Preparation and electronic spectra of some oxide chloride complexes of vanadium-(IV) and -(V), with a molecular orbital treatment of the VOCl42– ion
Abstract
The preparation of some alkylammonium oxotetrachlorovanadate(IV) compounds is reported together with the syntheses of vanadium(V) oxide chloride complexes which may be formulated as containing (VOCl4)– and (VOCl5)2– ions. An MO energy-level diagram, calculated for VOCl42–, is used to make assignments of the bands in the charge-transfer spectra of both vanadium-(IV) and -(V) species. The lowest-energy charge-transfer band in these species and in the MOX5 species (M = Cr, Mo, or W) apparently arises from the excitation of an electron from non-bonding oribtals of π symmetry, localised on the halogen, to the empty or half-filled b2 orbital localised mainly on the metal.