Copper (II) complexes of a hydrazone ligand bearing quinoline moiety: Preparation, spectral, antitumor, and molecular docking studies

Abstract

Reaction of 1‐(4‐methylquinoline‐2‐yl)hydrazine with Alloxan yielded a new hydrazone ligand (AlloxHQ). Binary copper (II) AlloxHQ complexes have been successfully prepared utilizing different copper (II) salts (chloride, bromide, sulfate, and acetate). Moreover, ternary complexes have been prepared by using secondary ligands; 1,10‐phenanthroline and oxine. The structures of AlloxHQ and Cu (II)‐AlloxHQ complexes have been investigated with the aid of elemental analysis, nuclear magnetic resonance, infrared, electronic, mass, and electron spin resonance spectra, thermal analysis in addition to measurements of molar conductivity and magnetic susceptibility. Mono‐, bi‐, and tri‐nuclear complexes were obtained, reflecting that the coordinating manner of AlloxHQ is extremely influenced by both the nature of the counter anion and the pH of the medium. AlloxHQ acts as a tri‐, bi‐, or penta‐dentate ligand with different modes of bonding. AlloxHQ and its copper (II) complexes exhibited antitumor activity towards Ehrlich Ascites Carcinoma and coordination with copper improved the antitumor activity. The biological activity was confirmed by molecular docking study to investigate how the title compounds bind to the CDK‐5 inhibitor‐crystal structure of inhibitor EFP with CDK‐2 (PDB ID: 3IG7).