, CH 3CN, CH 2Cl 2 and MeOH have been investigated. Two types of cationic products, namely the ylide complexes [CpW(CO) 3CH 2L] + and the disubstituted complexes [CpWL 2(CO)2] + were obtained, the outcome depending on the halide (X), the p K a, cone angle and concentration of the ligand (L), and the solvent used. These variables were also found to have significant influence on the reaction rates. The reactions of [CpW(CO) 3CH 2X] with L were found to be significantly slower than those of the analogous [CpFe(CO) 2CH 2X] complexes with the same ligands.