Chemists at the University of Amsterdam (UvA) are one step closer to a bio-inspired rational design for selective homogeneous catalysts. The study was recently published as a back-cover article in Angewandte Chemie International Edition, the world's leading chemistry journal.
Chemists at the University of Amsterdam (UvA) are one step closer to a bio-inspired rational design for selective homogeneous catalysts. They made a so-called ‘Rhodium-bisphosphine complex’ with a binding site for carboxylates and phosphates. Control of selectivity in reactions is crucial for the development of sustainable synthetic routes for the fine chemicals industry. The study was recently published as a back-cover article in Angewandte Chemie International Edition, the world's leading chemistry journal.
Homogeneous catalysis using transition metals makes new selective synthesis routes possible. The activity and selectivity of the catalyst is determined by the metal and the ligand, usually an organic molecule where many possibilities for variation exist. The search for a selective catalyst often implies the search for an appropriate ligand. Nature uses a much wider range of tools to control selectivity. Thus, the substrate (the substance), which needs to be converted into an enzyme, is often correctly positioned by hydrogen bonding interactions between the substrate and functional groups in the cavity of the enzyme where the substrate is converted.
Pawel Dydio, a trainee research assistant in the research group of UvA Professor Joost Reek, made a Rhodium-bisphosphine complex with a binding site for carboxylates and phosphates. The rhodium complex is an active catalyst for the hydroformylation reaction, the chemical conversion of olefins into aldehydes. Here is an aldehyde was introduced into a C-C double bond, which usually leads to two different products. Dydio discovered that the reaction is highly selective for alkene substrates with additional carboxylate or phosphate groups which position the substrate in the correct fashion in relation to the metal.
The uniqueness of the new system developed by Dydio and his colleagues is that the selectivity of the catalyst is determined by the positioning of the substrate. Calculations show how this leads to higher selectivity and activity. The more detailed the substrate between the metal and the binding site fit, the higher the selectivity. This result is a bio-inspired rational design of selective homogeneous catalysts one step closer. These type of catalysts and principles should in future be used in the synthesis of compounds for the fine chemical industry and for medicines.
Dydio, P., Dzik, W. I., Lutz, M., de Bruin, B. and Reek, J. N. H. (2011), ‘Remote Supramolecular Control of Catalyst Selectivity in the Hydroformylation of Alkenes’, in: Angewandte Chemie International Edition, Volume 50, Issue 2, January 2011.