Bis(arene)vanadium anions, a new class of organovanadium complexes: syntheses, reactivity towards carbon oxides, and electron spin resonance investigation

Abstract

Reduction of bis(arene)vanadium(0) complexes (1) with potassium in co-ordinating ether solvents gives solutions of the corresponding bis(arene)vanadate(–I) derivatives (2a; arene = benzene) and (2b; arene = mesitylene). Solvated potassium salts were isolated in yields depending on the arene ligands and the type of procedure required. The e.s.r. spectra of the reduction mixtures both in 1,2-dimethoxyethane and hexamethylphosphoramide are discussed. Solutions of K[V(C₆H₆)₂](2a) in tetrahydrofuran are quickly reoxidized by both carbon mono- and di-oxide to give the vanadium(0) complex (1a); C₁ and C₂ products are formed, the relative yields depending on the concentrations of the reactants.