Synthesis, Characterization and Biological Activity of New Pyrimidine Schiff Base and Its Cu(II), Ni(II) Complexes

The novel Schiff base ligand (E)-2-(((2-hydroxynaphthalen-1-yl)methylene)amino)-6-methylpyrimidin-4-ol has been attained through the condensation of 2-amino-4-hydroxy-6-methylpyrimidine and 2-hydroxy-1-naphthaldehyde. Metal complexes of the Schiff base were formed by the interaction of the Schiff base and metal nitrate in an ethanol solution. The complexes were isolated, cleaned, and dried. The Schiff base appears pale yellow, whereas the Cu(II) and Ni(II) complexes exhibit a light yellow color. The synthesized compounds have been characterized by FT-IR, 1H-NMR, and UV-Vis techniques for the ligands, while FT-IR, UV-Vis, along with all reactions monitored by TLC, molar conductivity, and magnetic susceptibility measurements were employed for the corresponding complexes. The complexes are paramagnetic. The results from the molar conductivity measurements indicated that all complexes are non-electrolytes in (DMSO). An octahedral geometry is anticipated for all the complexes. The ligands are bidentate (L) through phenolic (OH) and azomethine nitrogen. The ligand and its complexes were evaluated for their antifungal and antibacterial efficacy against Aspergillus niger, Penicillium chrysogenum, Fusarium moniliforme, Aspergillus flavus, Escherichia coli, Salmonella typhi, Staphylococcus aureus, and B. subtilis. The results demonstrated that the complexes exhibited significant antifungal and antibacterial activities.