Photolysis of dimethylcarbamoyl azide in an argon matrix: Spectroscopic identification of dimethylamino isocyanate and 1,1-dimethyldiazene

Abstract

The UV photolysis of dimethylcarbamoyl azide has been investigated in an argon matrix at cryogenic temperatures. The products of the photolysis were identified by infrared spectroscopy supported by quantum-chemical calculations. Sequential formation of dimethylamino isocyanate (Me2N-NCO), 1,1-dimethyldiazene (Me2N=N), and ethane was established. Therefore, the major decomposition channel is identified as Me2NC(O)N 3 → Me2N-NCO → Me2N=N → Me-Me, via consecutive N2, CO, and N2 eliminations. Ground-state geometries, vibrational frequencies, IR intensities, and UV excitation energies of the transient dimethylamino isocyanate and 1,1-dimethyldiazene have been computed using the B3LYP and SAC-CI methods and the aug-cc-pVTZ basis set.