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

Four novel Cu(II) mixed-ligand 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 using single-crystal X-ray crystallography. In these complexes, the quinazolines act as tridentate or bridging tetradentate ligands. The studied biological properties of these complexes included the interaction with calf-thymus DNA, the ability to cleave supercoiled circular pBR322 plasmid DNA in the absence or presence of irradiation of various wavelengths, the ability to reduce H2O2 or to scavenge free radicals such as 1,1-diphenyl-picrylhydrazyl and 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid), and the affinity for bovine serum albumin. These 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 albumin and exhibit moderate-to-significant activity towards 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) radicals and H2O2.