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.