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The Reaction of Permanganyl Chloride with Olefins: Intermediates and Mechanism as Derived from Matrix‐Isolation Studies and Density Functional Theory Calculations
Author(s) -
Wistuba Tobias,
Limberg Christian
Publication year - 2001
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 - 10.1002/1521-3765(20011105)7:21<4674::aid-chem4674>3.0.co;2-l
Subject(s) - density functional theory , matrix isolation , chemistry , computational chemistry , reaction mechanism , matrix (chemical analysis) , moiety , chloride , infrared spectroscopy , organic chemistry , catalysis , chromatography
Density functional theory (DFT) calculations predict that the [2+3] addition of tetramethylethylene (TME) to the MnO 2 moiety of MnO 3 Cl is thermodynamically favoured over [2+1] addition (epoxidation), while the kinetic barriers for both reactions are of comparable height. However, in an experimental investigation of the TME/MnO 3 Cl system by means of matrix‐isolation techniques, selective formation of the epoxidation product [ClO 2 Mn{O[C(CH 3 ) 2 ] 2 }] ( 1 ) was observed. Compound 1 was characterised by IR spectroscopy with the aid of isotopic‐enrichment experiments in combination with DFT frequency calculations. This result, at first sight surprising, is supported by studies in solution, and, even with the numerically equal energy barriers suggested by the calculations, it can be rationalised in terms of the much broader reaction channel leading to epoxidation as opposed to the much more narrow approach path for formation of the glycolate.