Premium
A computational evaluation of the steric and electronic contributions to the stability of the structures of α− and β−D‐glucopyanose Part 2: natural bond orbital analysis of monosubstituted cyclohexanes and pyrans (593.3)
Author(s) -
Baello Rofe,
Abdulsalam Maryam,
Balilli Rahih,
Brutofsky Christian,
Kasner Marc
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.593.3
Subject(s) - natural bond orbital , steric effects , cyclohexanes , chemistry , substituent , computational chemistry , electronic effect , ring (chemistry) , electronic structure , molecule , density functional theory , bond length , stereochemistry , crystallography , organic chemistry
The anomeric effect refers to the tendency of an electronegative substituent at C2 in a pyran to be lower in energy when in the axial orientation than in the equatorial orientation. By examining the geometric and electronic parameters of a sequence of monosubstituted tetrahydro‐2H‐pyrans (‐CH3 ‐OH and ‐CH2OH) and comparing them to a set of similarly substituted cyclohexanes the steric factors can be evaluated and the magnitude of the electronic interaction can be evaluated. The changes in the bond lengths and bond angles that occur when an oxygen is substituted for a CH2 in the pairs of molecules (cyclohexanes versus the pyrans) show that steric interactions cannot explain all the structural stabilities and energies. Natural Bond Orbital analysis shows that donation of electron density from the ring oxygen occurs in all three pyrans) but, as expected, is most significant in 2‐hydroxyl tetrahydro‐2H‐pyran. There appears to be little or no donation of electron density is the substituted cyclohexanes . Recognizing that the cyclic configuration of glucopyranose is a substituted tetrahydro‐2H‐pyran and that the ‐CH2OH substituent plays a major role in determining the energetic stability of the compound, analysis of this series of compounds can determine the significance of many of the electronic interaction in glucopyranose . The NBO analysis helps to quantify the details of the electronic interactions that contribute to the geometrical structure of α− and β−D‐glucopyranose.