EPR and spectroscopic studies of S-methyl-N-salicylidenehydrazinecarbothioatophenanthroline-oxovanadium(IV) as model compound for vanadium bound to nitrogen and sulfur heteroatoms

Synthesis and EPR characterization of a vanadyl complex salicylaldehyde Schiff base in methylene chloride is described. The vanadyl complex synthesized is S-methyl-N-salicylidene-hydrazinecarbothioatophenanthrolineoxovanadium(IV). The magnetic parameters for this system are determined from computer simulation of the rigid limit EPR spectrum at 77 K and analysis of the isotropic spectrum at room temperature at X-band frequency. A good correlation is found between g_∥ and A_∥ of the system studied when compared with other model compounds of vanadyl complexes in which possible combinations of four ligands may include VO(N₄), VO(N₂SO), VO-(N₂S₂), VO(NS₃), and VO(S₄). This information could be useful in characterizing non-porphyrin species of vanadium in asphaltenes.