Synthesis, characterization of Lanthanum mixed ligand complexes based on benzimidazole derivative and the effect of the added ligand on the antimicrobial, and anticancer activities

Primary Schiff Base of lanthanum (III) benzimidazole complex (2) [La(L)Cl2(H2O)] has been synthesized by condensation of the major ligand 2-(1H-benzimidazol-2-ylmethyliminomethyl) phenol (HL) (1) with lanthanum (III) chloride. The mixed ligand complexes were prepared with the reaction of salicylaldehyde or furfural aldehyde as bidentate and ammonia as a monodentate ligand with the main complex (2). The ligand, the major complex, and the mixed ligand complexes 2-5 were verified by elemental analysis, molar conductivity, spectral measurements (IR, 1H,13C-NMR, UV), and thermo-gravimetric analysis. The ligand (1) behaves as a mono-negative tridentate compound. The oxygen atom of the phenolic group, the azomethine atom, and the Penta ring nitrogen atom benzimidazole was connected to lanthanum. This bonding relationship was unchanged in all of the mixed ligand lanthanum complexes.  Antimicrobial and anticancer effects were analyzed in vitro biological studies. To evaluate the in vitro antitumor activity in HEPG2 liver and HCT116 colon cancer cell lines, the effects of ligand 1 and mixed ligand complexes 2-5 were studied. Compared with ampicillin and amphotericin B, the prepared ligand and complexes showed antibacterial and antifungal activities. The ligand and complexes exerted cytotoxicity on the HCT116 cell line superior to that observed with the HEPG2 cell line.