The PGA Research Group

Wangchuk Rabten

The present global energy consumption is expected to rise at least two-fold by 2050 due to increase in population and economic growth.1 In the short run, this could perhaps be met by using fossil fuels such as coal, natural gas and oil. However, the reserve of fossil fuels are continuously diminishing2 and their combustion continues to be a major cause of environmental pollution and climate change. Hence, the need for the development of an alternative to fossil fuels is rapidly becoming our society’s greatest challenge, both in terms of science and technology.
In Nature, the sun provides an enormous amount of energy. Plants, algae and cyanobacteria trap a small part of this solar energy and convert it into chemical energy by means of photosynthesis. This process has been refined under billion years of evolution and scientists are now investigating artificial photosynthesis as an alternative to current technologies. Success will bring humans one-step closer to generating an environmentally friendly and carbon-neutral fuel.
My research is focused on the development of versatile catalysts (WOCs) that oxidize water into molecular oxygen at neutral pH, driven by the mild one-electron oxidant [Ru(bpy)3]3+, using natural photosynthesis as a model. Here, the splitting of H2O to O2 and H2, or related fuels, constitutes an excellent example of solar to fuel conversion schemes.

(1) Barber, J.; Tran, P. D. From natural to artificial photosynthesis, 2013; Vol. 10.
(2) Simmons, M. R. Twilight in the Desert; John Wiley & Sons, Inc.: Hoboken, New Jersey 2005.

Part of my research project deals with the development of N,P-iridium catalyst and its application in asymmetric hydrogenations of di- and trisubstituted cycloalkenes. Other parts of the project focus on the synthesis of chiral cyclic allylsilanes and further chemical transformation employing Hosomi-Sakurai allylations.

Currently I am working on asymmetric hydrogenation of vinyl fluoride. We have previously reported on the introduction of stereogenic centers on the carbon-containing fluorine atom via asymmetric hydrogenation.1 Under the hydrogenation condition, we found out that defluorination was one of the major issues of the system and as well as the reaction was carried out at the higher pressure of hydrogen. Thus, the present project focus on the development of the robust catalyst that could avoid the above-mentioned issue and handle the reaction under very low hydrogen pressure and also focus on the expansion of the substrates scope.

1(a) M. Engman, J. S. Diesen, A. Paptchikhine, P. G. Andersson, J. Am. Chem. Soc. 2007, 129, 4536-4537. (b) P. Kaukoranta, M. Engman, C. Hedberg, J. Bergquist, P. G. Andersson, Adv. Synth. Catal. 2008, 350, 1168-1176.