Abstract
For the relationship between thermodynamic parameters, global hardness, global electronegativity, anomeric effect, structural parameters, and structural properties of dodecahedro-spiro [isochromene-3,2'-pyran] (A), dodecahedro-spiro [isothiocromene-3,2'- thiopyran) (B), dodecahedro-spiro [isochroman-3,2'-thiopyran] (C) and dodecahedro-spiro [isothiochrome-3,2'-pyran] (D) computational methods (B3LYP / 6-311 ++ G **) were used. Results show that the calculated Gibbs free energy and enthalpy differences between the axial- and equatorial- stereoisomers [i.e. ΔG = Geq – Gax, ΔH = Heq- Hax] decrease from compound A to compound B and from compound C to compound D. NBO results show that the anomeric effect associated with the electron delocalization is in benefit of the axial-stereoisomers and with the decrease of the anomeric effect, the values of global hardness (η), and global electronegativity (χ), from compound A to compound B and from compound C to Composition D is also decrease. The correlations between the global hardness, global electronegativity, anomeric effect, structural parameters, and thermodynamic parameters [ΔH, ΔG, and ΔS] of compounds A-D have been investigated. Also, it can be concluded that the stability energy obtained from the numerical values of the anomeric effect and the values calculated theoretically (B3LYP / 6-311 ++ G **) confirmed each other.
Publisher
Romanian Academy - Revue Roumaine De Chimie
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