Transient species and product formation from electronically excited tetranitromethane

Tetranitromethane (TNM) in polar or non-polar solvents was electronically excited with 248 nm, 15 ns pulses from an excimer laser and the transient species formed were detected and characterized with nanosecond time-resolved absorption spectroscopy. The experimental findings indicate that in aerated or deaerated polar solvents the NO2 radical and the nitroform anion (NO2)3C–, with absorption maximum at 350 nm, are formed. In non-polar solvents, however, electronic excitation of TNM leads to the formation of NO2 radical and a transient species with absorption maximum at 307 nm, which is attributed to the previously undetected trinitromethyl radical, (NO2)3C˙. Prolonged irradiation of TNM in non-polar solvents results in the formation of nitroform, (NO2)3C—H, with an absorption maximum at 290 nm, which is probably generated by (NO2)3C˙via hydrogen abstraction from the solvent. The non-polar solvent radicals generated by the hydrogen-abstraction reaction combine with NO2 radicals in the solution to form nitroalkane molecules.