Formation and stability of Co(II), Ni(II), Cu(II) and Zn(II) complexes of pyridoxal semicarbazone and pyridoxal thiosemicarbazone in solution Aduri Saritha1, Reddy Ch. Venkata Ramana2,*, Sireesha B.1 1Department of Chemistry, Nizam College, OU, Hyderabad-500 001, India 2Department of Chemistry, Jawaharlal Nehru Technological University Hyderabad, Hyderabad-500 085, India *Corresponding Author E-mail: vrr9@yahoo.com
Online published on 9 March, 2017. Abstract The formation and stability of Pyridoxal semicarbazone (PLSC) and Pyridoxal thiosemicarbazone (PLTSC) Schiff base ligand (L) complexes of Co(II), Ni(II), Cu(II) and Zn(II) have been investigated by Irving-Rossotti pH-metric titration technique, at 30 ± 1ºC and an ionic strength of 0.1M KNO3 in 70% v/v DMF-H2O medium. The acid dissociation constants (pKa) of the ligands and the stability constants of the metal complexes formed in solution were determined. The results indicate the formation of 1:1(ML) and 1:2(ML2) complexes in solution. The order of stability of the metal complexes with respect to the metal ions follows the Irwing -william's natural order, Co(II) < Ni(II) < Cu(II) > Zn(II). Top Keywords Schiff base, transition metals, pH metry, stability constants. Top |