Gas-phase reactions of weak Broensted bases I-, PO3-, HSO4-, FSO3-, and CF3SO3- with strong Broensted acids H2SO4, FSO3H, and CF3SO3H. A quantitative intrinsic superacidity scale for the sulfonic acids XSO3H (X = HO, F, and CF3)

Viggiano, A. A.; Henchman, Michael; Dale, F.; Deakyne, Carol A.; Paulson, John F.

doi:10.1021/ja00037a039

Cited by 119 publications

(98 citation statements)

References 1 publication

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“…[20] This value is in excellent agreement with the results of an ab initio MO calculation: At the MP2/6-311ϩϩG(d,p)//HF/6-31ϩG(d) level of theory the deprotonation enthalpy (∆H°) of H 2 SO 4 at 0 K was obtained as 1300 kJ mol -1 .…”

Section: Introductionsupporting

confidence: 85%

Gas-Phase Acidities of Nine Sulfur Oxoacids of Composition [H2,S,On] (n = 1–4)

Otto

Steudel

2000

Eur. J. Inorg. Chem.

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Section: Introductionsupporting

confidence: 85%

Gas-Phase Acidities of Nine Sulfur Oxoacids of Composition [H2,S,On] (n = 1–4)

Otto

Steudel

2000

Eur. J. Inorg. Chem.

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“…It should be noted that the calculated GA of 1268.2 kJ mol À1 (G3 mod level) is nearly identical to the experimental value of (1265 AE 10) kJ mol À1 . [56] The results of the vertical and the relaxed CCC models differ slightly by 6 kJ mol…”

Section: The Me 3 Nhmentioning

confidence: 93%

Anchor Points for the Unified Brønsted Acidity Scale: The rCCC Model for the Calculation of Standard Gibbs Energies of Proton Solvation in Eleven Representative Liquid Media

Himmel

Goll

Leito

et al. 2011

Chemistry A European J

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The COSMO cluster-continuum (CCC) solvation model is introduced for the calculation of standard Gibbs solvation energies of protons. The solvation sphere of the proton is divided into an inner proton-solvent cluster with covalent interactions and an outer solvation sphere that interacts electrostatically with the cluster. Thus, the solvation of the proton is divided into two steps that are calculated separately: 1) The interaction of the proton with one or more solvent molecules is calculated in the gas phase with high-level quantum-chemical methods (modified G3 method). 2) The Gibbs solvation energy of the proton-solvent cluster is calculated by using the conductor-like screening model (COSMO). For every solvent, the solvation of the proton in at least two (and up to 11) proton-solvent clusters was calculated. The resulting Gibbs solvation energies of the proton were weighted by using Boltzmann statistics. The model was evaluated for the calculation of Gibbs solvation energies by using experimental data of water, MeCN, and DMSO as a reference. Allowing structural relaxation of the proton-solvent clusters and the use of structurally relaxed Gibbs solvation energies improved the accordance with experimental data especially for larger clusters. This variation is denoted as the relaxed COSMO cluster-continuum (rCCC) model, for which we estimate a 1σ error bar of 10 kJ mol(-1) . Gibbs solvation energies of protons in the following representative solvents were calculated: Water, acetonitrile, sulfur dioxide, dimethyl sulfoxide, benzene, diethyl ether, methylene chloride, 1,2-dichloroethane, sulfuric acid, fluorosulfonic acid, and hydrogen fluoride. The obtained values are absolute chemical standard potentials of the proton (pH=0 in this solvent). They are used to anchor the individual solvent specific acidity (pH) scales to our recently introduced absolute acidity scale.

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“…Hence, we find the decided acidic nature of aqueous hydrogen chloride and the decided basic nature of hydrated ammonia. Further, addition of the base, more commonly known as nitric "acid", to anhydrous liquid HF, leads to fluoride ion formation and the protonation of nitric acid, as shown in Equation (4): [31] Gordon W. Driver [19] Br À -1354 [15] I À -1315 [15] [HSO 4 ] À 1304.5 1295 AE 11 [20] [FSO 3 ] À 1258.6 1255 [21] [ClO 4 ] À 1268.9 1200 AE 59 [22] DBU [c] 1043.6 1049 [23] 1-methylimidazole 958.5 958 [15] pyridine 924.1 924 [15] NH 3 859.5 854 [15] H 2 O 693.4 697 [15] [a] This work, using the Firefly QC package (FIREFLY v7.1.G, build 5618, [24] which is partially based on the GAMESS (US) [25] source code), at the MP2 6-311 + G(d,p) computational level (vibrational analyses were performed to ensure optimised geometries were at the true energy minimum). Values in parentheses are those given in ref.…”

Section: Liquid Protic Moleculesmentioning

confidence: 99%

“…2.5 [93] 10.75 [2] 0.65 [94] 5.46 [98] 4.9 [96] --CF 3 CO 2 H 1352.1 [c] 3.51 [99] 12.65 [2] 0.00 [90] ----H 2 SO 4 1295 [20] 1.99 [100] 7.29 [101] À9 [33] -1.62 [102] 3.1 [80] HOTf 1278 [33] 0.3 [1] /f.d.…”

Section: Protic Molecules In Molecular Liquidsmentioning

confidence: 99%

Brønsted Acidity and the Medium: Fundamentals with a Focus on Ionic Liquids

2011

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Fundamental aspects of Brønsted acidity in ionic liquid systems, in relation to those of simple protic molecules in the gas phase, pure protic molecules in the condensed phase and solutions of protic molecules in molecular systems, are presented. The variety of acidities possible, beyond those observed in aqueous systems, is emphasised and discussed in terms of differences of solvent levelling, ionisation, dissociation, homo-/hetero-conjugate ion speciation and the stabilisation of proton-transfer products from solvent to solvent. It is argued that data regarding aqueous systems do not necessarily explain acid/base behaviour in other liquids satisfactorily. Methods of measuring acidity are reviewed, particularly by spectrophotometry and electrochemistry and recommendations proffered for estimating speciation and acidity of ionic liquids of various complexities.

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Gas-phase reactions of weak Broensted bases I-, PO3-, HSO4-, FSO3-, and CF3SO3- with strong Broensted acids H2SO4, FSO3H, and CF3SO3H. A quantitative intrinsic superacidity scale for the sulfonic acids XSO3H (X = HO, F, and CF3)

Cited by 119 publications

References 1 publication

Gas-Phase Acidities of Nine Sulfur Oxoacids of Composition [H2,S,On] (n = 1–4)

Gas-Phase Acidities of Nine Sulfur Oxoacids of Composition [H2,S,On] (n = 1–4)

Anchor Points for the Unified Brønsted Acidity Scale: The rCCC Model for the Calculation of Standard Gibbs Energies of Proton Solvation in Eleven Representative Liquid Media

Brønsted Acidity and the Medium: Fundamentals with a Focus on Ionic Liquids

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