Synthesis, characterization and antimicrobial studies of Mn(II) complex with N-salicyl-O-hydroxyphenyleneiminato schiff base ligand

Abstract

The complex of Mn(II) with schiff base derived from 2-aminophenol and 2-hydroxybenzaldehyde has been synthesised and characterized by molar conductance, elemental analysis, FT-IR, solubility test and potentiometric studies. The elemental analysis data suggested the stoichiometry to be 1:1 [M:L]. Solubility test carried out in some common solvents showed that it is soluble in methanol, DMSO, acetone and diethylether but insoluble in benzene and ether, while in toluene is slightly soluble and these suggested the polar nature of the complex. The molar conductance measurement of the complex is 2.5 Ω^-1 cm²  mol^-1 which is very low suggesting that the complex is non-electrolyte. Evidence from Infrared spectral study indicated a strong band in the spectra of free ligand occurring at 1600cm^-1 which assigned to ν_(C=N). It shifted to lower frequency region 1520cm^-1 in the complex indicating the involvement of nitrogen atom of azomethine group. The coordination of Schiff base with the metal ion as showed by the appearance of low frequency band at 430cm^-1 due to metal-oxygen ν_(M-O) vibration thus confirming participation of oxygen in the coordination. Further coordination of metal to azomethine nitrogen ν_(M-N) is confirmed by a new band at 580cm^-1. The synthesized ligand, and metal complex were screened for its antibacterial activity using gram positive (Staphylococcus aurous) and gram negative (Escherichia coli) and antifungal activity using Aspergillum niger and Candida albican as potential antimicrobials and showed moderate activity.

Keywords: Schiff base; Mn(II) complex; Antimicrobial study