Sterically Hindered Free-Radicals .22. Dimerization and Epr Spectroscopy of Indanedionyl and 9-Acylfluorenyl Radicals
Loading...
Date
Authors
Harnack, C.
Krull, W.
Lehnig, M.
Neumann, W. P.
Zarkadis, A. K.
Journal Title
Journal ISSN
Volume Title
Publisher
Royal Society of Chemistry
Abstract
Type
Type of the conference item
Journal type
peer reviewed
Educational material type
Conference Name
Journal name
Journal of the Chemical Society-Perkin Transactions 2
Book name
Book series
Book edition
Alternative title / Subtitle
Description
2-Phenylindanedionyl radicals 5a, their p- and o-monosubstituted derivatives and related compounds 5b-h recombine by C-C bond formation giving 6a-h. In contrast, o-substituted derivatives 5i-k and the 2-tert-butylindanedionyl radicals 5I react to give the enol ethers 10a-d by C-O coupling. The EPR data indicate that the substituents are more bulky in 5i-I than in 5a-h. From the proton splitting constants it is concluded that 5a is planar and 5h nearly planar (twist angle of the phenyl group ca. 30-degrees). The phenyl group in 5i is twisted considerably with an angle of about 50-degrees. The g values of 5i-k are larger than those of 5a-h indicating a higher spin density in the carbonyl groups. 9-Acylfluorenyl radicals 12b-c, representing the planar conformations of diarylmethyl radicals 1 c, d, give no enol ethers like 4, but recombine by C-C bond formation yielding 13b-c. Their g values indicate that the acyl groups are twisted out of the radical plane.
Description
Keywords
triphenylmethyl radicals, stabilization, diphenylmethyl, dimers, endor
Subject classification
Citation
Link
<Go to ISI>://A1994NQ34100021
http://pubs.rsc.org/en/Content/ArticleLanding/1994/P2/p29940001247
http://pubs.rsc.org/en/Content/ArticleLanding/1994/P2/p29940001247
Language
en
Publishing department/division
Advisor name
Examining committee
General Description / Additional Comments
Institution and School/Department of submitter
Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας