THE PHOTOCHEMISTRY OF 1,4-DIHYDRO-5H-TETRAZOLE DERIVATIVES ISOLATED IN LOW-TEMPERATURE MATRICES

Article abstract of DOI:10.1016/0040-4020(89)80053-5

Six 1,4-dihydro-5H-tetrazole (tetrazoline) derivatives have been photolysed in Ar and N2 matrices at 12 K.The dimethyltetrazolinone (1a) gave as the major product the same diaziridinone obtained previously from solution photolysis, but it also underwent a novel cleavage to MeNCO and, presumably, methyl azide.Iminotetrazolines (3a) and (3b) gave the corresponding carbodiimides (5a) and (5b), and iminodiaziridines (4a) and (4b); while the tetrazolinethiones (7a) and (7b) gave carbodiimides (8a) and (8b), respectively.Photolysis of the vinyl substituted tetrazolinone (9) proceeded differently in inert ambient-temperature solutions and low-temperature matrices.In the former an imidazolone (10) was the sole isolable product, while in the latter formation of diaziridinone (15) competed with an alternative cleavage giving t-butyl isocyanate and vinyl azide.THese results are best interpreted on the basis of an intermediate biradical, which, however, could not be detected directly by matrix ir. spectroscopy.