Alkyl- and aryl-fluorophosphines as ligands in transition-metal complexes with metals in positive oxidation states. Part I. Nickel(II) and cobalt(II) halide complexes of di-(t-butyl)fluorophosphine

Abstract

Di-(t-butyl)fluorophosphine forms stable complexes of the type NiX₂L₂ and CoX₂L₂(where X = Cl, Br, or I and L = Bu^t₂PF) with nickel(II) and cobalt(II) halides. The structure of these compounds, elucidated by n.m.r., i.r., and u.v. spectra as well as by magnetic measurements is trans-square planar in the case of NiX₂L₂ and tetrahedral for the complexes CoX₂L₂. For NiCl₂(Bu^t₂PF)₂ a cis-trans-equilibrium is likely to exist in solution. The low-temperature ¹⁹F n.m.r. spectrum of the latter compound is explained by the presence of different rotamers with respect to the Ni–P axis.