Copper(II) complexes with (E)–4–(2–(pyridin–2–ylmethylene)hydrazinyl)quinazoline and non–steroidal anti–inflammatory drugs: Structure and biological evaluation

Abstract

Four novel Cu(II) mixed−ligands complexes containing the quinazoline (E)−4−(2−((pyridin−2−yl)methylene)hydrazinyl)quinazoline (HL) or its methoxylated derivative (HL1) and a non−steroidal anti−inflammatory drug (mefenamic acid, flufenamic acid, diflunisal or diclofenac) as ligands were synthesized and characterized with single−crystal X−ray crystallography. In these complexes, the quinazolines are as tridentate or bridging tetradentate ligands. The studied biological properties of the complexes included the interaction with calf−thymus DNA, the ability to cleave supercoiled circular pBR322 plasmid DNA in the absence or presence of various irradiation wavelengths, the ability to reduce H2O2 or to scavenge free radicals such as 1,1−diphenyl−picrylhydrazyl and 2,2'−azinobis−(3−ethylbenzothiazoline−6−sulfonic acid), and the affinity for bovine serum albumin. The compounds can bind tightly to calf−thymus DNA via intercalation, and most of them induce notable (photo)cleavage of plasmid DNA. They can also bind tightly and reversibly to the albumin and exhibit moderate−to−significant activity towards 2,2'−azinobis−(3−ethylbenzothiazoline−6−sulfonic acid) radicals and H2O2.