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Mechanistic Investigation on Oxygen Transfer with the Manganese‐Salen Complex
Author(s) -
Bogaerts Thomas,
Wouters Sebastian,
Van Der Voort Pascal,
Van Speybroeck Veronique
Publication year - 2015
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201500584
Subject(s) - manganese , chemistry , catalysis , oxygen atom , product distribution , oxygen , metal salen complexes , ligand (biochemistry) , computational chemistry , reaction mechanism , ab initio , organometallic chemistry , ab initio quantum chemistry methods , mechanism (biology) , spin states , photochemistry , density functional theory , organic chemistry , molecule , inorganic chemistry , biochemistry , philosophy , receptor , epistemology
The best‐known application of salen complexes is the use of a chiral ligand loaded with manganese to form the Jacobsen complex. This organometallic catalyst is used in the epoxidation of unfunctionalized olefins and can achieve very high selectivities. Although this application was proposed many years ago, the mechanism of oxygen transfer remains a question until now. In this paper, the epoxidation mechanism is investigated by an ab initio kinetic modeling study. First of all a proper DFT functional is selected that yields the correct ordering of the various spin states. Our results show that the epoxidation proceeds via a radical intermediate. If we start from the radical intermediate, these results can explain the experiments with radical probes. The subtle influences in the transition state using the full Jacobsen catalyst explain the product distribution observed experimentally.