Five-co-ordinate complexes

Abstract

The complexes VX₃,2L (X = Cl and Br; L = NMe₃, SMe₂, and C₄H₈S), VCl₃,2SEt₂, and CrCl₃,2NMe₃ have been prepared and shown to be monomeric in solutions in non-donor solvents. Structural measurements (dipole moments, i.r., visible, and u.v. spectra) indicate that the metal atoms have trans-trigonal-bipyramidal configurations. In the solid state the trimethylamine complexes also contain five-co-ordinate metal atoms, but spectral evidence shows that the sulphur complexes contain six-co-ordinate vanadium, presumably through dimerisation. Reactions of vanadium(III) chloride with higher alkyl sulphides did not give five-co-ordinate complexes; vanadium(IV) chloride was reduced by dialkyl sulphides and thiols.