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

Abstract

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 Å. There is considerable intramolecular hydrogen bonding. In [V(CH₃CO₂H)₆]Br₂ the cations are regular octahedra (mean V–O 2.114 Å) 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.