Design, Synthesis, Characterization and Spectral Properties of para-Substituted Diimine Based Ligands for Catalytic Water Oxidation

Abstract

The increasing global energy demand requires alternative sources to fossil fuels. Artificial Photosynthesis is among the most promising alternative for generation of such kind of fuels. Although the process is different from the natural photosynthetic process, the basic principles are the same, i.e. to convert solar energy into chemical energy. By achieving this, energy can be stored in bonds, which at a later stage can be released upon combustion. The water oxidation is bottleneck of artificial photosynthesis. Therefore, the aim of this research to develop catalysts for water oxidation which are stable at the working condition and having a great TONs and TOF. The molecular catalysts are comprised of ligands which have a great influence on the catalyst structure and activity. These ligands are often based on diimine or other nitrogen-containing aromatic compounds. This thesis describes the development of diimine ligands with different substituents which will help to compare the reactivity as well as redox potential of complexes for water oxidation. According to recent literature report electron withdrawing groups assisting increase the redox potential while electron donating groups decrease the same. Therefore, in this thesis we prepared diimine ligands with substituents like Methoxy, Bromo, Chloro and Methyl which will help us to determine the efficiency and stability of the metal complexes associated with these ligand systems aiming for the purpose of water oxidation study in details