Conformations of Glycolic Acid.

Jensen, Frank; Poulsen, F.W.; Nielsen, Kurt; Huuskonen, Juhani; Rissanen, Kari; Shi, Wenjun; Styring, Stenbjörn; Tommos, Cecilia; Warncke, Kurt; Wood, Bryan R.

doi:10.3891/acta.chem.scand.51-0439

Cited by 12 publications

(11 citation statements)

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“…In consonance with the literature data [12][13][14][15][16][17], the SSC conformer was predicted at all levels of calculation as the global energy minimum. The relative energies of the other forms at different calculation levels are summarized in Table 1.…”

Section: Resultssupporting

confidence: 83%

“…Hollenstein and collaborators [23,24] investigated the infrared spectra of several isotopologues of GA isolated in argon. Besides the dominant spectral features present in the freshly prepared matrix, ascribable to the most stable SSC conformer, they were able to observe, in the spectrum obtained after broadband infrared irradiation of the matrix, a series of new bands which were assigned to the third most stable conformer predicted theoretically [13,14,23,24]. Surprisingly, the presence in the matrix samples of a third conformational structure was not deduced.…”

Section: Introductionmentioning

confidence: 80%

“…1), though in the crystal intermolecular interactions lead to deviation of the alcoholic OH group a few degrees from the plane of the CC(@O)OH fragment. Theoretical calculations undertaken at different levels of theory [11][12][13][14][15][16][17] also predict the SSC conformer as the conformational ground state for monomeric GA.…”

Section: Introductionmentioning

confidence: 99%

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First experimental evidence of the third conformer of glycolic acid: combined matrix isolation, FTIR and theoretical study

Reva

Jarmelo

Lapiński

et al. 2004

Chemical Physics Letters

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The FT-IR spectra of monomeric glycolic acid, GA, isolated in argon and xenon matrices (at 10 and 20 K) were studied, enabling identification of three different conformers of GA. The most stable SSC conformer involves a hydrogen bond between the carbonyl group and the hydrogen atom of the alcohol hydroxyl group. The minor GAC and AAT forms involve intramolecular hydrogen bonds between alcohol and carboxyl OH groups, with alcohol and carboxylic groups serving as proton donors, respectively. The GAC conformer, predicted by theoretical calculations (at the DFT/B3LYP and MP2 levels with the 6-31++G(d,p) and aug-cc-pVDZ basis sets) as the second most stable form, was now experimentally identified for the first time.

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Section: Resultssupporting

confidence: 83%

Section: Introductionmentioning

confidence: 80%

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First experimental evidence of the third conformer of glycolic acid: combined matrix isolation, FTIR and theoretical study

Reva

Jarmelo

Lapiński

et al. 2004

Chemical Physics Letters

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“…This latter compound is by far the most studied member of the family, both experimentally and theoretically. [4][5][6][7][8][9][10][11] From 1977 to the present, several calculations have been carried out on glycolic acid at several levels of approximation, indicating that its most stable conformer is the intramolecularly hydrogen bonded form showing all the HOCC, O=CCO and O=COH angles equal to 0 (SsC; 4,9,12 ).…”

Section: Introductionmentioning

confidence: 99%

Rotational isomers of lactic acid: first experimental observation of higher energy forms

Borba

Gómez‐Zavaglia

Lapiński

et al. 2004

Phys. Chem. Chem. Phys.

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Lactic acid {2-hydroxypropionic acid [CH(CH 3)OHCOOH]} monomer was studied by matrix isolation FT-IR spectroscopy and molecular orbital calculations undertaken at both DFT(B3LYP)/6-311þþG(d,p) and MP2/ 6-31G(d,p) levels of approximation. The theoretical calculations predicted the conformer (SsC) with the carboxylic group and both the CCOH (alcohol) and O=CCO moieties in a cis configuration as the most stable form. In this conformer, the a-hydroxy hydrogen atom is involved in an intramolecular hydrogen bond with the carbonyl oxygen atom. The second most stable conformer (GskC) also shows a cis carboxylic group and differs from SsC in the CCOH (alcohol) and O=CCO dihedral angles, which are equal to 43.3 and 156.8 respectively. These angles are equal to À51.5 and À149.9 in the third most stable conformer (G 0 sk 0 C). These forms are characterized by showing a relatively weak intramolecular H (alcohol) Á Á ÁO (acid) hydrogen bond. In the AaT conformer, the carboxylic group is trans and the CCOH (alcohol) and O=CCO dihedral angles are 162.2 and 174.1 , respectively. This conformer shows a relatively strong H (acid) Á Á ÁO (alcohol) hydrogen bond. In consonance with the theoretical results, the matrix isolation experiments confirmed the predominance of conformer SsC in argon and xenon matrices, and provide the first experimental evidence of conformers GskC and AaT. Since the barrier for interconversion G 0 sk 0 C $ GskC is only $2 kJ mol À1 , these two conformers are in equilibrium in the matrices and, at low temperature, the population of the less stable G 0 sk 0 C form is too small to enable its observation. Full assignment of the observed spectra was undertaken on the basis of comparison with the theoretical data and temperature variation studies. Water doping of matrices enabled the identification of spectral features due to weakly bound complexes of lactic acid with water.

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“…Four of the five lowest-energy rotamers are shown in Fig. 16 The most stable rotamer, G in Fig. The G rotamer is the most stable, the T rotamer lies about 2.7 kcal/ mol above G, the U rotamer and its near-degenerate partner UЈ lie about 3.2 kcal/ mol above G, and the V rotamer is about 1.2 kcal/ mol higher still.…”

Section: Introductionmentioning

confidence: 99%

Clusters of glycolic acid with three to six water molecules

Roy

Hu²,

Thakkar³

2005

The Journal of Chemical Physics

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Semiempirical, ab initio, and density functional theory calculations are used to locate many low-energy minima on the potential energy surfaces of the CH2OHCOOH-(H2O)n complexes with n = 3,4,5,6. In the clusters with three, four, and five water molecules, the lowest-energy structure consists of a (H2O)n complex, not necessarily of lowest energy, hydrogen bonded to the carboxylic group of the glycolic acid. The lowest-energy structure for n = 6 is similar except that the water hexamer is hydrogen bonded to both the carboxylic and alpha-hydroxyl groups of the acid. In all the lowest-energy clusters, the intramolecular hydrogen bond remains intact in the glycolic acid.

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Conformations of Glycolic Acid.

Cited by 12 publications

References 0 publications

First experimental evidence of the third conformer of glycolic acid: combined matrix isolation, FTIR and theoretical study

First experimental evidence of the third conformer of glycolic acid: combined matrix isolation, FTIR and theoretical study

Rotational isomers of lactic acid: first experimental observation of higher energy forms

Clusters of glycolic acid with three to six water molecules

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