Special effects of an unusually large neutral to radical cation geometry change. Adiabatic ionization energies and proton affinities of alkylhydrazines

Autor:	Mark R. Willi, Timothy B. Frigo, Stephen F. Nelsen, Michael Meot-Ner
Rok vydání:	1984
Předmět:	Methylhydrazine Proton Chemistry Inorganic chemistry Protonation General Chemistry Photochemistry Biochemistry Catalysis Ion Colloid and Surface Chemistry Radical ion Ionization Proton affinity Ionization energy
Zdroj:	Journal of the American Chemical Society. 106:7384-7389
ISSN:	1520-5126 0002-7863
DOI:	10.1021/ja00336a015
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.
Databáze:	OpenAIRE
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