Event Information
Synthetic Supramolecular Allosteric Catalysts
- Abstract:
- Allosteric regulation is a well known form of control for biological molecules but is a rarity for synthetic catalysts. However, with the advent of supramolecular approaches to building multimetallic architectures, researchers now have a great deal of control over the spatial arrangement of ligand and metal building blocks so that the concept of designer catalysts, which offer more complex function by virtue of such synthetic control, may become a reality.
The design and synthesis of novel metal-based supramolecular allosteric catalysts is presented. Making use of the weak-link approach for the assembly of large, inorganic macrocycles, a new class of catalyst has been developed. This approach offers the unique advantage of allowing for the synthesis of complex, macrocyclic structures that contain coordinatively labile metal centers that can undergo further modification resulting in significant and reversible shape change. The catalysts contain structural Rh(I) centers in thioetherphosphine hemilabile pockets, and functional Cr(III) centers bound within salen-based moieties. The activity of the catalysts with respect to the asymmetric ring opening of epoxides is presented. Significant rate and selectivity changes can be affected by switching the shape of the flexible catalytic cavities. The use of shape change of a molecular catalyst, in order to control activity and selectivity, is virtually unknown outside of biology. The work presented represents a new approach to the construction of abiotic allosteric catalysts.
Reference:
1. Gianneschi, N. C.; Bertin, P. A.; Nguyen, S. T.; Mirkin, C. A.; Zakharov, L. N.; Rheingold, A. L. J. Am. Chem. Soc. 2003, 125, 10508-10509.Host: Dr. Eric Toone
Departmental Seminar