Synthesis, characterization and chelating properties of tannin-8-hydroxy quinoline - formaldehyde polymer

Tannin obtained from Eucalyptus plant, condensed with formaldehyde and then 8-hydroxy quinoline. The so called obtained polymer designated as TFQ was used for metal chelate formation. Thus Transition metal chelates of TFQ with Zn+2, Co+2, Cu+2, Ni+2 and Mn+2 metal ions were prepared. The ligand TFQ and its all five metal chelates were characterized by nitrogen content, IR, UV-Visible spectral studies, magnetic moments and thermogravimetry. The antimicrobial activity of all the samples has also been monitored against common microbes.

Synthesis, structural, spectral and biological evaluation of metals endowed 1,2,4-triazole

Biologically active triazole Schiff base ligand 2,4-dichloro-6-[(1H-1,2,4-triazol-3-ylimino)methyl]phenol (A) has been synthesized by the condensation reaction of an equimolar amount of 1H-1,2,4-triazole-3-amine and 3,5-dichlorosalicylaldehyde and then it coordinated with salts of metals [VO(IV), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II)] in 2:1 molar ratio to derive a series of transition metal chelates (1)-(6). All the compounds were characterized by various physical, spectral, analytical techniques and elemental analysis. Spectral characterization and magnetic moment data of complexes revealed square pyramidal geometry for vanadium complex and octahedral for remaining (2)-(6) complexes. Quantum chemical calculation has been carried out to explore optimized geometry and electronic structure of the ligand. Density functional theory (DFT) with B3LYP/6-311+g(d,p) method was performed to determine vibrational bands, frontier molecular orbitals (FMOs) and natural bond analysis (NBO) of the ligand. NBO analysis showed that the ligand bears higher molecular stability because of hyper conjugate interactions. Computational study results revealed that there was a close interaction of theoretical and experimental spectroscopic data. Global reactivity descriptors calculated by the energies of FMOs, indicated ligand to be bioactive. The synthesized compounds were studied for antibacterial, antifungal, antioxidant and antiglycation activity and the results revealed that ligand has remarkable activity which considerably increased upon chelation. KEY WORDS: Triazole ligand, Transition metal chelates, Antibacterial, Antifungal, Antioxidant, Computational study Bull. Chem. Soc. Ethiop. 2020, 34(2), 335-351 DOI: https://dx.doi.org/10.4314/bcse.v34i2.11