Mass spectrometer study of evaporation of .alpha.-amino acids

Gaffney, J. S.; Pierce, R. Christopher; Friedman, L.

doi:10.1021/ja00455a015

Cited by 102 publications

(49 citation statements)

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“…From these data, estimations of the energies of the different H-bonds present in DL-serine crystal and H-bond lengths were made using previously established empirical correlations [1,8,40,41], which compare well with available experimental structural and thermodynamical data. [18,42].…”

Section: Resultsmentioning

confidence: 99%

“…Sublimation enthalpy (DH sub ) is an important thermodynamic property of the condensed phase, useful for instance in studying polymorphism as well as molecular packing. The experimentally determined DH sub (by Langmuir evaporation technique [42]) for DL-serine crystal was 83.7 AE 4 kJ mol À1 . If the crystals were ''perfect'' and contained only the four different and ordered types of Hbonds determined by structural techniques, the sum of these four H-bond energies, i.e.…”

Section: Spectra/h-bond Distances and Spectra/h-bond Energies Correlamentioning

confidence: 93%

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Low-temperature infrared spectra and hydrogen bonding in polycrystalline dl-serine and deuterated derivatives

Jarmelo

Reva

Rozenberg

et al. 2006

Vibrational Spectroscopy

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The FT-IR spectra of polycrystalline DL-serine [a-amino-b-hydroxypropionic acid; HO-CH 2 -CH(NH 3 ) + -COO À ] and isotopically substituted [ND/OD Alcohol (<10% and >90% D); CD 2 (>98% D)] DL-serine were recorded in the range 4000-500 cm À1 in the temperature range 300-10 K, and fully assigned. The isotopic-doping/low-temperature methodology, which allows for decoupling of individual proton vibrational modes from the crystal bulk vibrations, was used to estimate the energies of the different H-bonds present in DL-serine crystal. To this end, the frequency shifts observed in both the NH/OH stretching and out-of-plane bending spectral regions (relatively to reference values for these vibrations in nonhydrogen-bonded DL-serine molecules) were used, together with previously developed empirical correlations. The results are compared with available structural data on this amino acid. #

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Section: Resultsmentioning

confidence: 99%

Section: Spectra/h-bond Distances and Spectra/h-bond Energies Correlamentioning

confidence: 93%

Low-temperature infrared spectra and hydrogen bonding in polycrystalline dl-serine and deuterated derivatives

Jarmelo

Reva

Rozenberg

et al. 2006

Vibrational Spectroscopy

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“…Amino acids have been the subject of a variety of experimental [1][2][3][4][5][6][7][8][9] and theoretical studies 10-68 because of its central role in metabolism as building blocks of proteins. Especially, among 20 amino acids, glycine has been usually preferred as a subject of theoretical studies due to its small size and the existence of experimental data.…”

Section: Introductionmentioning

confidence: 99%

“…Especially, among 20 amino acids, glycine has been usually preferred as a subject of theoretical studies due to its small size and the existence of experimental data. [1][2][3][4][5][6][7][8][9] High-level ab initio studies demonstrated that the neutral form (NE) of glycine exists in the gas phase but the zwitterionic form (ZW) is unstable in vacuo. [11][12][13][14][15][16][17][18][19][20]27,[30][31][32][33] However, as is well known, the ZW of glycine predominates in crystalline or in aqueous solution, 2 and hence the solvent (or environmental) effects should be included in the theoretical studies to explore the glycine chemistry correctly.…”

Section: Introductionmentioning

confidence: 99%

Comprehensive Studies on the Free Energies of Solvation and Conformers of Glycine: A Theoretical Study

Kim¹,

Park²,

Lee³

et al. 2011

Bulletin of the Korean Chemical Society

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The stable conformers of glycine and the inter-conversions between them were studied theoretically at various levels of theory, B3LYP, MP2, CCSD and CCSD(T), in the gas phase and in aqueous solution. In aqueous solution, the structures examined by use of the conductor-like polarizable continuum model (CPCM) with various cavity models, UA0, UAHF, UAKS, UFF, BONDI and PAULING, and by use of a discrete/continuum solvation model with eight water clusters. The Gibbs free energy differences between the neutral (NE) and zwitterionic conformers (ZW), ΔG Z-N [= G ZW -G NE ], in aqueous solution were well reproduced by using the BONDI and PAULING cavity models. However the ΔG Z-N values were underestimated in other cavity models, although the ZW conformers existed as stable species in aqueous solution. In the studies of a discrete/ continuum solvation model with eight water clusters, gas phase results are still insufficient to reproduce the experimental findings. However the ΔG Z-N values calculated by use of CPCM method in aqueous solution agreed well with the experimental ones.

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“…As suggested above, the Onsager model stabilizes the N cluster more than the Z cluster due to the larger N͑H 2 O͒ 8 dipole moment. 24 Although the IPCM model takes into account only the electrostatic part of the solvation free energy, these results suggest that the combination of a small number of explicit waters and a sophisticated continuum model will be an effective tool for the study of N-Z equilibria.…”

Section: Effects Of the Continuummentioning

confidence: 99%

A combined discrete/continuum solvation model: Application to glycine

Bandyopadhyay

Gordon

2000

The Journal of Chemical Physics

126

109

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A new solvation model that combines discrete and continuum descriptions of the solvent has been developed. The discrete solvent molecules are represented by effective fragment potentials (EFP), while the continuum is represented by the Onsager model. This (EFP+Onsager) model has been applied to the relative stabilities of the neutral and zwitterionic forms of glycine. Other supermolecule-continuum calculations were also performed, using quantum mechanical discrete waters and the isodensity polarizable continuum model (IPCM) or solvation model 5.42R (SM5.42R) for the continuum. It is shown that the Onsager model provides a poor description of the solvent in the supermolecule-continuum calculations. On the other hand, more sophisticated models can predict the correct energy order of the glycine isomers. Thus, the development of mixed methods that combine sophisticated continuum models with the discrete EFP model appear to be promising. Keywords Solvents, Polyelectrolytes Disciplines Chemistry CommentsThe A new solvation model that combines discrete and continuum descriptions of the solvent has been developed. The discrete solvent molecules are represented by effective fragment potentials ͑EFP͒, while the continuum is represented by the Onsager model. This ͑EFPϩOnsager͒ model has been applied to the relative stabilities of the neutral and zwitterionic forms of glycine. Other supermolecule-continuum calculations were also performed, using quantum mechanical discrete waters and the isodensity polarizable continuum model ͑IPCM͒ or solvation model 5.42R ͑SM5.42R͒ for the continuum. It is shown that the Onsager model provides a poor description of the solvent in the supermolecule-continuum calculations. On the other hand, more sophisticated models can predict the correct energy order of the glycine isomers. Thus, the development of mixed methods that combine sophisticated continuum models with the discrete EFP model appear to be promising.

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Mass spectrometer study of evaporation of .alpha.-amino acids

Cited by 102 publications

References 0 publications

Low-temperature infrared spectra and hydrogen bonding in polycrystalline dl-serine and deuterated derivatives

Low-temperature infrared spectra and hydrogen bonding in polycrystalline dl-serine and deuterated derivatives

Comprehensive Studies on the Free Energies of Solvation and Conformers of Glycine: A Theoretical Study

A combined discrete/continuum solvation model: Application to glycine

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