Reaction of vinyl radical with oxygen: A matrix isolation infrared spectroscopic and theoretical study

The reaction of vinyl radical with molecular oxygen in solid argon has been studied using matrix isolation infrared absorption spectroscopy. The vinyl radical was produced through high frequency discharge of ethylene. The vinyl radical reacted with oxygen spontaneously on annealing to form the vinylperoxy radical C2H3OO with the O-O bond in a trans position relative to the C-C bond, which is characterized by O-O stretching and out-of-plane CH2 bending vibrations at 1140.7 and 875.5 cm(-1). The vinylperoxy radical underwent visible photon-induced dissociation to the CH2OH(CO) complex or CH2OH+CO, which has never been considered in previous studies. The CH2OH(CO) product was predicted to be more thermodynamically accessible than the previously reported major HCO+H2CO channel, and is most likely produced by hydrogen atom transfer from the first-formed H2CO-HCO pair in solid argon. (C) 2005 American Institute of Physics.