Cobalt(II) complexes with trimethylphosphine selenide

Abstract

Spectrochemical and magnetic data are presented for cobalt(II) complexes of trimethylphosphine selenide, CoL₄(ClO₄)₂ and CoL₂X₂(X = Cl, Br, or I), and comparisons made with the trimethylphosphine oxide and sulphide analogues. The Δ value for the [CoL₄] selenide is similar to that for the corresponding sulphide, but there is a slight decrease in β. Within each of the halide series, on the other hand Δ falls as L varies from phosphine oxide to phosphine selenide, while β shows lesser variation. The metal–selenium stretching frequency has been assigned. Some comparative results for nickel and zinc complexes are included.