A theoretical study of the gas phase (proton affinity) and aqueous (pKa) basicity of a series of 150 pyrazoles

2015 ◽  
Vol 39 (4) ◽  
pp. 2861-2871 ◽  
Author(s):  
Marta Marín-Luna ◽  
Ibon Alkorta ◽  
José Elguero
Keyword(s):  
Gas Phase ◽  
Proton Affinity ◽  
Theoretical Study ◽  
Proton Affinities ◽  
Aqueous Pka

Experimental proton affinities and pKas covering a range of 208 kJ mol−1 and 10.3 pKa units, respectively, have been analyzed theoretically.

Theoretical study of the proton affinities of 2-, 3-, and 4-monosubstituted phenolate ions in the gas phase by means of MINDO/3, MNDO, and AM1

1990 ◽  
Vol 11 (3) ◽  
pp. 269-290 ◽  
Author(s):  
R. Voets ◽  
J.-P. Fra?ois ◽  
J. M. L. Martin ◽  
J. Mullens ◽  
J. Yperman ◽  
...  
Keyword(s):  
Gas Phase ◽  
Theoretical Study ◽  
Proton Affinities

Theoretical study of the proton affinities of 2-, 3-, and 4-monosubstituted pyridines in the gas phase by means of MINDO/3, MNDO, and AM1

1989 ◽  
Vol 10 (4) ◽  
pp. 449-467 ◽  
Author(s):  
R. Voets ◽  
J.-P. François ◽  
J. M. L. Martin ◽  
J. Mullens ◽  
J. Yperman ◽  
...  
Keyword(s):  
Gas Phase ◽  
Theoretical Study ◽  
Proton Affinities

scholarly journals Theoretical study of the energetics of carboxylic O–H bond cleavage in the para- and meta-substituted benzoic acid derivatives

2015 ◽  
Vol 8 (1) ◽  
pp. 70-77 ◽  
Author(s):  
Peter Škorňa ◽  
Adam Vagánek ◽  
Peter Poliak ◽  
Erik Klein
Keyword(s):  
Gas Phase ◽  
Theoretical Study ◽  
Bond Cleavage ◽  
Computational Method ◽  
Benzoic Acids ◽  
Proton Affinities ◽  
Benzoic Acid Derivatives ◽  
Hammett Constants ◽  
Carboxylate Anions ◽  
Substituted Benzoic Acids

Abstract Gas phase bond dissociation enthalpies (BDE) of para- and meta-substituted benzoic acids and proton affinities (PA) of their carboxylate anions were investigated using the B3LYP/6-311++G** method for 15 substituents with various electron-donating and electron-withdrawing effects. The employed computational method provided BDE and PA values in fair agreement with experimental data. The substituent effect on BDEs and PAs was analyzed in terms of Hammett constants. Found dependences exhibit satisfactory linearity and enable quick estimation of BDEs and PAs from the Hammett constants.

Experimentally determined proton affinities of 4-methyl-3-penten-2-one, 2-propyl ethanoate, and 4-hydroxy-4-methyl-2-pentanone in the gas phase

1986 ◽  
Vol 64 (12) ◽  
pp. 2368-2370 ◽  
Author(s):  
Afaf Kamar ◽  
Alexander Baldwin Young ◽  
Raymond Evans March
Keyword(s):  
Gas Phase ◽  
Proton Affinity ◽  
Mesityl Oxide ◽  
Proton Affinities ◽  
Storage Duration ◽  
Diacetone Alcohol ◽  
Ion Storage ◽  
Protonated Species

Proton affinities have been determined for 4-methyl-3-penten-2-one, 2-propyl ethanoate, and 4-hydroxy-4-methyl-2-pentanone in the gas phase at 333 K. A quadrupole ion store (QUISTOR) was employed to study mass spectrometrically the equilibrium between a species of known proton affinity and one of the above compounds; equilibrium between protonated species was monitored over an ion storage duration of 100 ms. The values of the proton affinities were found to be 870.5 ± 0.8 kJ mol−1 for 4-methyl-3-penten-2-one (mesityl oxide); 842.7 ± 0.6 kJ mol−1 for 2-propyl ethanoate; and 831.6 ± 0.8 kJ mol−1 for 4-hydroxy-4-methyl-2-pentanone (diacetone alcohol).

Thermochemical parameters for organic radicals and radical ions. Part 2. The protonation of hydrocarbon radicals in the gas phase

1982 ◽  
Vol 60 (24) ◽  
pp. 3011-3018 ◽  
Author(s):  
A. Martin de P. Nicholas ◽  
Russell J. Boyd ◽  
Donald R. Arnold
Keyword(s):  
Gas Phase ◽  
Proton Affinity ◽  
Radical Cation ◽  
Radical Cations ◽  
Basis Sets ◽  
Thermochemical Cycle ◽  
Hydrocarbon Radical ◽  
Proton Affinities ◽  
Hartree Fock ◽  
Conjugate Base

A thermochemical cycle is used to estimate the gas phase acidity of several hydrocarbon radical cations: hydrocarbon radical cation (pKa), methane (≥ 86.5 ± 1), ethane(101 ± 1, 102 + 1), ethylene (≥ 125 ± 2), acetylene (118 ± 3, 122 ± 1), propene(124 ± 1, 122 ± 1), cyclopropane (≥ 134, ≥ 131), benzene (147 ± 1), and toluene (139 ± 1, 140). Similarly, proton affinities of the conjugate base, the hydrocarbon radical, are estimated.An estimate of the proton affinity is obtained using abinitio MO calculations. A Hartree–Fock proton affinity, PAHF(R•)g is defined as the difference in the computed energies of a radical cation and its conjugate base at the Hartree–Fock level. Calculations at the SCF level are carried out using both the minimal (STO-3G) and extended basis sets, without (3-21G, 4-31G, and 6-31G) and with (4-31G* and 6-31G*) polarization functions on carbon.The agreement between the thermochemical and abinitio estimates of the proton affinity is satisfactory.

Photoelectron Spectroscopy and Theoretical Study of AlnC5-/0 (n = 1-5) clusters: Structural Evolution, Relative Stability of Star-Like Cluster, and Planar Tetracoordinate Carbon Structure

2021 ◽  
Author(s):  
Chao-Jiang Zhang ◽  
Peng Wang ◽  
Xi-Ling Xu ◽  
Hong-Guang Xu ◽  
Weijun Zheng
Keyword(s):  
Gas Phase ◽  
Photoelectron Spectroscopy ◽  
Relative Stability ◽  
Theoretical Study ◽  
Structural Evolution ◽  
Carbon Structure ◽  
Anion Photoelectron Spectroscopy

The AlnC5- (n = 1-5) clusters were detected in the gas-phase and were investigated by mass-selected anion photoelectron spectroscopy. The structures of AlnC5-/0 (n = 1-5) were explored by theoretical...

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