Synthesis, structural characterization, spectroscopic studies and antimicrobial activities of Schiff base ligands and their metal complexes derived from 2-hydroxy-3-methoxybenzaldehyde

Department of Chemistry, Faculty of Science, TheM. S. University of Baroda, Vadodara-390 002, Gujarat, India

E-mail: rajendrajadeja@yahoo.com

Department of Chemistry, Christ College, Rajkot-360 005, Gujarat, India

Post-Graduate Department of Physics & Electronics, University of Jammu, Jammu Tawi-180 006,

J. & K., India

Manuscript received online 05 February 2012. revised 17 February 2012, accepted 20 February 2012

We depict the synthesis of two new Schiff base ligands, formed by the condensation of 2-hydroxy-3- methoxybenzaldehyde with 2-amino-5-methylpyridine or 2-amino-5-bromopyridine. All of these ligands have been characterized on the basis of elemental analysis, IR, ¹H NMR and Mass spectral data. The molecular. geometry of 2-(5- methylpyridin-2-ylimino)methyl)-6-methoxyphenol has been determined by single crystal X-ray study. It reveals that this ligand exist in phenol-imine tautomeric form in the solid state. The reaction of these ligands with Cu^ll and Ni^II resulted in the formation of mononuclear complexes having the general composition [ML₁,NO₃].H₂O. These complexes have been characterized on the basis of elemental analysis, metal-estimation, molar conductivity, IR, UV-Visible, ESI-Mass, thermal analysis and magnetic measurements. Non-electrolytic behavior of complexes indicates the absence of counter ion. The studies indicate a square planar geometry of the metal complexes. The Schiff base ligands and their metal complexes have been tested for antimicrobial activity against Gram-positive bacteria; Staphylococcus aureus and Bacillus subtilis and Gram-negative bacteria; Escherichia coli and Pseudomonas aeruginosa.