Photolysis of a 2-tetbazeio from an enehydrazine

Photolysis of the 2-tetrazene $\text{1}$ gives the triazole $\text{2}$ by homolysis of one single N,N-bond. The formation of the other products $\text{4}$ – $\text{13}$ can be rationalized by regarding the aza-allyl radical $\text{3}$ as a common precursor.