VISIBLE LIGHT PHOTOREDOX CATALYSIS

The focus area of our research is Visible Light Photoredox Catalysis (VLPC). The philosophy behind visible light photoredox chemistry is to develop chemical transformations using clean, green and sustainable source of energy i.e. sunlight. The tremendous growth registered in this field in last decade spans across discovering new photocatalytic reaction approaches, new substrates as well as new photocatalysts. In addition to the serendipitous revelations, there are several well-designed approaches for discovering new chemical transformations, catalysts and substrates often based on conceptual knowledge of the reaction mechanism and systematic investigation of various reaction parameters. The most common photocatalysts used in visible light photoredox chemistry are polypyridyl complexes of iridium and ruthenium. Other than iridium or ruthenium polypyridyl complexes, the organic dyes such as eosin Y, rose Bengal, methylene blue etc. have been employed as photocatalysts under irradiation by appropriate visible light. The use of metal-based photocatalysts not only defeats the very objective of developing “greenerˮ reactions under visible light catalysis, the high cost of these photocatalysts also render them unsuitable for industrial applications. Although the organic dyes are good alternate of metal-based photocatalysts, the major drawback associated with them is the narrow window of their redox potentials against metal based photocatalysts. Therefore, our group is particularly focused on developing “organao-photoredox” mediated reactions employing small organic molecules as photocatalysts.