Reaction of diphenyldiazomethane with singlet oxygen studied by time-resolved IR spectroscopy.
The mechanism of the reaction of diphenyldiazomethane 4a with singlet oxygen has been investigated by nanosecond time-resolved UV-vis (LFP) and IR (step-scan) spectroscopy. The experiments were performed with fullerene (C60) as photosensitizer for the generation of (1)O2 in nonpolar solvents (toluene and CCl4). The UV-vis experiments allowed us to monitor the formation of benzophenone O-oxide 1a, while in the IR experiments the bleaching of 4a and the formation of benzophenone 7a and N2O was observed. The kinetic data were evaluated using Monte Carlo simulation and DFT calculations. These methods allow us to present a consistent mechanistic scheme for the reaction of 4a with (1)O2 and to explain why the elusive dioxadiazole 5a as key intermediate is not directly observed.
Torres-Alacan
Joel
J
Lehrstuhl für Organische Chemie II der Ruhr-Universität, D-44780 Bochum, Germany.
Sander
Wolfram
W
D001391:Azo Compounds / Q000737:chemistry*; D001577:Benzophenones / Q000138:chemical synthesis / Q000737:chemistry; D003198:Computer Simulation; D037741:Fullerenes / Q000737:chemistry; D007700:Kinetics; D008956:Models, Chemical; D015394:Molecular Structure; D009010:Monte Carlo Method; D010777:Photochemistry; D015203:Reproducibility of Results; D026082:Singlet Oxygen / Q000737:chemistry*; D013055:Spectrophotometry, Infrared / Q000379:methods; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D013997:Time Factors
D001391:Azo Compounds; D001577:Benzophenones; D037741:Fullerenes; C532721:diphenyldiazomethane; D026082:Singlet Oxygen; C069837:fullerene C60