Cryogenic photolysis studies. Part 2.—Infrared spectrum of nitrosomethane monomer

The photolysis of trans-t-butyl nitrite in an argon matrix at 20 K gave rise to absorptions due to acetone, nitrosomethane and cis-t-butyl nitrite. Isomerisation was dominant at higher concentrations; decomposition was dominant at lower concentrations. Vaporisation of nitrosomethane dimer and trapping of the products at 20 K yielded the spectrum of nitrosomethane monomer and the trans dimer. Ultra-violet irradiation dissociated the dimer, leaving nitrosomethane monomer. On warming to room temperature and recooling to 20 K the cis-nitrosomethane dimer was obtained, which could be dissociated by photolysis to regenerate the monomer. A vibrational assignment of the monomer is presented.