Cyclopentadienylidene. A Matrix Isolation Study Exploiting Photolysis with Unpolarized and Plane-Polarized Light

Article abstract of DOI:10.1021/ja00407a040

Diazocyclopentadiene (1) was photolyzed in N2, CO, and other low-temperature matrices.The resulting carbene, cyclopentadienylidene (2), was characterized by its UV and IR spectra, and its thermal dimerization and reaction with CO were observed.Photolysis of 1 with plane-polarized light gave matrices exhibiting linear dichroism.Comparison of dichroic IR and UV spectra revealed that the photolysis proceeds via an excited A₁ state of the diazo compound.Plane-polarized irradiation of the corresponding ketene (4) in CO matrices resulted in photoreorientation of the molecules of 4 without significant loss.