👤 Shaik Mustafa

Pyridyl–tetrazole ligands 2-(5-(pyridin-2-yl)-1H-tetrazol-1-yl)acetamide (L1), 2-(5-(pyridin-2-yl)-2H-tetrazol-2-yl)acetamide (L2), 2-(5-(pyridin-2-yl)-1H-tetrazol-1-yl)acetohydrazide (L3) and 2-(5-(pyridin-2-yl)-2H-tetrazol-2-yl)acetohydrazide (L4) have been prepared and coordinated with CuCl2·2H2O to furnish the corresponding complexes [Cu(L1) 2 ]–[Cu(L4) 2 ]. EPR spectra of the complexes are characteristic of square planar geometries, with nuclear hyperfine spin 3/2. DNA-binding studies using UV–Vis absorption spectroscopy, viscosity and thermal denature studies revealed that all of these complexes are avid binders of calf thymus DNA. The antioxidant properties of the free ligands and the Cu(II) complexes were investigated using the p-nitrosodimethyl aniline hydroxyl radical scavenging method, and [Cu(L4) 2 ] was found to show the highest activity. Show less

Abstract2‐(1H‐Tetrazol‐5‐yl)pyridine (L) has been reacted separately with Me2NCH2CH2Cl⋅HCl and ClCH2CH2OH to yield two regioisomers in each case,N,N‐dimethyl‐2‐[5‐(pyridin‐2‐yl)‐1H‐tetrazol‐1‐yl]ethanamine (L1)/N,N‐dimethyl‐2‐[5‐(pyridin‐2‐yl)‐2H‐tetrazol‐2‐yl]ethanamine (L2) and 2‐[5‐(pyridin‐2‐yl)‐1H‐tetrazol‐1‐yl]ethanol (L3)/2‐[5‐(pyridin‐2‐yl)‐2H‐tetrazol‐2‐yl]ethanol (L4), respectively. These ligands,L1–L4, have been coordinated with CuCl2⋅H2O in 1 : 1 composition to furnish the corresponding complexes1–4. EPR Spectra of Cu complexes1and3were characteristic of square planar geometry, with nuclear hyperfine spin 3/2. Single X‐ray crystallographic studies of3revealed that the Cu center has a square planar structure. DNA binding studies were carried out by UV/VIS absorption; viscosity and thermal denaturation studies revealed that each of these complexes are avid binders of calf thymus DNA. Investigation of nucleolytic cleavage activities of the complexes was carried out on double‐stranded pBR322 circular plasmid DNA by using a gel electrophoresis experiment under various conditions, where cleavage of DNA takes place by oxidative free‐radical mechanism (OH⋅).In vitroanticancer activities of the complexes against MCF‐7 (human breast adenocarcinoma) cells revealed that the complexes inhibit the growth of cancer cells. TheIC50values of the complexes showed that Cu complexes exhibit comparable cytotoxic activities compared to the standard drug cisplatin. Show less