Table of Contents
Journal of Theoretical Chemistry
Volume 2013 (2013), Article ID 342783, 9 pages
Research Article

Metal Ion Selectivity of Kojate Complexes: A Theoretical Study

Department of Chemistry, University of Delhi, Delhi 110 007, India

Received 23 March 2013; Accepted 9 June 2013

Academic Editors: A. Kokalj, G. Pacchioni, and J. R. Sabin

Copyright © 2013 Sarita Singh et al. This 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.


Density functional calculations have been performed on four-coordinate kojate complexes of selected divalent metal ions in order to determine the affinity of the metal ions for the kojate ion. The complexation reactions are characterized by high energies, showing that they are highly exothermic. It is found that Ni(II) exhibits the highest affinity for the kojate ion, and this is attributed to the largest amount of charge transfer from the ligand to the metal ion. The Ni(II) complex has distorted square planar structure. The HOMOs and LUMOs of the complexes are also discussed. All complexes display a strong band at ~1500 cm−1 corresponding to the stretching frequency of the weakened carbonyl bond. Comparison of the complexation energies for the two steps shows that most of the complexation energy is realized in the first step. The energy released in the second step is about one-third that of the first step.