| Popis: |
High-pressure mass spectrometry was used to measure adiabatic ionization potentials and proton affinitias for hydrazine, methylhydrazine, 1,l-dimethylhydrazine, and six tetraalkylhydrazines. Unusually large relaxation energies in the radical ions, which have VIP - aIP = 1.4-1.6 eV when only H and normal alkyl substituents are present, compared to 0.7 eV for typical amines, reflect the stabilization of the nearly planar hydrazine radical cations by charge delocalization in their three-electron T bonds. The proton affinities of hydrazines are lower than those of comparable amines by 4-6 kcal mol-I. The combined effects of lowered aIPs and lowered PAS decrease the B+-H bond-dissociation energies in protonated alkylhydrazines by ca. 20 kcal mol-I compared to those of alkylamines. |
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