Solution Equilibria of Ni(II), Cu(II), and Zn(II) Complexes Involving Pyridoxine and Imidazole Containing Ligands: pH Metric, Spectral, Electrochemical, and Biological Studies

Abstract

Solution equilibria and relevant stability constants for M(II)-pyridoxine (PN)(A) [M(II) = Cu(II), Ni(II), and Zn(II)], and M(II)-PN(A)-imidazole containing ligands (B) [B = imidazole (him), benzimidazole (bim), histamine (hist), and l-histidine (his)] in aqueous solution have been determined by a pH metric method at 310 K and I = 0.15 M NaClO4. The complexation model for each system has been established by the MINIQUAD-75 program. The probable binding mode in the binary and ternary species was discussed based upon the derived stability constants. The concentration distributions of various species formed in solution were evaluated. The stability of ternary complexes follows the Irving–Williams order of metal ions, which was quantitatively (Δ log K, log X, and % RS) compared with their corresponding binary complexes. In terms of the ligands (B), the stability of the complexes follows him > bim > hist > his. The molecular geometry of the complexes formed in solution between the ligands and M(II) was determined by electronic spectra at various pH intervals. The formation of complexes and their electrochemical properties were also assessed by cyclic voltammetry. The in vitro biological activity of the ternary complexes was tested against bacteria, fungi, and yeast.

Redox-active and DNA-binding coordination complexes of clotrimazole

“…S15 †) and with previous studies of metalcoordinated histidine and imidazole-derived ligands. 51,52 For all three complexes, the Zn 2+ center is electrochemically inactive within the examined potential window. The cyclic voltammogram of [Co(clotri) 2 Cl 2 ] (2) in Fig.…”

Fluorescence response of a thiazolidine carboxylic acid derivative for the selective and nanomolar detection of Zn(ii) ions: quantum chemical calculations and application in real samples

“…The ion product of water (K w ¼ [H + ][OH À ]) at 0.15 M NaClO 4 in 95% (v/v) water-methanol mixture was calculated based on the measurement of [H + ] and [OH À ] and pH in several experiments. 33 Oxygen-free nitrogen gas was bubbled through the solution before and during titrations. Multiple titrations were carried out for each system.…”

Volumetric and Viscometric Studies of Amino Acids in Vitamin B6 Aqueous Solutions at Various Temperatures

“…Usually, they are water-soluble and are based mainly on the pyridine ring as their molecular structures . An improper intake of vitamin B could affect detrimentally the metabolism of sugar, fat, and protein, and even bring about neurologic disorders and the decay of the immune function. , As is well-known, vitamin B6, a general name given to pyridoxine, pyridoxamine, pyridoxal, and their phosphorylated derivatives, , is one of the most important vitamins among all vitamin B complexes because of its wide functions in various systems of the body (immune system, nervous system, lipid metabolism, gluconeogenesis, hormone modulation, niacin formation, gene expression) . It participates in more than 100 enzymatic reactions in which the most striking function lies in its service as a cofactor for enzymes during the biosynthesis process of amino acid. , Accordingly the study on the vitamin B6 system has become an interesting subject.…”