Behavior of alkyl radical pairs in urea channels

Autor:	H. L. Casal, F. W. Hartstock, R. J. Kolt, D. D. M. Wayner, J. M. Park, David Griller, D. M. Northcott
Rok vydání:	1989
Předmět:	chemistry.chemical_classification Photodissociation General Engineering Photochemistry Inclusion compound chemistry.chemical_compound chemistry Polymer chemistry Urea Physical and Theoretical Chemistry Aliphatic compound Single crystal Alkyl Laser beams
Zdroj:	The Journal of Physical Chemistry. 93:1666-1670
ISSN:	1541-5740 0022-3654
DOI:	10.1021/j100341a094
Popis:	Photolysis of single crystals of urea/diacyl peroxide complexes at 10 K gave pairs of alkyl radicals that were separated by two molecules of carbon dioxide. At elevated temperatures the spectra became well-resolved as rotation of the radical centers became fast on the EPR time scale. The maximum resolution of the EPR hyperfine couplings was achieved when the separation between the radicals was greatest. The temperature for the onset of rapid rotation was markedly dependent on the length of the diacyl peroxide. Two radical rearrangements in the urea channels were studied: the cyclopropylmethyl ring opening and the 5-hexenyl radical cyclization. The former was virtually unaffected by the presence of the urea host while the cyclization of the 5-hexenyl radical showed a marked matrix effect.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::fb2a363ba7eba636e6425cf2aaf29291 https://doi.org/10.1021/j100341a094