43195-77-3Relevant articles and documents
Sesquibicyclic Hydrazines: Oxidation Thermodynamics and Cation Radical Nitrogen ESR Splittings and UV Absorption Maxima
Nelsen, Stephen F.,Frigo, Timothy B.,Kim, Yaesil
, p. 5387 - 5397 (1989)
Diels-Alder addition of 1,3-cyclohexadiene to protonated 3,4-diazatricyclo2.5>non-3-ene (3), 2,3-diazabicyclohex-2-ene (4), and 6,7-diazabicyclonon-6-ene (5) gave 8, 6, and 9, respectively, and addition of 1,3-cycloheptadiene to 5 gave 10.The saturated compounds 7, 11, and 12 were prepared by hydrogenating 6, 9, and 10.Comparisons of Eo', vIP, cation radical ESR nitrogen splitting constants , and UV absorption maxima with values for other sesquibicyclic hydrazines and with AM1 semiempirical calculations are discussed.The doublenitrogen inversion barrier of 7.+ was determined by ESR to be 4.6 kcal/mol, within experimental error of that previously measured for 16-d12.+.Changing bicyclic ring size in sesquibicyclic hydrazines greatly affects the ease of oxidation and cation radical properties.Changes in ΔGo for first electron loss are usefully described a one dimensional in nitrogen pyramidality caused by the rings present regardless of their identity (using α(av) calculated by AM1).Calculation of nitrogen ESR splitting constants for the cation radicals requires averaging over the energy surface for bending at nitrogen.This problem is less well described as one dimensional in α(av) as the ring sizes are enlarged, and a(N) is calculated to be modestly sensitive to the identity of the bicyclic rings.Cation radical UV absorption spectra are not calculated usefully by semiempirical methods.The identity of the rings and not simply nitrogen pyramidality is clearly of importance, and this is not handled accurately enough by available calculations.
