Transition metal complexes of a multidentate Schiff base ligand containing guanidine moiety: Synthesis, characterization, anti-cancer effect, and anti-microbial activity

Guanidine Schiff bases are famous for their distinctive features and medicinal benefits with potential applications for the control of bacterial infections and cancer development. The current study was performed with a prospect to the dinuclear series of Cu(II), Ni(II), Co(II), Mn(II), Fe(III), Cr(III), Bi(III), and Zn(II) complexes of new guanidine Schiff base ligand. These complexes have been arranged and examined by H-1 NMR, mass spectra, IR, UV-Vis, ESR spectra, magnetic moments, and conductance measurements, as well as, elemental and thermal analyses (DTA and TGA). The cytotoxicity, the anti-cancer effect, and the anti-microbial activity of these complexes were assessed. The IR spectral data showed that the Schiff base behaved as a neutral bidentate or monobasic bidentate ligand bonded to the metal particles through the azomethine nitrogen atom and the hydroxyl oxygen atom in protonated or deprotonated form embracing tetragonally distorted octahedral geometries. The new complexes were non-hygroscopic dissolvable in DMSO but insoluble in common natural solvents. A molar conductance, in DMF arrangement, demonstrated that the complexes were non-electrolytes. There was a variation in the cytotoxic activity of the complexes on murine spleen cells. Also, cytotoxic and apoptotic effects, indicative of the anti-cancer activity, of the twelve complexes, were noticed against the human hepatoma (HepG2) cell line. Additionally, the newly synthesized complexes showed enhanced anti-tumor and antimicrobial effects in comparison to the parent ligand and to the standard drug. (C) 2019 Elsevier B.V. All rights reserved.