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A Mononuclear Manganese Complex of a Tetradentate Nitrogen Ligand – Synthesis, Characterizations, and Application in the Asymmetric Epoxidation of Olefins
Author(s) -
Shen Duyi,
Miao Chengxia,
Wang Shoufeng,
Xia Chungu,
Sun Wei
Publication year - 2014
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201402663
Subject(s) - chemistry , manganese , ligand (biochemistry) , asymmetric induction , catalysis , hydrogen peroxide , enantiomeric excess , acetic acid , diamine , enantiomer , chiral ligand , crystal structure , styrene , benzimidazole , organic chemistry , polymer chemistry , combinatorial chemistry , enantioselective synthesis , medicinal chemistry , copolymer , polymer , biochemistry , receptor
A new chiral manganese complex ( C1 ) bearing a tetradentate nitrogen ligand containing chiral bipyrrolidine and benzimidazole moieties was prepared. The structure of C1 was confirmed by ESI‐MS and crystallography. This manganese complex is an active catalyst for the asymmetric epoxidation of various olefins with excellent conversion (up to 99 %) and high enantiomeric excess (up to 96 % ee ) with hydrogen peroxide as the oxidant in the presence of 2‐ethylhexanoic acid or acetic acid. Compared with previous structurally similar manganese complexes with different diamine backbones ( C2 , cyclohexanediamine; C3 , diamine from L ‐proline), C1 showed improved asymmetric induction, especially for simple olefins such as styrene derivatives and substituted chromene. The possible reasons for the improvement of the ee values are discussed in the text on the basis of the crystal structures of the manganese complexes.