Synthesis, Characterization, and Cytotoxic Activities of a Schiff Base Ligand and Its Binuclear Copper(II) and Manganese(III) Complexes

Abstract

A novel symmetrical N2O2 type Schiff base (1) and its copper (II) (2) and manganese (III) (3) complexes were synthesized and characterized by spectroscopic, analytical, and magnetic susceptibility studies. Spectroscopic and magnetic susceptibility studies suggested that copper and manganese ions are in 2+ and 3+ states and their complexes have a binuclear double stranded helical structure in the form of 2:2 (metal to ligand) stoichiometry. Cytotoxic effects of the ligand and its metal complexes against MCF-7 (human breast cancer cell line), DLD-1 (human colorectal cancer cell line), ECC-1 (human endometrium cancer cell line), DU-145 (human prostate cancer line), MDA-MB231 (human breast cancer cell line), PC-3 (human prostate cancer line) and HEK293 (normal cells) were evaluated by determining their cellular viability using the colorimetric 3-(4,5dimethylthiazole-2-yl)-2,5-biphenyl tetrazolium bromide (MTT) assay. It has been found that cytotoxicity of the ligand was significantly enhanced towards cancer cells and declined towards normal HEK293 cells by metal chelation. Copper complex yielded better results in comparison with manganese complex. Particularly, copper complex showed a selective cytotoxicity, harming the cancerous cell lines while not impairing the normal cells, which is considered as the key to the future of cytotoxic therapy.

Novel Nickel (II), Copper (II) and Cobalt (II) Complexes of Schiff Bases A, D and E: Preparation, Identification, Analytical and Electrochemical Survey

“…in degree Celsius were checked with a capillary devices and were recorded on electro thermal VeeGo Digital model VMP-D.Jenway. All the compounds were routinely characterized and checked by FT-IR, 1 H NMR and 13 C-NMR, CHN, electronic spectroscopies and CV. Infrared spectra were measured in KBr disc (400-4000 cm -1 ) in Japan (a Shimadzu model 8400S FTIR spectrometer).…”

“…Infrared spectra were measured in KBr disc (400-4000 cm -1 ) in Japan (a Shimadzu model 8400S FTIR spectrometer). 1 HNMR and 13…”

“…There are different ways are used to calculate stability constant while the determination of the concentration of complexes are preferred when the complex is colored. 41 α =A m -A s /A m (1) Where α = degree of analysis, 42, 43 As = Absorbance of the same quantities of Ligand : Metal, Am= Absorbance of excess quantity of ligand with constant volume of metal L : M (1:1), see equation (2). Where C= Concentration of the ligand when C ligand = C metal.…”

“…Schiff base was invented by Hugo-Schiff which is named after line, 1 They are defining as condensation results of the reaction between aldehyde or ketone with primary amine and theses are including azomethine functional group (HC=N), which is reversible reaction and commonly carry out in acid or base medium, or with high temperature. 2 Synthesis of Schiff base depends on the dehydration of carbinolamine which considers as the rate determination step of the reaction and this is the reason of using acid as catalyst.…”

“…23 The wave form of reversible couple is complex due to the united effects of polarization and diffusion, this variation mainly result from this effect, of analyte diffusion rates, the wave form is influenced too by the electron transfer rate. 24 Because of broad area of applications of the metal complexes of Schiff bases, we now report this present investigation which deals with new octahedral Cobalt(II), Copper(II) and Nickel(II) complexes with Schiff bases A, D and E. We have synthesized, characterized these compounds using CHN, FT-IR, electronic spectroscopy, 1 H and 13 C NMR and studied analytical and electrochemical features, which were achieved by CV technique of Schiff base ligands as co-ligands for their coordination behavior in their complexes using various techniques.…”