Potentiometric, thermodynamics, and modeling investigates of binary and ternary Zn(II) complexes prepared from 1-H-benzimidazole-2-carboxylic acid and some biologically active ligands

Zn (II) binary and mixed ligand complexes were examined which included 1-H-bezimidazole-2-carboxylic acid (BCA), amino acid, peptides (HL), DNA, or dicarboxylic acid. The BCA stepwise stability constants were also observed in 0.1 mol.dm−3 with chosen bivalent transition metal ions. The dynamic stability of the metal ion follows the phenomenon Cu2+ > Ni2+ > Co2+ > Zn2+, which is compatible with the metal ions order of the Irving-Williams. The Zn II-BCA complex thermodynamic parameters as presentative examples of MII-BCA complex formation were derived and discussed. The Zn(BCA)L complex is formed by amines, while the Zn(BCA)L and the Zn(BCA)(LH-1) complex are formed by amides. To evaluate the relative stabilities of ternary complexes compared to their corresponding binary counterparts, a quantitative analysis was performed using the parameters Δlog10 K, log10 βStat, and log10 X.