Abstract

E. Kodanda Ramaiah, Shiva Raj. Kashi Ram and M.G. Ram Reddy

The formation constants of Cu(II) 1:1 and 1:2 binary chelates [(Cu(Il)-L] and [Cu(II)-L2] or [Cu(II)-A] and [Cu(II)-A2] and 1:1:1 phenylhydrazono ] -propionic acid (NPHP), 2-(phenylhdrazono)- propionic acid (PHP) and 2-(p-tolylhydrazono)-propionic acid (THP) and L = catechol (cat), salicylic and (SA), ethylenediamine (en), 1,10-phenenthroline (Phen), proline (Pro), hydroxyproline (Hpro), ^-Alanine (Ala) and gtycine (Gly) have been determined potentiometrically in 40% (v/v) ethanol-water medium at 30°C and 0.10 M (KNO3) ionic strength. The ligands NPHP, PHP and THP behave as primary ligands in the presence of Cat, en, Pro, Hpro, Ala and Gly while in the presence of Phen and SA, they act as secondary ligands. The overall 1:1:1 stability constants log KCuCuAL logK Cu CuAL the differences in stability constants Δ logK and the percentage of relative stabilisation [(%) R.S.] values have been evaluated and discussed in terms of the basicity of ligands, statistical aspects, electrostatic interaction, metel-iigand π- interaction, denticity, nature of donor sits and stereochemical aspects.

Constants; Ternary; Ethanol Medium

[ View HTML Full Text]