Preparation, crystal structure and magnetochemistry of [NEt4][V2Cl7(thf)2]·CH2Cl2(thf = tetrahydrofuran)

Abstract

The reaction between [VCl₃(thf)₃] and [NEt₄]₂[VOCl₄] resulted in Cl^– transfer from the [VO]²⁺ reagent and the formation of anionic V^III products. In MeCN solution, the product was the known [NEt₄][VCl₄(MeCN)₂], whereas in CH₂Cl₂ solution the new complex [NEt₄][V₂Cl₇(thf)₂]·CH₂Cl₂4 was obtained. The structure of the anion of 4 consists of a face-sharing bioctahedron with three µ-Cl^– ions. The V ⋯ V distance of 3.176(2)Å precludes metal–metal bonding. Variable-temperature magnetic susceptibility (χ_m) studies on solid samples of 4 in the temperature range 5.0–300 K have been performed. The data were satisfactorily fitted to the theoretical χ_mvs. T expression for a d²–d² dinuclear complex. The fitting parameters obtained were J=–48(1) cm^–1(Ĥ=–2JS₁·S₂), g= 1.90 and a 4.1% paramagnetic impurity. The V^III ions are thus antiferromagnetically coupled.