1,6-Dihydro-1,2,4,5-tetrazine, a Neutral Homoaromatic System

Article abstract of DOI:10.1021/jo00323a032

¹H NMR spectroscopy of some 1,6-dihydro-3-aryl(alkyl)-1,2,4,5-tetrazines and their conjugate bases and acids, at various temperatures, shows that these species are all homoaromatic.The hydrogens at position 6 have a different orientation toward the aromatic ring; one is oriented above and the other away from the aromatic ring, thus resulting in a large difference in chemical shift.The various parameters (ΔH(excit.), ΔS(excit.), and ΔG(excit.)) are determined by dynamic NMR measurements.