The Effect of Temperature on the Formation of Benzyl Radical-Halide Ion Complexes in γ-Irradiated Organic Glassy Matrices

Autor: Izumida, Tatsuo, Fujii, Kuniaki, Ogasawara, Masaaki, Yoshida, Hiroshi
Zdroj: Bulletin of the Chemical Society of Japan; January 1983, Vol. 56 Issue: 1 p82-85, 4p
Abstrakt: Broad structureless charge-transfer (CT) bands of benzyl radical-halide ion (\dotBz- - -X−) complexes have been observed in 3-methylhexane (3MHx) and 2-methyltetrahydrofuran (MTHF) matrices containing BzCl and BzBr irradiated with γ-rays at 4.2 K. 3MHx and ethanol matrices containing BzI also showed the CT band when warmed from the irradiation temperature to 77 K. These observations are in marked contrast with previous ones in which the CT band was found to be present only in alkane matrices when irradiated at 77 K. The CT band has been found to shift to the blue with increasing matrix polarity, as expected from a large contribution of the solvation of the ion to the CT transition energy of the radical-anion complex. The observed nature and behavior of the CT bands indicates that the dissociative electron attachment reaction in the matrices is a stepwise process: The formation of a \dotBz- - -X−complex and its dissociation. These steps proceed readily in more polar environments and for lighter ions. For the electron attachment to BzI at 4.2 K, an even earlier step, an ionic entity prior to the C–I bond dissociation, was indicated.
Databáze: Supplemental Index