Synthesis of Schiff bases derived from 2-hydroxy-1- naphth- aldehyde and their tin(II) complexes for antimicribial and antioxidant activities

The current studies were designed to prepare tin(II) complexes of various Schiff base derivatives of 2-hydroxy-1-naphthaldehyde (HN) with L-histidine and sulfamethazine have been prepared and characterized by different physiochemical studies such as elemental analysis, atomic absorption, UV-Vis spectra, FTIR spectra, 1 H–NMR, 13 C-NMR and conductance studies. Antimicrobial and antioxidant activities were also calculated. Antibacterial activity was evaluated by the agar-well diffusion method. Two Gram-negative ( Klebsiella pneumoniae and Escherichia coli ) and three Gram-positive ( Staphylococcus aureus , Staphylococcus epidermidis and Bacillus subtilis ) bacterial strains were used. Antifungal activity was resolute against three fungal strains (Aspergillus niger , Aspergillus flavus and Alternaria solani ) by using the agar tube dilution method. The antioxidant activity of ligands and their complexes was measured on the basis of the radical scavenging effect of 1,1-diphenyl-2-picryl-hydrazyl (DPPH)-free radical activity. Ligand HNSM exhibited excellent activities as antibacterial activity (22 mm), antifungal activity (55%) and antioxidant activity (119 ppm). KEY WORDS : Schiff base, 2-Hydroxy-1-naphthaldehyde, L-Histidine and sulfamethazine, Tin(II) complexes, Antimicrobial activities, Antioxidant activities Bull. Chem. Soc. Ethiop. 2017 , 31(3), 445-456.  DOI: http://dx.doi.org/10.4314/bcse.v31i3.8