Synthesis, Spectroscopic, Biological and DFT Studies of 2,4,6-Tris(4-Carboxyphenylimino-41-Formylphenoxy)-1,3,5-Triazine and its Trinuclear Dy(III) and Er(III) Salen Capped Complexes

Abstract

Uchechukwu S. Oruma, Pius O. Ukoha, Collins U. Ibeji, Lawrence N. Obasi, Obinna C. Okpareke, Ebubechukwu N. Dim, Klaus Jurkschat and Ponnadurai Ramasami

A tripodal Schiff base ligand, 2,4,6-tris(4-carboxyphenylimino-4¹-formylphenoxy)-1,3,5-triazine (H₃CT) and its trinuclear Dy(III) and Er(III) complexes were synthesized. Characterization of these compounds was done via UV-Visible, IR, ¹H, and ¹³C NMR spectroscopies, elemental analysis, and molar conductivity measurements. The spectral studies indicate that the ligand is hexadentate and coordinates to Dy/Er(III) ions through the oxygen atoms of the carboxylic group. The trinuclear complexes were characterized as being bridged by a carboxylic group to the Dy(III) and Er(III) salen centers and display a coordination number of six. Biological studies revealed that the Dy(III) complex showed the highest activity against tested microorganisms and also gave the highest percentage parasitemia inhibition (84.0 %) relative to Artesunate (87.2 %). DFT calculations were carried out to enhance understanding of H₃CT at the molecular level based on  (B3LYP)/6-31+G(d,p). The molecular docking results revealed the binding mode of H₃CT complexed with Staphylococcus aureus.