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 <bold>(BCA)</bold>, 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 M-II-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 Delta log(10) K, log(10) beta Stat, and log(10) X. There was discussion about the impact of amino acid ligand (Delta R) side chains on complex creation. Delta log(10)K values prove that Ternary complexes that contain the aromatic amino acids are considerably more robust than the complexes with alkyl- and hydroxyalkyl-replaced amino acids. This observation could serve as evidence for a stacking phenomenon between the aromatic group of <bold>BCA</bold> and the bioactive ligand's aromatic side chains, suggesting an intermolecular interaction between these components. The assessment of concentration distributions of various species generated in a solution is examined concerning pH variations. The form of the M(II) complexes has indeed been geometrically optimized, and the consequence of molecular parameters confirms certain complexes ' experimental formation constants. The estimated pKa attained by docking the 1-H-benzimidazole-2-carboxylic acid <bold>(BCA)</bold> measurements are in line with the experimental values.