Abstract The thermal N 2 exchange of a number of 15 N-labelled diazo compounds was studied in solution. The compounds involved were 3-diazo-1-methylindolin-2-one (1), 9- diazofluorene (2), 5-diazo-1, 3-cyclopentadiene-1, 2, 3, 4-tetracarbonitrile (3), 2-diazo-2H- imidazole-4, 5-dicarbonitrile (4), 4-diazocyclohexa-2, 5-dienone (5), and the conjugate acids of 4 and 5, namely 4, 5-dicyano-1H-imidazole-2-diazonium ion (6) and 4- ...
