Premium
Spectral and kinetic measurements on a series of persistent iminoxyl radicals
Author(s) -
Eisenhauer Brian M.,
Wang Minghui,
Brown Richard E.,
Labaziewicz Henryk,
Ngo Maria,
Kettinger Karl W.,
Mendenhall G. David
Publication year - 1997
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/(sici)1099-1395(199710)10:10<737::aid-poc944>3.0.co;2-n
Subject(s) - chemistry , radical , kinetic energy , kinetics , electron paramagnetic resonance , reaction rate constant , computational chemistry , decomposition , spectral line , series (stratigraphy) , photochemistry , medicinal chemistry , organic chemistry , nuclear magnetic resonance , paleontology , physics , quantum mechanics , astronomy , biology
A series of new iminoxyl radicals, Et 3 C(C=NO · )Bu‐ tert ( 1 ), tert ‐C 5 H 11 (C=NO · ) Bu‐ tert ( 2 ), ( tert ‐C 5 H 11 ) 2 C=NO · ( 3 ), Et 3 C(C=NO · )Ph ( 4 ), PhCH 2 CMe 2 (C=NO · )Bu‐ tert ( 5 ), PhCMe 2 (C=NO · )Bu‐ tert ( 6 ) and Me 2 CH(C=NO · )C 5 H 11 ‐ tert ( 7 ), was characterized by EPR and in some cases visible spectra and decay kinetics in solution. Isolation of 1H and 3‐ tert ‐butyl‐4,4‐diethyl‐5‐methyl‐4,5‐dihydro‐5‐isoxazolol ( 9 ) among the decomposition products of 1 was consistent with a previously unrecognized mode of iminoxyl reaction in which the initial step is an internal β‐H abstraction. Molecular orbital calculations on H 2 C=NO · indicate a C–N–O angle of about 140° and a 10 kcal mol −1 barrier to inversion. Rate constants for the reaction of tert ‐Bu 2 C=NO · (8) with a series of olefins were measured. © 1997 John Wiley & Sons, Ltd.