Oxovanadium(IV) complexes with unsymmetrical macrocyclic ligands derived from <i>o</i>-bromoaniline, <i>α </i>-or <i>β</i>-diketones and primary diamines

Abstract

A new series of N₄-donor unsymmetrical oxovanadium (IV) complexes of type [VO(mac)]SO₄ (mac = macrocyclic ligands derived from <i>o</i>-bromoaniline, <i>α </i>-or <i>β</i>-diketones and aliphatic diamines <i>e.g. </i>ethylenediamine or 1 ,3-propylenediamine ) have been prepared by template synthesis. Tentative structures of the complexes have been proposed on the basis of elemental analysis, electrical conductance, magnetic moment and spectral (IR.

electronic and EPR) data. The X-band EPR spectra of all the complexes have been recorded at room temperature and at liquid N₂ temperature. The room temperature EPR spectra do not show anisotropy because of rapid tumbling of molecules in solution. The spectral studies support square-pyramidal geometry for the vanadium(IV) complexes.