Browsing by Author "Abdelazize Bouhadiba"

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Host-guest inclusion complex between b-cyclodextrin and paeonol: A theoretical approach
(2013) Sakina Haiahem; Leila Nouar; Imen Djilani; Abdelazize Bouhadiba; Fatiha Madi; Djamel Eddine Khatmi
Host-guest interactions of b-cyclodextrin (b-CD) with paeonol (PAE) were simulated using semi-empirical PM3 and both ONIOM2 [(B3LYP/6-31G*:PM3), (HF/6-31G*:PM3)] methods. The results obtained with PM3 method clearly indicate that the complexes formed are energetically favored with or without solvent, the model 1 (PAE entering into the cavity of b-CD from its wide side by OCH3 group) is found more favored than the model 2 (PAE entering into the cavity of b-CD from its wide side by COCH3 group). Finally, natural bonding orbital (NBO) analysis was performed based on ONIOM2 optimized complexes to quantify the donor–acceptor interactions between PAE and b-CD.
Molecular modeling investigation of para-nitrobenzoic acid interaction in β-cyclodextrin
(2011) Leila Nouar; Sakina Haiahem; Abdelazize Bouhadiba; Fatiha Madi; Leila Lagrate
Geometry optimizations of para-nitrobenzoic acid (PNBA)/β-cyclodextrin complex were carried out using MM+, PM3 and density function theory B3LYP/6-31G*. Calculations were performed upon the inclusion complexation of β-cyclodextrin (CD) with neutral (PNBA1) and anionic (PNBA2) species of para-nitrobenzoic acid. The results obtained from both methods consistently indicate that the complex of PNBA2/β-CD (B) is significantly more favorable than the others energetically. The negative enthalpy changes calculated from the statistical thermodynamic calculation suggest that both the inclusion complexation is favored enthalpy-driven process. The geometry of the most stable complex shows that the aromatic ring is deeply self-included inside the hydrophobic cavity of β-CD and also intermolecular hydrogen bonds were established between host and guest molecules. This suggests that hydrophobic effect and hydrogen bond play an important role in the complexation process.
Molecular modeling investigation of para-nitrobenzoic acid interaction in β-cyclodextrin
(2011) Leila Nouar; Sakina Haiahem; Abdelazize Bouhadiba; Fatiha Madi; Leila Lagrate
Geometry optimizations of para-nitrobenzoic acid (PNBA)/β-cyclodextrin complex were carried out using MM+, PM3 and density function theory B3LYP/6-31G*. Calculations were performed upon the inclusion complexation of β-cyclodextrin (CD) with neutral (PNBA1) and anionic (PNBA2) species of para-nitrobenzoic acid. The results obtained from both methods consistently indicate that the complex of PNBA2/β-CD (B) is significantly more favorable than the others energetically. The negative enthalpy changes calculated from the statistical thermodynamic calculation suggest that both the inclusion complexation is favored enthalpy-driven process. The geometry of the most stable complex shows that the aromatic ring is deeply self-included inside the hydrophobic cavity of β-CD and also intermolecular hydrogen bonds were established between host and guest molecules. This suggests that hydrophobic effect and hydrogen bond play an important role in the complexation process.