Facile synthesis of complexes of vanadium(II) and the crystal and molecular structures of hexaaquavanadium(II) trifluoromethylsulphonate

Abstract The new vanadium(II) salt [V(H 2 O) 6 ](CF 3 SO 3 ) 2 was crystallised from solutions obtained by dissolving metallic vanadium in aqueous trifluoromethylsulphonic acid. The cations in this complex are regular octahedra (VO distance=2.119(1) A) and are extensively hydrogen-bonded to the anions throughout the lattice. The salt is soluble in several organic solvents and should be a useful starting material in the preparation of vanadium(II) complexes. Thus [V(ethylenediamine) 3 ](CF 3 SO 3 ) 2 has been prepared by the addition of ethylenediamine to a solution of [V(H 2 O) 6 ](CF 3 SO 3 ) 2 in ethanol. The preparation of [VCl 2 (H 2 O) 4 ], [V(H 2 O) 6 ]Br 2 and [V(H 2 O) 6 ](BF 4 ) 2 from vanadium and the appropriate aqueous acid has been confirmed.