Theoretical thermochemistry. 2. Ionization energies and proton affinities of AHn species (A = C to F and Si to Cl); heats of formation of their cations

1987 ◽  
Vol 91 (1) ◽  
pp. 155-162 ◽  
Author(s):  
John A. Pople ◽  
Larry A. Curtiss
Keyword(s):  
Heats Of Formation ◽  
Proton Affinities ◽  
Ionization Energies

Sulfenic acids in the gas phase. Preparation, ionization energies and heats of formation of methane-, ethene-, and benzenesulfenic acid

1988 ◽  
Vol 53 (9) ◽  
pp. 2140-2158 ◽  
Author(s):  
František Tureček ◽  
Libor Brabec ◽  
Tomáš Vondrák ◽  
Vladimír Hanuš ◽  
Josef Hájíček ◽  
...  
Keyword(s):  
Experimental Data ◽  
Gas Phase ◽  
Radical Cations ◽  
Appearance Energy ◽  
Heats Of Formation ◽  
Ionization Energies ◽  
Flash Vacuum Pyrolysis ◽  
Vacuum Pyrolysis ◽  
Mndo Calculations ◽  
Sulfenic Acids

Methane-, ethene-, and ethynesulfenic acids were generated in the gas phase by flash-vacuum pyrolysis of the corresponding tert-butyl sulfoxides at 400 °C and 10-4 Pa. Benzenesulfenic acid was prepared from phenyl 3-buten-1-yl sulfoxide at 350 °C and 10-4 Pa. The sulfenic acids were characterized by mass spectrometry Threshold ionization energies (IE) were measured as IE(CH3SOH) = 9·07 ± 0·03 eV, IE(CH2=CHSOH) = 8·70 ± 0·03 eV, IE(HCCSOH) = 8·86 ± 0·04 eV, and IE(C6H5SOH) = 8·45 + 0·03 eV. Radical cations [CH3SOH].+, [CH2=CHSOH].+, and [HCCSOH].+ were generated by electron-impact-induced loss of propene from the corresponding propyl sulfoxides and their heats of formation were assessed by appearance energy measurements as 685, 824, and 927 kJ mol-1, respectively. Heats of formation of the neutral sulfenic acids and the S-(O) (C), S-(O) (Cd), S-(O) (Ct) and S-(O) (CB) group equivalents were determined. The experimental data, supported by MNDO calculations, point to sulfenate-like structures (R-S-OH) for the sulfenic acids under study.

Diazen und andere Distickstoffhydride: Bildungswärmen, Dissoziationsenergien, Auftrittspotentiale, Protonenaffinitäten [1] / Diazene and other Dinitrogen Hydrides: Heats of Formation, Dissoziation Energies, Appearance Potentials, Proton Affinities [1]

1979 ◽  
Vol 34 (10) ◽  
pp. 1385-1390 ◽  
Author(s):  
Nils Wiberg ◽  
Gerd Fischer ◽  
Heinz Bachhuber
Keyword(s):  
Hydrogen Atom ◽  
Proton Affinity ◽  
Heat Of Formation ◽  
Heats Of Formation ◽  
Proton Affinities ◽  
Kcal Mole ◽  
Energy Data

AbstractIonisation and appearance potentials were obtained for diazene HN = NH (prepared by thermolysis of TOSN2H2M, M = Li, Na, K), isodiazene H2N = N (prepared by thermolysis of TOSN2H2CS and N2H4 microwave radiolysis, respectively), and other hydrides N2Hn (cf. Table I). The following energy data (kcal/mole) have been determined for diazene: heat of formation (32), enthalpy of isomerisation to isodiazene (13), NN-dissoziation energy (122), NH-dissoziation energy (81), hydrogen atom affinity (45), proton affinity (176).

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