Synthesis, Spectroscopic Analysis, Antimicrobial and Antioxidant Screening of Some Organyltellurium(IV) Complexes

Abstract

In present study, six new organyltellurium(IV) Schiff base complexes with the formula RTeCl2·H4AP (1a-c) and R2TeCl·H4AP (1d-f), where R= 4-methoxyphenyl, 4-hydroxyphenyl and 3-methyl-4-hydroxyphenyl, ligand H4AP = 1-(((4-hydroxyphenyl)imino)methyl)-naphthalen-2-ol obtained from the condensation of 2-hydroxy-1-naphthaldehyde with 4-aminophenol were synthesized and characterized by elemental analysis, molar conductance, mass spectrometry, FT-IR, UV-visible, 1H NMR, 13C NMR spectroscopy. Correlation of all spectroscopic data suggested that Schiff base ligand (H4AP) acts as bidentate (ON) ligand coordinated to tellurium ion via naphthalene ring-O and imine-N with the distorted square pyramidal geometry around the tellurium ion. DFT based calculations were done for the ligand and its metal complexes to confirm the geometry of complexes. Chemical quantum parameters were determined for the ligand and the complexes. The antioxidant activity of the Schiff base and their organyltellurium(IV) complexes were assessed on the basis of radical scavenging effect of DPPH. The free Schiff base and its complexes were screened for the in vitro antifungal and antibacterial activity. The results show that the organyltellurium(IV) complexes were more active than the Schiff base. The molecular docking simulations carried out to study the probable binding modes of the ligand with various proteins receptors such as C. albicans and E. coli.