Rahul B. Mohod

The chemistry of metal complexes has fascinated and inspired the chemist all over the world. Among the chelating ligand, Schiff base have attracted the attention of the chemist due to the ease of the preparation and complexation. Schiff base complexes have remained an important and popular area of research due to their simple synthesis versatility and diverse range of applications. Schiff bases are able to stabilize many different metals in various oxidation states. In the present study the Schiff base of 1-(5-chloro-2-hydroxy-4-methylphenyl) ethanone with 4-(2-aminoethyl)phenol has been synthesized. The complexes of this Schiff base ligand have been synthesized by using Mn(II),  Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) ions under refluxed in ethanol. These compounds have been investigated by elemental analysis, infra-red, 1H nuclear magnetic resonance, diffuse reflectance spectroscopic techniques and magnetic susceptibility measurements. The free ligand and their metal complexes have been screened in vitro for their antimicrobial activity against gram-positive bacteria S. aureus, gram negative bacteria, E. coli, S. typhi and fungi P. notatum and R. oligosporus.

There has been an extensive effort all over the world to develop inorganic complexes which can withstand severe conditions of temperature, oxidation and hydrolysis. While there has been no breakthrough, considerable progress has been made in this direction. Many of these complexes show thermal stability much higher than that of the organic substrate, employed as ligands in the synthesis of metal complexes. These complexes offer academic interest and at the same time provide materials of desired and superior qualities which promise a variety of applications. The Schiff base complexes have been synthesized from 1-(5-chloro-2-hydroxyphenyl) ethanone with 1, 3-diaminopropane using Mn(II), Co(II), Cr(II), Ni(II), Cu(II), Zn(II) and Cd(II) ions and characterized by elemental, spectral and thermogravimetric analysis. The ligand acts as tetradentade molecule coordinating through deprotonated phenolic oxygen atoms and azomethine nitrogen atoms. The isolated products are colored solids and are soluble in DMF and DMSO. The thermogravimetric study indicates all the complexes are stable up to 60-700 C. All the complexes show half decomposition temperature (Table-3) and various kinetic and thermodynamics parameters have been evaluated from thermal data. The similarity in the values of kinetic parameters indicates a common decomposition reaction mode in all the complexes. The thermal activation energy of all the complexes has been calculated by Freeman-Carroll and Sharp-Wentworth methods.