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Efficient Olefin Epoxidation by Robust Re 4 Cluster‐Supported Mn III Complexes with Peracids: Evidence of Simultaneous Operation of Multiple Active Oxidant Species, Mn V O, Mn IV O, and Mn III OOC(O)R
Author(s) -
Lee Sun Hwa,
Xu Li,
Park Byeong Kwon,
Mironov Yuri V.,
Kim Soo Hyun,
Song Young Ju,
Kim Cheal,
Kim Youngmee,
Kim SungJin
Publication year - 2010
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200903135
Subject(s) - olefin fiber , catalysis , reactivity (psychology) , manganese , chemistry , cluster (spacecraft) , substrate (aquarium) , rhenium , medicinal chemistry , reaction mechanism , stereochemistry , crystallography , inorganic chemistry , organic chemistry , medicine , oceanography , alternative medicine , pathology , computer science , programming language , geology
Two new tetranuclear chalcocyanide cluster complexes, [{Mn(saloph)H 2 O} 4 Re 4 Q 4 (CN) 12 ]⋅4 CH 3 OH⋅ 8 H 2 O (saloph= N , N′ ‐ o ‐phenylenebis(salicylidenaminato), Q=Se ( 1 ‐Se), Te ( 2 ‐Te)), have been synthesized by the diffusion of a methanolic solution of [PPh 4 ] 4 [Re 4 Q 4 (CN) 12 ] into a methanolic solution of [Mn(saloph)] + . The structure of 2 ‐Te has been determined by X‐ray crystallography. These rhenium cluster‐supported [Mn III (saloph)] complexes have been found to efficiently catalyze a wide range of olefin epoxidations under mild experimental conditions in the presence of meta ‐chloroperbenzoic acid ( m CPBA). Olefin epoxidation by these catalysts is proposed to involve the multiple active oxidants Mn V O, Mn IV O, and Mn III OOC(O)R. Evidence in support of this interpretation has been derived from reactivity and Hammett studies, H 2 18 O‐exchange experiments, and the use of peroxyphenylacetic acid as a mechanistic probe. Moreover, it has been observed that the participation of Mn V O, Mn IV O, and Mn III OOC(O)R can be controlled by changing the substrate concentration. This mechanism provides the greatest congruity with related oxidation reactions that employ certain Mn complexes as catalysts.