An Investigation of 1,8-Diazafluorenylidene. A Carbene with Unusual Properties

Article abstract of DOI:10.1021/jo00370a011

Irradiation of 9-diazo-1,8-diazafluorene initiates a series of photochemical reactions that lead to isomerization to the diazirine and to loss of nitrogen to form a carbene.The carbene has a triplet ground state but reacts primarily from its upper singlet state.The chemical and physical properties of the diazo compound and the carbene are compared with those for 9-diazofluorene.The differences between these compounds are assigned tentatively to a combination of through-space interaction of the lone pair electrons of the heteroatomic ring atoms with the nonbonding in-plane orbital of the carbene carbon and the electron-withdrawing nature of the pyridine-like nitrogens.