Researchers in the field of chemistry at the University of Amsterdam (UvA) have, in collaboration with their colleagues from VU University Amsterdam (VU), developed a new method to quickly and easily select the most active catalyst to bring about a specific chemical reaction.
Researchers in the field of chemistry at the University of Amsterdam (UvA) have, in collaboration with their colleagues from VU University Amsterdam (VU), developed a new method to quickly and easily select the most active catalyst to bring about a specific chemical reaction. The relative stability of a mixture of metal complexes can be determined through the application of mass spectroscopy. The least stable complex of this mixture results in the fastest catalytic reaction. The method developed will help speed up the process of finding new suitable catalysts for the production of medicines, for example. The research results were recently published in the scientific journal ‘Nature Chemistry’.
The speed of a chemical reaction is determined by the difference in energy between the lowest-energy intermediary (e.g., the starting substance) and the transition state. This energy difference is inversely proportional to the speed of the reaction. The phenomenon can best be compared to a cyclist who wants to cross a mountain: the lower the mountain, the faster the cyclist will be on the other side. The energy difference can be reduced by either increasing the energy level of the intermediary or decreasing the energy level of the transition state. To extend the cycling analogy: the cyclist will have to either catch a bus to take him to a higher starting point or dig a tunnel through the mountain. PhD candidate Jeroen Wassenaar and Master’s student Eveline Jansen from the research group of Dr Joost Reek (UvA) based their catalyst selection model on the first option. They provoked a ‘Darwinist’ selection process within a mixture of ligands and a metal complex and measured relative energy levels using mass spectrometry. They demonstrated that the least stable intermediary is the catalyst with the most active properties (‘survival of the weakest'). By conducting experiments with a palladium catalysed reaction the authors created carbon-carbon bonds, which are of substantial interest to the pharmaceutical industry.
The theoretical substantiation of this method was presented by PhD candidate Willem-Jan van Zeist of the VU and Matthias Bickelhaupt, professor of Theoretical Chemistry at the VU. They used density functional molecular simulation methods to calculate the energy level of the catalysts. Their findings corresponded largely with the experimental results produced by the mass spectrometer. Additionally, their calculations provided insight into the process that determines these catalysts’ stability. The results produced by these researchers prove that a ‘Darwinist’ selection process can be used to identify catalysts in a mixture of ligands. The next step is to expand the method to include other reactions, so that solutions can be found more quickly for future issues in chemical research.
The research team of Prof. Ton Spek of the University of Utrecht also contributed to the research by clarifying a crystal structure of the intermediary. The research was conducted with support from the National Research School Combination - Catalysis and the Netherlands Organisation for Scientific Research (NWO).