Synthesis, Spectroscopic Characterization and Biological Studies of Mn(II), Cu(II), Ni(II), Co(II) and Zn(II) Complexes with New Schiff Base of 2-((Pyrazine-2-ylimino)methyl)phenol

Abstract

In the search for novel anticancer complex, transition metal complexes of Schiff base derived from 2-aminopyrazine and salicylaldehyde were successfully synthesized and characterized based on elemental analyses, spectroscopic and thermal analysis. The IR spectra showed the ligand is a tridentate chelator with O, N and N atoms. donor sites in the Zn(II), Co(II), Ni(II), and Mn(II) complexes. Contrary, it behaved a bidentate chelator in the Cu complex by O and N. Molar ratio data revealed that the ligand to metal ratio was 1:2 for Co(II) Cu(II) and Zn(II) while it was 1:1 for Mn(II) and Ni(II) complexes. The obtained complexes have the formulae [M(L)2] (where M = Co(II) and Zn(II), [M(L)Cl(2H2O)]·H2O (where M = Ni(II) and Mn(II) were octahedral geometry). The computational studies were performed by DFT calculations to compare the optimized geometries with the experimental values. The interaction of these complexes with calf thymus DNA (CT-DNA) was investigated by UV-Vis spectroscopic technique. Molecular docking studies were against three protein cancer to investigate the binding ability of the new compounds. The anticancer activity was studied with different cell lines and the IC50 of the Cu(II) complex for (HOP-62) showed a practical result. The LD50 values of Zn(II) and Co(II) complexes showed that they are non-toxic at doses up to 370 mg/kg.