Photolysis of Dimethylcarbamoyl Azide in an Argon Matrix: Spectroscopic Identification of Dimethylamino Isocyanate and 1,1-Dimethyldiazene

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)N3 → 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.