Synthesis and ESR of a nitroxide biradical of approximateD2h symmetry

Autor:	L. C. Brunel, Claude Fabre, André Rassat, Daniel Jaouen, Claude Chachaty, Serge Gambarelli
Rok vydání:	1995
Předmět:	Nitroxide mediated radical polymerization chemistry.chemical_compound Ethanol Chemistry Computational chemistry Condensation Pyridine Formaldehyde Physical chemistry General Materials Science General Chemistry Symmetry (physics) Spectral line
Zdroj:	Magnetic Resonance in Chemistry. 33:S129-S133
ISSN:	1097-458X 0749-1581
DOI:	10.1002/mrc.1260331320
Popis:	A nitroxide biradical 2,6-dioxy-2,6-diaza-1,1,3,3,5,5,7,7-octamethyldicyclopentano[b;e]pyridine (1) and the corresponding monoradical (2-oxy-6-hydroxy) were prepared starting from 2,2,5,5-tetramethyl-3-oxopyrrolidine by successive condensation with formaldehyde (KOH) or DMF (K in THF), NH4OAc and oxidation (Na2WO4-H2O2). In ethanol, biradical 1 shows a quintet (|J| ≫ |aN| = 14.6 G). In frozen ethanol solution, the experimental spectra (X-band at 120 K and 240 GHz at 7, 15 and 25 K) can be computer simulated with the following parameters: D = −64 G; E = 1 G; gxx = 2.0093; gyy = 2.0064; gzz = 2.0020; Axx = Ayy = 8 G; Azz = 32.2 G. From the temperature dependence of the high-field spectra, D is found to be negative.
Databáze:	OpenAIRE
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