EFFECT OF DENATURANTS ON THE SPECIATION OF AMINO-ACID COMPLEXES COMPUTER-AUGMENTED MODELING STUDIES .5. COBALT(II), COPPER(II), AND ZINC(II) COMPLEXES OF L-ORNITHINE IN WATER-UREA MIXTURES

The speciation of Co-II, Cu-II and Zn-II complexes of L-ornithine has been studied in varying concentrations (0-36.83%, w/w) of urea solutio ns maintaining an ionic strength of 0.16 mol dm(-3) at 303 K. Titratio ns have been performed with a nide range of metal-to-ligand ratios (1 : 1.6 - 1 : 53), The primary alkalimetric data are pruned with a compu ter program SCPIID, The approximate formation constants thus obtained are refined with the computer program MINIQUAD, 75, Tile selection of best lit chemical models is based on statistical parameters and residu al analysis. The active form of the ligand is LH32+, and the metal-lig and species detected are ML+, ML2, MLH2+, ML2H+, ML2H22+ and ML2H44+. Global stability constants are evaluated using ANOVA, The trend in bet a values of. the proton-ligand and the metal-ligand complexes with til e change in the dielectric constant of the medium is attributed to til e changes in the electrostatic and nonelectrostatic forces.