CHN₂^-: A biradical anion and a potentially new type of reactive intermediate

MCSCF calculations reveal that diazirinyl anion (1), its conventional C_s structure resulting from deprotonation of diazirine (c-CH₂N₂), is less stable than its open C_2v isomer (2) in which the two nitrogens are no longer bound. The latter species represents a novel type of reactive intermediate, a biradical anion. It is calculated to have a large electron binding energy (0.80 eV) and is an experimentally attractive target. G2 theory has been used to provide the heats of formation of diazomethane and diazirine, two important compounds whose experimental energies are not well established.