Preparation of new O, S, N donor Ligands for Complexation with Transition Metals

Abstract

Metal chelation is involved in many important biological processes, where co-ordination can occur between a variety of metal ions and wide range of ligands. Generally the chelating ligands polyfunctional molecule which can encase the metal in organic sphere. Many types of ligands are known and the property of their derived metal chelates have been investigated; however there is a need for the synthesis of new ligands of special predictable properties. In the present work we have concentrated on preparation of the following ligands and their metal chelates. 1. Phenolic B-diketones: 1-(o-hydroxypheny)-3-phenyl-1, 3-propadione, its p-substituted derivatives and1-(o-hydroxypheny-4, 4-dimethyl-1, 3-pentadione were prepared by modified Baker-venkataraman rearrangement in high yield. The compounds were identified spectroscopically. The results have been published. (Annexure-I). 2. Chelates of Penolic ligands: About twenty chelates of these ligands were prepared with Cu++, Ni++, Co++, Vo++, Uo2++ salts. The UV/visible and IR-spectra were recorded. The elemental analysis and magnetic moments have also been measured. Two publications are in preparation which will include this data along with the antifungal activity of the compounds. 3. Partially thiated B-triketones: Many attempts to prepare partially thiated B-triketones failed due to the reason discussed under results and discussion. The bad smelling products also proved toxic and produced allergy to the researchers. 4. Chiral Schiff bases: Novel chiral Schiff bases were prepared from 1, 2-cycloexyldiamine, by reaction with benzoyl-acetone and benzoyl-acetyl acetone. The spectroscopy and CD of these compounds are reported. The paper is in preparation. 5. Chelates of chiral Schiff bases: Chelates with some transition metals were prepared and subjected to detailed C-D studies. The publication is submitted to Inorganica Chmica Acta (See Annexure II). 6. Phenolic pyrazoles: Phenolic pyrazoles were prepared by the reaction of phenolic B-diketones with hydrazine. The spectra and antifungal activity of these compounds have been reported. Publication in preparation. 7. Chelates of phenolic pyrazoles: Five chelates of phenolic pyrazoles have been prepared and identified.