Currently we are living our lives in an era where CO2 level in the atmosphere has become critical and our oceans are filling up with the plastic waste. So, what can we do as fundamental chemists to make our planet green again? To maintain sustainability, nature uses ‘catalysts’ to perform a chemical transformation, for example photosynthesis, that is catalyzed by enzymes. In a related fashion, homogeneous catalyst can enable challenging chemical transformations under mild conditions and at the same time advance our mechanistic understanding at the molecular level. Embracing the principles of green chemistry and recently coined circular chemistry, we are interested in the development of new homogeneous catalysts and their applications in the service of clean energy and environment.
Synthetic Organometallic Chemistry
Using bottom-up approach, we are interested in the ligand design and synthesis of new transition-metal complexes of interesting catalytic properties. Pincer type structural motifs due to their robust nature and fascinating catalytic activities are popular choices of ligands. We are interested in expanding the horizons of rich pincer chemistry from transition-metals to main-group elements such as alkali and alkaline-earth metals. Furthermore, we plan to study the reactivity of these metal-complexes to activate small molecules such as H2, H2O, N2O, CO2, HCCH, NH2R and RCH2OH.
Green Homogeneous Catalysis
We are interested in the development of green and sustainable catalytic processes for the waste-free production of useful organic compounds from feed stocks that are inexpensive or/and renewable. Our emphasis is on reactions that release or consume hydrogen gas (dehydrogenation or hydrogenation) as they have several advantages; for example, (a) (de)hydrogenation reactions are highly atom-economic and clean, (b) hydrogen gas can be produced from renewable sources for hydrogenation reactions and (c) for the dehydrogenation reactions, the produced hydrogen gas can be stored and used as a fuel. So, you can eat the cake and have it too! Moreover, we are also interested in developing efficient catalysts for the utilization of greenhouse gases such as CO2 and N2O for the synthesis of valuable chemicals.
Safe and long-term storage of hydrogen has been a longstanding hurdle in utilising hydrogen gas as a clean and renewable energy. An attractive approach has been to use hydrogen-rich organic compounds, Liquid Organic Hydrogen Carrier (LOHC). LOHCs (charged fuel carriers) are small organic compounds in liquid state at room temperature that can liberate hydrogen gas (fuel) in presence of a catalyst forming spent fuel that can be again converted back to the charged fuel carrier, thus closing the loop. The liquid state gives the advantage of utilising the already established infrastructures of delivering gasoline fuels. The current target set for 2020 for the gravimetric capacity of chemical hydrogen storage materials by the Department of Energy (DOE), USA is 5.5 wt% and that by the European Union is 5.0 wt%. (De)hydrogenation of small organic molecules bearing high hydrogen storage capacity under mild conditions can be challenging thus creating a strong need to develop efficient catalysts to tailor the purpose. We are interested in the development of efficient homogeneous catalysts for the utilization of small renewable organic compounds such as aqueous ethanol or glycerol as an LOHC.
Linear industrial production where limited resources are continuously being used to produce valuable products which upon consumption is left to degrade is root cause for several global crisis such as climate change and shortage of energy and food. One of the approaches towards sustainability is Circular Economy that is defined as “restorative and regenerative by design, and aims to keep products, components and materials at their highest utility and value at all times”. Chemistry being at the centre of industrial production plays an important role in achieving circular economy. Circular chemistry takes into account of all of the three, People, Planet and Profit (‘Triple bottom line’) for one process and advocates that a process obeying all the principles of Green chemistry is not sustainable until it is economic. At the centre of all the principles of Circular Chemistry lies utilization of waste as a resource. We are interested in developing catalytic (de)hydrogenation processes for the depolymerisation of plastic waste e.g. polyesters, polycarbonates, nylons and polyethylene to produce either the monomers or other useful organic compounds. Moreover, we are interested in converting the depolymerised monomers back to polymers using catalysts and close the loop demonstrating the circular chemistry of plastic production.