Red light-induced reaction of NO2 with 2,3-dimethyl-2-butene in a low-temperature argon matrix

Article abstract of DOI:10.1016/0584-8539(94)E0056-G

Red light-induced oxygen atom transfer from NO2 to 2,3-dimethyl-2-butene has been investigated in a low-temperature argon matrix.The IR spectra of a reaction intermediate identified as an alkyl nitrite radical and two final products, tetramethyloxirane and 3,3-dimethyl-2-butanone (pinacolone), were observed.From analysis of the absorbance growth of the IR bands, first-order rate constants were determined by least-square fitting.Based on these results and those of our earlier works on NO2 photoreactions with other alkenes, a reaction mechanism is proposed that involves oxygen atom transfer from NO2 to the C=C bond of 2,3-dimethyl-2-butene to give a short-lived singlet oxirane biradical.Alkyl nitrite radical is produced by a recombination of the transient biradical with NO trapped in the cage of the matrix.Tetramethyloxirane and pinacolone emerge from secondary photolysis of the trapped alkyl nitrite radical.