TY - JOUR
T1 - Enhanced activity of enantioselective (salen)Mn(III) epoxidation catalysts through supramolecular complexation
AU - Morris, Gregory A.
AU - Nguyen, Son Binh T.
AU - Hupp, Joseph T.
N1 - Funding Information:
This work was supported by the National Science Foundation’s Partnership in Nanotechnology initiative (NSF Grant # CHE-9811334) and by the EMSI program of the National Science Foundation and the Department of Energy (NSF Grant # CHE-9810378) at the Northwestern University Institute for Environmental Catalysis. STN is an Alfred P. Sloan Research Fellow. STN thanks the Dreyfus Foundation, the DuPont Company, the Beckman Foundation, and the Packard Foundation for additional financial support. We gratefully acknowledge Frontier Scientific, Inc. for providing samples of 4-pyridylboronic acid used in the synthesis of ligand 3 . We thank Melissa L. Merlau and Professor Michael R. Wasielewski for helpful discussions.
PY - 2001/10/1
Y1 - 2001/10/1
N2 - (Salen)Mn(III) catalysts show increased turnover numbers in the catalytic asymmetric epoxidation of conjugated olefins upon addition of bulky Lewis acids (LA) such as zinc tetraphenylporphyrin (ZnTPP). Up to 3-fold increase in total catalytic activity and at least a 20-fold increase in catalyst stability was observed with a (salen)Mn catalyst bearing pendant 5,5′-bis-pyridyl groups. This latter enhancement is primarily attributed to formation of a coordination triad, which provides steric protection for the catalyst from bimolecular decomposition. Supramolecular complex formation enhanced the catalyst's stability without compromising its enantioselectivity.
AB - (Salen)Mn(III) catalysts show increased turnover numbers in the catalytic asymmetric epoxidation of conjugated olefins upon addition of bulky Lewis acids (LA) such as zinc tetraphenylporphyrin (ZnTPP). Up to 3-fold increase in total catalytic activity and at least a 20-fold increase in catalyst stability was observed with a (salen)Mn catalyst bearing pendant 5,5′-bis-pyridyl groups. This latter enhancement is primarily attributed to formation of a coordination triad, which provides steric protection for the catalyst from bimolecular decomposition. Supramolecular complex formation enhanced the catalyst's stability without compromising its enantioselectivity.
KW - Asymmetric epoxidation
KW - Catalytic epoxidation
KW - Manganese
KW - Salen
KW - Supramolecular chemistry
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U2 - 10.1016/S1381-1169(01)00165-0
DO - 10.1016/S1381-1169(01)00165-0
M3 - Article
AN - SCOPUS:0035478897
VL - 174
SP - 15
EP - 20
JO - Journal of Molecular Catalysis A: Chemical
JF - Journal of Molecular Catalysis A: Chemical
SN - 1381-1169
IS - 1-2
ER -