ISSN:
0941-1216
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
cis/trans-Isomerization of 2,2′-Diethyl-5,5′-dimethoxy-4,4′-binaphthylidene-1,1′-dione from a Radical IntermediateThe 1H-NMR spectrum of 2,2′-diethyl-5,5′-dimethoxy-4,4′-binaphthylidene-1,1′-dione (1) shows flat-topped peaks at room temperature. At higher temperatures sharp peaks are observed while at deep temperatures the spectrum consists of two separated sets of lines. We propose a cis/trans-isomerization with coalescence at room temperature. The rate constants of this isomerization were obtained by dynamic line shape analysis, and an energy barrier of about 74 kJ mol-1 was calculated. The intermediate biradical was proved by ESR spectroscopy.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/prac.19963380112
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