Fabrication, spectroscopic characterization, calf thymus DNA binding investigation, antioxidant and anticancer activities of some antibiotic azomethine Cu(II), Pd(II), Zn(II) and Cr(III) complexes

Abstract

This study was conducted to prepare novel azomethine chelates of Cu(II), Pd(II), Zn(II) and Cr(III) with tridentate dianionic azomethine OVAP ligand 2-[(2-hydroxyphenylimino)methyl]-6-methoxyphenol. The prepared compounds were characterized using elemental analyses and spectral, conductivity, magnetic and thermal measurements. The spectroscopic data suggest that the parent azomethine ligand binds to the investigated metal ions through both deprotonated phenol oxygen and azomethine nitrogen atoms, and adopts distorted octahedral geometry in the case of Cr(III) and Cu(II) ions while tetrahedral and square planar geometries for Zn(II) and Pd(II) ions, respectively. In order to confirm the molecular geometry of the investigated azomethine chelator and its complexes, theoretical density functional theory calculations were employed. Correlation between experimental observations and theoretical calculations of geometry optimization results are in a good agreement. Absorption titration was used to explore the interaction of the investigated azomethine metal chelates with calf thymus DNA, and the binding constant as well as Gibbs free energy were evaluated. Viscosity measurements and gel electrophoresis studies suggest intercalative and replacement binding modes of the azomethine metal chelates with calf thymus DNA. Additionally, the antimicrobial activity of the complexes was screened against some pathogenic bacteria and fungi. This biological study shows that the complexes exhibit a marked inhibitory effect compared to the corresponding ligand and standard drugs.Furthermore, the effect of the novel compounds as antioxidants was determined by reduction of 1,1-diphenyl-2-picrylhydrazyl and compared with that of vitamin C. Finally, in vitro cell proliferation via MTT assay was investigated against colon carcinoma cells (HCT-116), hepatic cellular carcinoma cells (HepG-2(and breast carcinoma cells (MCF-7) to calculate the cytotoxicity of the prepared compounds. Cell proliferation is inhibited for all compounds and in a dose-dependent manner in the sequence of OVAPPd > OVAPCu > OVAPZn > OVAPCr > OVAP azomethine ligand.

Novel azomethine Pd (II)‐ and VO (II)‐based metallo‐pharmaceuticals as anticancer, antimicrobial, and antioxidant agents: Design, structural inspection, DFT investigation, and DNA interaction

“…Moreover, polydentate imine chelators have been found to have plenty of advantages inside their capacity of coordination and biological activity and in the extracting of metals in analytical chemistry . It was reported that minor modifications in the ligand structure having hard/soft atoms such as oxygen, sulfur, and nitrogen have affected the activity of compounds . Cancer is the third leading cause of human mortality worldwide.…”

“…The resulting yellow solid was filtered, washed three times with ethanol, and dried under vacuum in the presence of dehydrated CaCl 2 . SCHEME 1 Synthetic strategy for the preparation of the investigated NBA ligand and its Pd (II) and VO (II) complexes 13 C NMR (δ, ppm), in DMSO-d 6 : 192, 170, 139, 138, 137, 136, 133, 132, 131, 130, 121, 120, 115, and 114.…”

“…Also, it displays multiplet signals at 8.48 to 6.51 ppm for aromatic of 8-CH protons. 13 C NMR presents the peaks at different values of δ, as follows: azomethine group (CH═N) at δ 170.00 ppm, the carboxylic group at 192 ppm, and aromatic carbon atoms in the area 114.00 to 139.00 ppm (cf. Figure S1).…”

“…[12] It was reported that minor modifications in the ligand structure having hard/soft atoms such as oxygen, sulfur, and nitrogen have affected the activity of compounds. [13][14][15] Cancer is the third leading cause of human mortality worldwide. Thus, many investigations on coordination of imine ligands with transition metal ion have been reported and showed that these complexes possess anticancer activity.…”

Evaluation of newly synthesized derivatives of bis(hydrazine‐1‐carbothioamide) and their metal complexes synthesized in bulk and nano size as potent anticancer agents

“…All these results are in accordance with the conductance data. From the FT‐IR spectrum of each complex, the bands that appeared at 505–555 and 449–495 cm –1 in all complexes have been assigned to ʋ(M‐S) and ʋ(M‐N), respectively . These two frequencies support the formation of M–N and M–S bonds.…”