Spectrophotometric study on micelle-mediated shift in kinetic and equilibrium of complex formation between Ni2+ and 2-amino-cyclopentene-1-dithiocarboxylic acid

The significant shift in kinetic and equilibrium behavior of complex format ion between Ni2+ and 2-amino-cyclo-pentene-1-dithiocarboxylic acid (ACDA) i n a solution of ionic surfactant cetyltrimethylammonium bromide (CTAB) was studied spectrophotometrically in 0.1 M NaBr medium at 30 degreesC. A model based on distributions of ligand (ACDA) and complex [Ni(ACDA)(2)] between aqueous and micellar pseudo-phase was applied to account for the shift in t he apparent formation constant and observed pseudo-first order rate constan t. Partition constants were evaluated by using a technique based on the pri ncipal component analysis method. The proposed model, states that the react ion occurs only in the aqueous phase. Apparent formation constants and the observed rate constants decreased with increasing the micelle concentration . Good agreement between experimental and calculated values indicates that, the applied model provides a good description of the micellar effects on c omplex formation between Ni2+ and ACDA. (C) 2001 Elsevier Science B.V. All rights reserved.