Photochemistry of matrix-isolated diazoethane and methyldiazirine: ethylidene trapping?

Photolysis of matrix-isolated diazoethane (1a) at 8 K produces mainly ethene (4a), along with a small amount of 3-methyldiazirine (2a). ESR experiments employing a variety of irradiation conditions and matrix media (Ar, N 2 , Xe) show that triplet ethylidene (3T) is not an observable photoproduct. Similar experiments fail to reveal direct evidence for either singlet or triplet ethylidene by IR or UV-vis spectroscopy. Photolysis of nascent 3-methyldiazirine (2a) also fails to yield ethylidene. Deuterium substitution produces no detectable change in the chemistry