A Study of Polarographic Characteristics and Stability Constant of [Zn(II)-antibiotics-vitamin-BX] Complexes

Charge transfer reactions between dropping mercury electrode and [Zn(II)-antibiotics- vitamin-Bx] system were studied at pH = 7.30 ± 0.01, µ = 1.0 M NaClO4 at 298 K. The antibiotics were neomycin, chlortetracycline, oxytetracycline, tetracycline, penicillin-V and penicillin-G used as primary ligands and vitamin-Bx as secondary ligand formed 1: 1: 1, 1: 1: 2 and 1: 2: 1 complexes with Zn(II). Electrode kinetics was discussed on the basis of kinetic parameters viz. transfer coefficient (α), degree of irreversibility (λ), diffusion coefficient (D) and rate constant (k). The values of α varied from 0.42 to 0.52 (0.50) confirm that ‘transition state’ behaves between reactant and product response to applied potential and it lies between dropping mercury electrode (D.M.E) and solution interface. A small variation in potential affects the rate and rate constant greatly.