Hindawi Publishing Corporation ISRN Inorganic Chemistry Volume 2013, Article ID 871640, 5 pages http://dx.doi.org/10.1155/2013/871640 Research Article New Insights into the Chemistry of Oxovanadium(IV) Complexes with N 4 Coordinating Ligands Ashok Kumar Yadava, 1 Hardeo Singh Yadav, 1 Uma Shanker Yadav, 2 and Devendra Pratap Rao 3 1 Department of Chemistry, North Eastern Regional Institute of Science and Technology (NERIST), Arunachal Pradesh, Nirjuli 791109, India 2 Department of Chemistry, J.P. University, Bihar, Chapra 841301, India 3 Department of Chemistry, D.A-V. College, Uttar Pradesh, Kanpur 208001, India Correspondence should be addressed to Devendra Pratap Rao; devendraprataprao@yahoo.com Received 2 September 2012; Accepted 24 September 2012 Academic Editors: W. Ding and S. B. Etcheverry Copyright © 2013 Ashok Kumar Yadava et al. is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. e syntheses of new oxovanadium(IV) complexes having general formula [VO(mac)]SO 4 have been carried out by using in situ method of preparation where vanadyl ion acts as kinetic template for the ligands derived by condensation of 2,2 � -pyridil with 1,2-diaminopropane and 1,3-diaminopropane. e complexes were characterized by elemental analyses, molar conductance, magnetic moments, and spectral (infrared, electronic, and electron spin resonance) data. All the oxovanadium(IV) complexes are �ve coordinate wherein derived ligands act as tetradentate chelating agents. 1. Introduction Vanadium is widely distributed in the biosphere and its essential role has been recognized in both plants and animals. e oxovanadium(IV) cation has been found to inhibit the plasma membrane ATPase of Neurospora crassa and Saccharomyces cerevisiae, the proton translocating ATPase of Mycobacterium phlei and Ca ++ -ATPase of red cell membranes [1–3]. It has been observed that the free vanadyl ion is oxidized to vanadate within a few minutes in aqueous solution exposed to air at neutral pH [4–6]. However, the tetravalent state appears to be stable when complexed with intracellular proteins or smaller molecules. us the complex formation of the oxovanadium(IV) cation with tetraaza lig- ands appears to be interesting, particularly in order to explore the biochemical importance of the oxovanadium(IV) cation in vitro at neutral pH [7–9].e coordination chemistry of vanadium has great interest since the discovery of vanadium in organisms such as certain ascidians and Amanita mush- rooms and as a constituent of the cofactors in vanadate- dependent haloperoxidases and vanadium nitrogenases [10, 11]. Since then, extensive studies have been carried out to explore vanadium chemistry, including the synthesis of novel complexes and their antidiabetic activities both in vitro and in vivo [12–14]. Many clinical trials of vanadium compounds have also been reported [15–17], in which vanadium salts such as VOSO 4 and NaVO 3 were administered to diabetic patients. With this view, the oxovanadium(IV) complexes of ligands derived from condensation of 2,2′-pyridil with diamines, namely, 1,2-diaminopropane and 1,3-diamin- opropane are synthesized. ese complexes are characterized by elemental analyses, molar conductance, magnetic sus- ceptibility, and spectral data. e tentative structures of these oxovanadium(IV) complexes are also ascertained on the basis of above characterization.