TENTATIVE IDENTIFICATION OF C5N2 IN RARE-GAS MATRICES

A new cyanocarbon is formed in a discharge of dicyanoacetylene (NC4N) and studied in rare gas matrices through its visible absorption, laser -induced fluorescence, and laser excitation spectra. The spectrum, wit h origin at 22737 cm-1 in an argon matrix, exhibits strong progression s in a vibrational mode around 2000 cm-1, typical for a linear molecul e with multiple bonds. Isotopic studies suggest that the carrier conta ins two equivalent nitrogen atoms and probably five carbons. They also point to a centro-symmetric molecule with two equivalent carbon atom pairs. Given this information, we assign the carrier of this spectrum tentatively to a linear cumulenic NC5N or CNC3NC. Chemical evidence su ggests it may be formed by the reaction of C atoms with NC4N or its is omer NC3NC.