Gas Phase Basicities and Proton Affinities

An updated compilation of gas-phase basicities and proton affinities has been published (98MI3). 

Hunter, E. P. L. Lias, S. Evaluated gas phase basicities and proton affinities of molecules An update. I. Phys. Chem. Ref. Data 1998,27,413-457. 

In the first place, this chapter deals with the fundamentals of gas phase ion chemistry, i.e., with ionization, excitation, ion thermochemistry, ion lifetimes, and reaction rates of ion dissociation. The final sections are devoted to more practical aspects of gas phase ion chemistry such as the determination of ionization and appearance energies or of gas phase basicities and proton affinities. 

Lias, S.G. Liebman, J.F. Levin, R.D. Evaluated Gas Phase Basicities and Proton Affinities of Molecules Heats of Formation of Protonated Molecules. J. Phys. Chem. Ref Data 1984, 75,695-808. 

The influence of cyclopropyl on the gas phase stability of carbocations as measured by ion cyclotron resonance is shown in Table 14, along with data for some reference compounds. The results are given as gas phase basicities, GB, and proton affinities, PA, defined as AG° and AH°, respectively, for dissociation of the protonated molecule, as in equation 11. In addition hydride affinities D(BH H ) for some cations defined as — AH° for equation 18 are included. For the gas phase basicities and proton affinities the products B are alkenes, amines, nitriles or carbonyl compounds, and thus for these values the stability of the cation is compared to a derivative where the substituent is conjugated with a carbon-carbon or carbon-oxygen double bond, or a nitrogen lone pair, whereas for hydride affinities the products are saturated. 

The gas phase basicity and proton affinity are intimately related entities being defined by the same hypothetical reaction ... 

Data Compilations. Gas Phase Basicities and Proton Affinities. 

TABLE 6.6 Gas-Phase Basicity and Proton Affinities for Nitrogen Bases... 

E. P. L. Hunter, S. G. Lias., Evaluated gas phase basicities and proton affinities of molecules An Update. J. Phys. Chem. Rtf. Data, 1998, 27,413 E. P. L. Hunter, S. G. Lias., Proton Affinity and Basicity Data, in NIST Chemistry Web Book, Standard Reference Database, 2005, No. 69 (eds W. G. MaUard and P. J. Linstrom), National Institutes of Standards and Technology, Gaithersburg, MD (http // webbook.nisLgov/chemistry, accessed May 2012). 

A.G. Harrison, Gas-phase basicities and proton affinities of amino acids and peptides, Mass Spectrom. Rev. 16 (1997), pp. 201-217. 

Harrison, A. (1997) The Gas-phase Basicities and Proton Affinities of Amino Acids and Peptides. Mass Spectrom. Rev. 16 201-217. 

Lias SG, Liebman JF, Levin RD (1984) Evaluated gas phase basicities and proton affinities of molecules heats of formation of protonated molecules. J Phys Chem Ref Data 13 695. doi 10.1063/1.555719... 

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