Synthesis and Electronic Phosphorescence of Dicyanooctatetrayne (NC10N) in Cryogenic Matrixes

Rod-like 1,8-dicyano-octa-1,3,5,7-tetrayne (NC10N) molecule was synthesized by UV-assisted coupling of rare-gas matrix-isolated cyanobutadiyne (HC5N) molecules. Detection of the targeted molecule was possible due to its strong orange-red (origin at 618 nm) electronic luminescence. Excitation spectra of this emission (a 3Σu+ – X 1Σg+ phosphorescence) gave access to studying the fully allowed H 1Σu+ – X 1Σg+ UV system of NC10N. The identification of observed spectral features was assisted with quantum chemical calculations. Certain regularities shaping the electronic spectroscopy of NC2nN molecules have been discussed.