Template synthesis and characterization of oxovanadium(IV) complexes with tetraaza macrocyclic ligands and their activity on potato virus X

The oxovanadium(IV) complexes (1) of the type [VO(L)]SO4 have been prepared using an in-situ method of synthesis with ligands derived from di-2-thienylethanedione with 1,2-diaminobenzene or 2,3-diaminopyridine. These parent complexes have been further reacted with beta-diketones to yield macrocyclic complexes (II) of types [VO(mac)]SO4 (where mac = macrocyclic ligands derived by condensation of amino group of parent complex with beta-diketones), wherein the VO2+ cation acts as a template. Tentative structures of these complexes have been proposed on the basis of elemental analysis, electrical conductance, magnetic moments and spectral (infrared, electronic and electron spin resonance) data. The oxovanadium(IV) complexes are five coordinated wherein the tetraaza macrocyclic ligands act as tetradentate chelating agents. All the complexes are found to inhibit the infectivity of potato virus X, when checked using the test plant Chenopodium amaranticolor.