Photoextrusion of Molecular Nitrogen from Annulated 5-Alkylidene-4,5-dihydro-1H-tetrazoles: Annulated Iminoaziridines and the First Triplet Diazatrimethylenemethane
hexahydronaphthyridine 22 which is also formed on thermolysis. − Irradiation of 13b in a 2-methyltetrahydrofuran or butyronitrile matrix at 77 K yields a triplet diradical showing a four-line EPR spectrum centred at 3362 G and a half-field transition (at 1669 G) with a hyperfine structure. The zero-field splitting parameters |D-hc| = 0.031 cm−1 and |E-hc| = 0.0014 cm−1 are obtained by simulation of