INVESTIGATIONS ON DOUBLY N-15 LABELED ISOCYANOGEN (CNCN)

The doubly nitrogen-15 labeled isotopomer CN-15CN-15 of isocyanogen (CNCN) has been prepared by a known route in three steps from [N-15(2)]hydrazine sulfate and quadricyclanone. The chemical reactivity of CN-15CN-15 has been explored. Most of the typical isonitrile reactions are too slow to compete with the polymerization of isocyanogen which starts as low as -80-degrees-C; defined products were only obtained on bromination to Br2CNCN (7) and on FVT at 750-degrees-C to give partial conversion to cyanogen (NCCN). The N-15 and C-13 NMR spectra of 1, 4, CN-15CN-15, N-15CCN-15, and [N-15(2)]7 are discussed; important aspects are the previously "missing" cyano group in CNCN which has now been identified and an unusually large C-13-N-15 coupling (1J = 48.9 Hz) in the central bond of isocyanogen.