Generation and IR spectroscopic study of benzyl radical

The benzyl radical C₆H₅CH₂ has been obtained by gas phase pyrolysis of two different precursors, benzyl bromide and dibenzyl, and studied in an argon matrix at 12 K by IR spectroscopy. Similarly, the deuterosubstituted benzyl radicals, C₆H₅CD₂ and C₆D₅CH₂, have been investigated. The assignment of the IR bands of the benzyl radical and its deuteroanalogs to fundamental modes and a calculation of the valence force field have been performed. The obtained data give evidence of sp² hybridization of the methylene carbon atom and delocalization of the electron density between the ring and the CH₂ group, and are in good agreement with the planar structure of the radical.These results were presented for the first time in O. M. Nefedov's plenary lecture at X IUPAC Conference on Physical Organic Chemistry (Haifa, Israel, August 1990).Deceased July, 1986.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1499–1502, August, 1993.