Design, Synthesis, Characterization and Anticancer Evaluation of Novel Mixed Complexes Derived from 2-(1H-Benzimizadol-2-yl)aniline Schiff base and 2-Mercaptobenzimidazole or 2-Aminobenzothiazole

Two Schiff base ligands ((benzimidazol-2-phenyl)iminomethyl)phenol (HL1) (1) and 2-(1-H-benzimidazol-2-yl)phenyl)imino)methyl) naphthol (HL2) (2) were synthesized via condensation of 2-(1H-benzimizadol-2-yl)aniline and respectively salicylaldehyde or naphtylaldehyde. The synthesis of mixed complexes (3)-(6) was realized by reacting ligands HL1 (1) and HL2 (2), copper salt (CuCl2.2H2O) and respectively one equivalent of 2-mercaptobenzothiazole or 2aminobenzothiazole. The ligands as well as the metal complexes have been identified with multiple spectroscopic techniques. The results data indicate that the copper is linked to ligands via deprotonated phenolic oxygen atom, nitrogen or sulphur atom of co-ligands and the coordination was realized through the azomethine group. X-ray powder diffraction analysis of complexes suggests that they posses monoclinic structure for complexes (3) and (4), while complex (5) has orthorhombic structure and rhombohedral structure for complex (6). The in vitro anticancer activities of the different complexes were evaluated and the results revealed an important cytotoxicity of complex (6) against lung human cancer A-549 and very good selectivity with 12.4 values of inhibitory concentration IC 50. The best result was described with complex (4) and present high activities on both A-549 and Caco-2 indicating good selectivity on lung human cancer A-549 and moderate selectivity on colorectal cell line Caco-2 with 10.9 and 15.7 respectively of IC 50.

Automated summary

Two Schiff base ligands were synthesized and mixed complexes were obtained by reacting with copper salt and different co-ligands. The ligands and metal complexes were identified using multiple spectroscopic techniques. X-ray powder diffraction analysis revealed different structures for the complexes. Complex (6) showed significant anticancer activity against lung cancer cell line A-549.