Visible Light-Induced Oxygen Transfer from Nitrogen Dioxide to Ethyne and Propyne in a Cryogenic Matrix. 1. Identification of Products

Article abstract of DOI:10.1021/j100098a006

Photochemical reaction of ethyne*NO2 and propyne*NO2 pairs isolated in solid Ar has been observed at wavelengths as long as 582 nm (HC<*>CH*NO2) and 615 nm (CH3C<*>CH*NO2).Continuous wave dye laser radiation was used to excite the reactants, and the chemistry was monitored by FT-infrared spectroscopy.In the case of ethyne + NO2, the sole products were CH2=C=O and NO.The reaction of NO2 with propyne gave methylketene plus a trapped intermediate, CH3C(=NO^.)C(=O)H (formyl methyl iminoxy radical).Infrared spectra of this radical are reported for the first time.Product identification was based on D, 18O, and 15N isotopic substitution.Selective interconversion with tuned visible laser light revealed the presence of four conformers, most probably originating from isomerism about the C-C and the C=N bonds.Photoelimination of NO from the iminoxy radical was observed at wavelengths as long as 625 nm.Propynol and methylketene could be identified among the secondary photolysis products.