Kinetics and Mechanism of Ligand Substitution Reaction of Tetraamine Macrocyclic Ligand with Tridentate Schiff Base in Copper(II) Complexes

The kinetics of the substitution reaction in the CuLX complexes, where L is the salicylaldehyde semicarbazone tridentate Schiff base ligand and X = NO3, Br and ClO4 with N4H2.2ClO4 macrocyclic (N4H2.2ClO4 is 5,7,7,12,14,14-Hexaniethyl-1,4,8,11-tetraazacyclo tetradeca-4,11-diene dihydrogen perchlorate) were studied spectrophotometrically in DMF solvent at 250.1 °C and an ionic strength of 0.5 M NaNO3. The rate constants for ligand exchange reactions were obtained under the pseudo-first-order by measuring the absorbance changes at 700 nm, where equal to the greatest change in molar absorptivity between reactants and products. Under these conditions, the overall process is biphasic reaction. Therefore, two rate constants kobs(1) and kobs(2) were obtained. The kobs(1), was fast and depended on N4H2.2ClO4 concentration and the kobs(2) was not significantly affected by the concentration of N4H2.2ClO4 ligand. Based on the results, a mechanism for the ligand substitution reaction is proposed.

Kinetics and Mechanism of Ligand Substitution Reaction of Tetraamine Macrocyclic Ligand with Tridentate Schiff Base in Copper(II) Complexes Keywords:

Kinetic , Macrocyclic Ligand , Cu(II) complexes , Ligand Substitution , Schiff base