The ESR study of the structure and reactivity of α-ketoradicals, derivatives of (CF3)3CC(O)C(O)CF3

Autor: S. R. Sterlin, N. N. Bubnov, E. N. Shaposhnikova, Boris Tumanskii, A. I. Chernyavskii, S. P. Solodovnikov, Ivan V. Stankevich, Anatolii L. Chistyakov
Rok vydání: 1998
Předmět:
Zdroj: Russian Chemical Bulletin. 47:60-65
ISSN: 1573-9171
1066-5285
DOI: 10.1007/bf02495510
Popis: The structure and reactivity of α-ketoradicals, derivatives of (CF3)3CC(O)C(O)CF3 (1), were studied by ESR spectroscopy. The photoreduction of α-diketone1 in a solution of cyclohexane in perfluorodipentyl ether results in the formation of radicals of two types, (CF3)3CC(2)(O(4))·C(3)(O(6)H)CF3 (1a) and (CF3)3C·C(OH)C(O)CF3 (1b) in a ∼40∶1 ratio. The degree of delocalization of the spin density in two conformers of radical1a was calculated by the MNDO/PM3 method in the UHF approximation. It was established that radicals1a and1b are capable of reversible dimerization. The rate constant of dimerization and the enthalpy of the radical—dimer equilibrium were measured for radical1a. A decrease in the rate of dimerization of radical1a upon addition of complexing solvents ((CF3)3COH andp-CF3C6H4CF3) was found. The influence of the solvents on the rate of dimerization was also detected for α-ketoradical (CF3)3CC(O)·C(OSiMe2Ph)CF3 (1c).
Databáze: OpenAIRE
Externí odkaz: