ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

The Study of Equilibrium and Formation Constants of Some Transition Metal Complexes with Vitamin B₆ in Solution by Potentiometry

Y. C. Zhu, M. Q. Zhang, J. G. Wu, and R. W. Deng

College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, 730000, P. R. China

E-mail: rwdeng@west163.com

Abstract: The protonation constants of vitamin B-6 (pyridoxol hydrochloride) and the formation constants of its complexes with some transition metal ions M(II) (M = Cd, Co, Ni, Cu, and Zn) were determined potentiometrically at (25 ∓ 0.1)°C and I(NaCl) = 0.2 mol dm^-3. Two computer programs MINIQUAD and MIQUV were used for calculation, and the results obtained with the two programs were in good agreement. There are two complexes species MLH and ML ascertained in the binary system, and the formation constant of complex ML for metal ions, which was found to be for Cd(II) < for Co(II) < for Ni(II) < for Cu(II) > for Zn(II), has an Irving-Williams order.

Full paper in Portable Document Format: 554a229.pdf

Chemical Papers 55 (4) 229–232 (2001)