Journal Articles
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Item Theoretical study of the inclusion processes of the phenylurea herbicide metobromuron in β-cyclodextrin.(ANSInet, Asian Network for Scientific Information, 2011) Leila Nouar; Sakina Haiahem; Abdelaziz Bouhadiba; Fatiha Madi; Leila Largate; Fateh DjeblouneWe investigated the inclusion process of phenylurea herbicide metobromuron (MB) in beta cyclodextrin (β-CD) with 1:1 stoichiometry using: (1) MM+ force field of molecular mechanics in order to research the lowest energy structure of the inclusion complex. (2) Superior levels of calculations were made such PM3, B3LYP/6-31G*, HF/6-31G* and ONIOM2 methods in order to approach the ideal geometry and provide further insight into the different complexation properties of the guest molecule. The data suggest that: The B orientation is significantly more favourable than the A orientation by an energy difference of 1.02 kcal mol-1 according to PM3 calculations. The geometry of the most stable complex shows that the aromatic ring is deeply self-included inside the hydrophobic cavity of β-CD also an intermolecular hydrogen bond is established between host and guest molecules. The formation of the inclusion complex is predicted to be an enthalpy-driven process in gas phase which is in accord with the experimental results. The statistical thermodynamic calculations by PM3 demonstrate that 1:1 MB/β-CD complex is favored by a negative enthalpy change.Item Theoretical investigation to characterize the inclusion complex of a-lipoic acid and b-cyclodextrin(2015) Imene Djilani; Fatiha Madi; Leila Nouar; Sakina Haiahem; Mohamed Rahim; Djamel Eddine Khatmi; Abdelaziz BouhadibaWe simulated the docking of a-lipoic acid (a-LA) in b-cyclodextrin (b-CD) using two models. We considered in this study complexes formed by 1:1 host–guest stoichiometry in vacuo and in aqueous phase, using PM6, DFT and ONIOM2 hybrid calculations. The results obtained with PM6 method clearly indicate that the complexes formed are energetically favored with or without solvent, model 2 (a-LA entering the cavity of b-CD from its wide side by COOH group) is found more favored than model 1 (a-LA entering into the cavity of b-CD from its wide side by cyclic group), the preference being greater in the case of ONIOM2 calculations. In addition, NBO analysis gives that mutual interactions between the donor and acceptor orbitals of a-lipoic acid and b-CD plays an important role to the stabilization of such a complex. Finally, 1H nuclear magnetic resonance (NMR) chemical shifts of free and complexed a-LA were calculated by the Gauge-Including Atomic Orbital (GIAO) method and compared with available experimental data. The results of GIAO calculations were analyzed and discussed.Item Molecular docking study on b-cyclodextrin Interactions of metobromuron and [3-(p-bromophenyl)-1-methoxy-1- methylurea](2012-03-04) sakina haiahem; Abdelaziz Bouhadiba; Leila Nouar; Imene Djilani; Fatiha Madi; Djamel Eddine KhatmiThe inclusion process involving b-cyclodextrin (b-cyclodextrin-CD) and phenylurea herbicide metobromuron (MB) has been investigated by using the MM?, PM3, B3LYP, HF, ONIOM2 and NBO methods. The binding and complexation energies for both orientations considered in this research are reported. The geometry of the most stable complex shows that the aromatic ring is deeply selfincluded inside the hydrophobic cavity of b-CD also an intermolecular hydrogen bond is established between hostand guest molecules. This suggests that hydrophobic effect and hydrogen bond play an important role in the complexation process. The statistical thermodynamic calculations by PM3 demonstrate that 1:1 MB/b-CD complex is favored by a negative enthalpy change. Moreover, NBO calculations proved also that are a very useful means to quantify the interaction energies of the hydrogen bonds.Item Theoretical investigation study based on PM3MM and ONIOM2 calculations of β-Cyclodextrin complexes with diphenylamine(2012) Abdelaziz Bouhadiba; Leila Nouar; Sakina Haiahem; Imene Djilani; Fatiha