Antimicrobial, antioxidant, and in silco studies of divalent metal complexes of novel aminopyrimidine Schiff base chelators

Abstract

The amino-pyrimidine-based imine-chelators, 1-((pyrimidin-2-ylimino)methyl)naphthalene-2-ol(HL1), 2-(((2-hydroxynaphthalen-1-yl)methylene)amino)pyrimidine-4,6-diol(HL2) and 1-(((4,6-dimethylpyrimidin-2-yl)imino)methyl)naphthalen-2-ol(HL3) have been synthesized by facile reaction of 2‑hydroxyl-1-naphthaldehyde with 2-aminopyrimidine, 2-amino-4,6-dihydroxypyrimidine, and 2-amno-4,6-dimethypyrimidine respectively. The chelators were coordinated with Fe(II) sulfate and Cu(II) acetate to afford the corresponding complexes which were fully characterized. The Cu(II) complex exhibited superlative antimicrobial activity with an inhibitory growth zone reaching 26.5 mm outperforming both the chelators and the Fe(II) complexes. Thus Cu(II) complex has potential significance in new antibacterial drug designs and isolation. The impressive activity was due chelation which increased the lipophilic feature of the Cu(II) complex, thereby favouring its infiltration through the lipid layers of the bacterial membranes. However, compared to other samples, Fe-L2 has the best antifungal performance activity against Aspergillus niger, Aspergillus flevus, and Rhizopus stolonifer with inhibition zone of 29±1.4, 19±2.1 and 22±1 respectively. The C18H12N5O6 antioxidant result confirmed that Cu-L2 had the highest scavenging ability (99.80%) at 200 μg/mL. Interestingly, Cu-L2 exhibited the highest antioxidant actions both in vitro and in silco evaluations, hence can serve as a potential antioxidant agent. Molecular docking determinations displayed a substantial binding affinity with the drug targets suggesting that the metallic compounds could be exploited for drugs design.