A Double‐Cavity‐Containing Porphyrin Host as a Highly Stable Epoxidation Catalyst. Issue 23 (15th July 2015)

• Record Type: Journal Article
• Authors: Thomassen, Paul J.; Varghese, Shaji; Bijsterveld, Edward J. A.; Thordarson, Pall; Elemans, Johannes A. A. W.; Rowan, Alan E.; Nolte, Roeland J. M.
• Is Part Of: European journal of organic chemistry. Issue 23(2015)
• Page Start: 5246
• Page End: 5253
• Publication Date: 2015-07-15
• Subjects: Supramolecular chemistry -- Homogeneous catalysis -- Epoxidation -- Manganese -- Porphyrinoids -- Dynamic covalent chemistry; Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1002/ejoc.201500492
• Languages: English
• ISSNs: 1434-193X

Abstract

Abstract: We describe a manganese porphyrin catalyst containing two adjacent cavities, which can be used for the epoxidation of alkenes by sodium hypochlorite. A pyridine ligand bound in one of the cavities regulates the rate and selectivity of the epoxidation reaction that takes place in the adjoining cavity. Pyridine binding studies suggest that site‐to‐site communication exists between the two cavities. The alkene substrates are completely converted into epoxides by the manganese double‐cavity catalyst, but the observed epoxidation rates are low. These low rates are proposed to be a result of the energetically less favourable binding of the substrate into the cavity containing the active site due to an allosteric pinching effect. In the manganese double‐cavity arrangement the catalytically active manganese complex is efficiently protected against decomposition, leading to a catalytic system with enhanced stability. The presented work may open a new route to the construction of highly stable catalysts of which the activity and selectivity may eventually be controlled by allosteric interactions. Abstract : A highly stable double‐cavity‐containing catalytic porphyrin host has been developed. A pyridine ligand bound in one of the cavities regulates the rate and selectivity of an epoxidation reaction that takes place in the other cavity. Binding studies suggest that site‐to‐site communication exists between the two cavities.