Preparation, properties, and crystal and molecular structures of trans-tetrakis(acetic acid)dichlorovanadium(II) and hexakis(acetic acid)vanadium(II) dibromide

The vanadium(II) complexes [VCl2(CH3CO2H)4] and [V(CH3CO2H)6]Br2 have been obtained from reactions between vanadium, acetic acid and HX (X = Br or Cl). Crystal structure analysis confirms that in each case acetic acid molecules are bonded by the carbonyl oxygen rather than the hydroxyl oxygen. In trans-octahedral [VCl2(CH3CO2H)4] the mean co-ordination sphere bond distances are V–O 2.125 and V–Cl 2.497 A. There is considerable intramolecular hydrogen bonding. In [V(CH3CO2H)6]Br2 the cations are regular octahedra (mean V–O 2.114 A) and they are hydrogen bonded to the anions throughout the lattice. The reactions of HX with vanadium in some other non-aqueous solvents have been investigated.