Epimeric and anomeric relationship of octyl- α - d -gluco/galactosides: Insight from density functional theory and atom in molecules studies

Ahmadi, Sara; Manickam-Achari, Vijayan; Hussain, Zahir; Hashim, Roslan

doi:10.1016/j.comptc.2017.03.023

Cited by 11 publications

(10 citation statements)

References 45 publications

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“…Mannose and galactose are important natural products mainly found in plant sources, , and they both are C-2 and C-4 epimers of glucose, respectively, where the OH group is axially positioned at C-2 in the former and at C-4 in the latter. From density functional theory calculations, the intramolecular HBs of these epimerically related glycolipids define conventional HBs which were reported to be more stable than the nonconventional ones. , α-Man-OC 8 , with two conventional HBs, is more stable and has a higher T C value than α-Glc-OC 8 . On the other hand, the galactoside with an axial OH on C-4 has only one conventional intramolecular HB and subsequently has the smallest T C value .…”

Section: Resultsmentioning

confidence: 99%

“…From density functional theory calculations, the intramolecular HBs of these epimerically related glycolipids define conventional HBs which were reported to be more stable than the nonconventional ones. , α-Man-OC 8 , with two conventional HBs, is more stable and has a higher T C value than α-Glc-OC 8 . On the other hand, the galactoside with an axial OH on C-4 has only one conventional intramolecular HB and subsequently has the smallest T C value . Thus, the clearing temperature of these epimers is in the following order: T C (α-Man-OC 8 ) > T C (α-Glc-OC 8 ) > T C (α-Gal-OC 8 ).…”

Section: Resultsmentioning

confidence: 99%

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Probing n-Octyl α-d-Glycosides Using Deuterated Water in the Lyotropic Phase by Deuterium NMR

et al. 2021

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The lyotropic phase behavior of four common and easily accessible glycosides, n-octyl α-D-glycosides, namely, α-Glc-OC 8 , α-Man-OC 8 , α-Gal-OC 8 , and α-Xyl-OC 8 , was investigated. The presence of normal hexagonal (H I ), bicontinuous cubic (V I ), and lamellar (L α ) phases in α-Glc-OC 8 and α-Man-OC 8 including their phase diagrams in water reported previously was verified by deuterium nuclear magnetic resonance ( 2 H NMR), via monitoring the D 2 O spectra. Additionally, the partial binary phase diagrams and the liquid crystal structures formed by α-Gal-OC 8 and α-Xyl-OC 8 in D 2 O were constructed and confirmed using small-and wide-angle X-ray scattering and 2 H NMR. The average number of bound water molecules (n b ) per headgroup in the L α phase was determined by the systematic measurement of the quadrupolar splitting of D 2 O over a wide range of molar ratio values (glycoside/ D 2 O), especially at high glucoside composition. The number of bound water molecules bound to the headgroup was found to be around 1.5−2.0 for glucoside, mannoside, and galactoside, all of which possesses four OH groups. In the case of xyloside, which has only three OH groups, the bound water content is ∼2.0. Our findings confirmed that the bound water content of all n-octyl α-Dglycosides studied is lower compared to the number of possible hydrogen bonding sites possibly due to the fact that most of the OH groups are involved in intralayer interaction that holds the lipid assembly together.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Probing n-Octyl α-d-Glycosides Using Deuterated Water in the Lyotropic Phase by Deuterium NMR

et al. 2021

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“…From Table 3, the cis-pair have T C s nearly similar and, moreover, their T C s are much higher than those of the trans-pair. Modeling studies on various octyl glycosides and simulations support this hypothesis 20,78 , by relating intralayer hydrogen bondings to the stability of the self-assembly. Although this trend in the T C s was first observed for the Guerbet glycosides see above since many such quartets were examined systematically 26 , this trend is markedly noticeable in α/β-GalC 18 and α/β-GlcC 18 , prepared by Hori et al in 1959 12 .…”

Section: Epimer and Anomer Relationshipmentioning

confidence: 75%

Dry Thermotropic Glycolipid Self-Assembly:A Review

et al. 2018

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“…The anomeric effect isoccurred when two electronegative substituents are attached to a sp 3 -hybridized carbon atom. Many theoretical investigations have assessed the anomeric effect [19][20][21][22][23][24][25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Conformational Analysis of 2-halo-1,3,2-dioxaphosphinanes: A Density Functional Theory (DFT) Investigation

2020

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This research aimed at evaluating the stability of the 2-halo-1,3,2dioxaphosphinanes conformers at the LC-BLYP/aug-cc-pVTZ level of theory. The estimation of the total energy and the dipole moments of the axial and equatorial conformations were first done for the aforementioned molecules. Intermediate states of the transformations of the axial to equatorial conformer were determined. In the basis of the calculations, the axial conformer was found to be more stable than the equatorial conformer in these molecules. Transition states of these transformations were studied, as well. IN addition, the energetic and thermodynamics parameters of these transformations were investigated. Change of the P=O bond distances were illustrated with endo and exo-anomeric effects. The comparison of the P-O bond distances indicated the shorter bonds in the axial conformer compared to the equatorial conformer. These changes attributed to a dominant LP (2)O  σ* (P-X) negative hyperconjugation interaction between a pair of non-bonded electrons on oxygen and the adjacent P-X bond in axial conformer. The partitioning of the total electronic energy E(tot) into Lewis E(L) and non-Lewis E(NL) parts was performed using the concept of the natural bond orbital (NBO) analysis. Then, the natural coulomb electrostatic (NCE) potential energies, total energies into Lewis components, and total steric exchange energies were estimated. Calculations revealed that axial conformer was more stable than the equatorial conformer in the studied molecules. In addition, the barrier energy values of the transformations of axialboatequatorial conformers enhanced with decreasing the electronegativity of halogen. KEYWORDS 2-Halo-1,3,2-dioxaphosphinanes Anomeric effect Conformers Natural bond orbital analysis

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Epimeric and anomeric relationship of octyl- α - d -gluco/galactosides: Insight from density functional theory and atom in molecules studies

Cited by 11 publications

References 45 publications

Probing n-Octyl α-d-Glycosides Using Deuterated Water in the Lyotropic Phase by Deuterium NMR

Probing n-Octyl α-d-Glycosides Using Deuterated Water in the Lyotropic Phase by Deuterium NMR

Dry Thermotropic Glycolipid Self-Assembly:A Review

Conformational Analysis of 2-halo-1,3,2-dioxaphosphinanes: A Density Functional Theory (DFT) Investigation

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