فهرست نشریات علمی دسترسی آزاد ایران

AbstractThe kinetics of the ligand exchange reaction between the tetraaza macrocycle, N42HClO4 (where N42HClO4 is 5,7,7,12,14,14-Hexaniethyl-1,4,8,11-tetraazacyclo tetradeca-4,11-diene dihydrogen perchlorate) and CuLX complexes, where L is N-(2-carboxy phenyl)salicyliden imine a tridentate Schiff base dianionic ligand and X is a neutral monodentate ligand have been studied by visible spectrophotometry in dimethylformamide, DMF, solvent at 25 ± 0.2°C and an ionic strength of 0.1 M NaClO4. The kinetics of the ligand exchange reaction were studied under pseudo-first-order with [N42HClO4] >> [CuLX] by measuring the absorbance changes at 700 nm, corresponding to the maximum difference in molar absorptivity between reactants and products. Under these conditions, the reaction was found to proceed via a two-step process (biphasic reaction). Therefore, two rate constants kobs(1) and kobs(2), were obtained. The first step was rapid and dependent on the macrocycle concentration, [N42HClO4], whereas the second step was not significantly affected by [N42HClO4] and is the determining step. A mechanism consistent with these results is proposed.