Madi; DjamelEddine KhatmiThe inclusion complex of b-cyclodextrin (b-CD) and diphenylamine (DPA) was investigated by using PM3MM, DFT, HF and ONIOM2 methods. The most stable structure was obtained at the optimum position and angle. The results indicate that the inclusion complex formed by DPA entering into the cavity of b-CD from its wide side (the secondary hydroxyl group side) is more stable than that formed by DPA entering into the cavity of b-CD from its narrow side (the primary hydroxyl group side). The structures show the presence of several intermolecular hydrogen bond interactions that were studied on the basis of natural bonding orbital (NBO) analysis, employed to quantify the donor–acceptor interactions between diphenylamine and b-CD. A study of these complexes in solution was carried out using the CPCM model to examine the influence of solvation on the stability of the diphenylamine b-CD complex.Item Inclusion complexes of ortho-anisidine and b-cyclodextrin: A quantum mechanical calculation(2013) Imene Djilani; Leila Nouar; Fatiha Madi; Sakina Haiahem; Abdelaziz Bouhadiba; DjamelEddine KhatmiThe structural aspects for the complexation of ortho-anisidine (O-AN)/b-cyclodextrin were explored by using PM6, density function theory B3LYP/6-31G*, M05-2X/6-31G*, B3PW91/6-31G*, MPW1PW91/6-31G*, HF/6-31G* methods and several combinations of ONIOM2 hybrid calculations. Calculations were performed upon the inclusion complexation of b-cyclodextrin (b-CD) with neutral (O-AN1) and cationic (O-AN2) species of ortho-anisidine. The obtained results with PM6 method clearly indicate that the formed complexes are energetically favored, the complex of O-AN2/b-CD in B orientation is significantly more favorable than the others energetically. The structures show the presence of several intermolecular hydrogen bond interactions that were studied on the basis of natural bonding orbital (NBO) analysis, employed to quantify the donor–acceptor interactions between ortho-anisidine and b-CD.Item Theoretical study of inclusion complexation of 3-amino-5-nitrobenzisothiazole with β-cyclodextrin(2011) Leila Nouar; Sakina Haiahem; Abdelaziz Bouhadiba; Fatiha MadiThe inclusion process involving β-cyclodextrin (β-CD) and 3-amino-5-nitrobenzisothiazole (ANBT) has been investigated by using the MM+ force field, AM1, PM3, HF and B3LYP theories. In this study we took into account only the stochiometry1:1. The complexation and interaction energies for both orientations considered in this research are reported. All quantum computational methods gave the A orientation as the most favorable in which the guest molecule is totally embedded in the hydrophobic cavity of the cyclodextrin with the NO2 group located near the primary hydroxyls of the β-CD and the NH2 group near the secondary hydroxyls with no hydrogen bonding formation. The negative complexation and interaction energies calculated suggest that the inclusion complexes are stable. HOMO and LUMO orbital investigations confirm the better stability of the A orientation.Item Theoretical study of inclusion complexation of 3-amino-5-nitrobenzisothiazole with β-cyclodextrin(2011) Leila Nouar; Sakina Haiahem; Abdelaziz Bouhadiba; Fatiha MadiThe inclusion process involving β-cyclodextrin (β-CD) and 3-amino-5-nitrobenzisothiazole (ANBT) has been investigated by using the MM+ force field, AM1, PM3, HF and B3LYP theories. In this study we took into account only the stochiometry1:1. The complexation and interaction energies for both orientations considered in this research are reported. All quantum computational methods gave the A orientation as the most favorable in which the guest molecule is totally embedded in the hydrophobic cavity of the cyclodextrin with the NO2 group located near the primary hydroxyls of the β-CD and the NH2 group near the secondary hydroxyls with no hydrogen bonding formation. The negative complexation and interaction energies calculated suggest that the inclusion complexes are stable. HOMO and LUMO orbital investigations confirm the better stability of the A orientation.