Preparation of some new schiff base ligands and their characterizations by spectroscopic methods

Ill SUMMARY Syntheses of Schiff bases and their metal complexes have received growing interest due to a variety reasons. They play a crucial role in some biological processes. They are formed as intermediates in many enzymatic reactions. They are used as biological models in understanding the structure of biomolecules and biological processes. They are also used as starting materials for the production of pharmaceuticals, dyestuffs, plastics, insecticides and fungicides in industry. There is extensive literature on their use as catalysts in some important industrial processes. In this study, five Schiff bases have been synthesized by the condensation of 4.4"-diaminodiphenylmethane (4,4"-methylenedianilinc) with acetylacetone, 3- chloroacetylacetone. salicylaldehyde. benzaldehyde and m-tolualdehyde. In addition, a macrocyclic Schiff base has been synthesized by the reaction of m-phenylene with 3-oxa-l,5- bis(o-carboxaldehydephenoxy)pentane. These new six ligands have been characterized by IR, 'H-NMR, UV-vis spectroscopy and elemental analysis. Even though some metal complexes of these ligands have been synthesized, their structures have not been determined yet.