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A tale of two topological isomers: Uptuning [FeIV(O)(Me4cyclam)]2+ for olefin epoxidation.
- Source :
-
Proceedings of the National Academy of Sciences of the United States of America . 3/19/2024, Vol. 121 Issue 12, p1-S50. 59p. - Publication Year :
- 2024
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Abstract
- TMC-anti and TMC-syn, the two topological isomers of [FeIV(O)(TMC)(CH3CN)]2+ (TMC = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane, or Me4cyclam), differ in the orientations of their FeIV=O units relative to the four methyl groups of the TMC ligand framework. The FeIV=O unit of TMC-anti points away from the four methyl groups, while that of TMC-syn is surrounded by the methyl groups, resulting in differences in their oxidative reactivities. TMC-syn reacts with HAT (hydrogen atom transfer) substrates at 1.3-to 3-fold faster rates than TMC-anti, but the reactivity difference increases dramatically in oxygen-atom transfer reactions. R2S substrates are oxidized into R²S=O products at rates 2-to-3 orders of magnitude faster by TMC-syn than TMC-anti. Even more remarkably, TMC-syn epoxidizes all the olefin substrates in this study, while TMC-anti reacts only with cis-cyclooctene but at a 100-fold slower rate. Comprehensive quantum chemical calculations have uncovered the key factors governing such reactivity differences found between these two topological isomers. [ABSTRACT FROM AUTHOR]
- Subjects :
- *ALKENES
*ABSTRACTION reactions
*ISOMERS
*EPOXIDATION
*METHYL groups
Subjects
Details
- Language :
- English
- ISSN :
- 00278424
- Volume :
- 121
- Issue :
- 12
- Database :
- Academic Search Index
- Journal :
- Proceedings of the National Academy of Sciences of the United States of America
- Publication Type :
- Academic Journal
- Accession number :
- 176207255
- Full Text :
- https://doi.org/10.1073/pnas.2319799121