University of May 8th

Guelma, Algeria

University of May 8th

Guelma, Algeria
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Bensouilah N.,University of Science and Technology Houari Boumediene | Bensouilah N.,University of May 8th | Fisli H.,University of May 8th | Bensouilah H.,May 8th 1945 University | And 3 more authors.
Journal of Molecular Structure | Year: 2017

In this work, the inclusion complex of DCY/CENS: N-(2-chloroethyl), N-nitroso, N′, N′-dicyclohexylsulfamid and β-cyclodextrin (β-CD) is investigated using the fluorescence spectroscopy, PM3, ONIOM2 and DFT methods. The experimental part reveals that DCY/CENS forms a 1:1 stoichiometric ratio inclusion complex with β-CD. The constant of stability is evaluated using the Benesi-Hildebrand equation. The results of the theoretical optimization showed that the lipophilic fraction of molecule (cyclohexyl group) is inside of β-CD. Accordingly, the Nitroso-Chloroethyl moiety is situated outside the cavity of the macromolecule host. The favorable structure of the optimized complex indicates the existence of weak intermolecular hydrogen bonds and the most important van der Waals (vdW) interactions which are studied on the basis of Natural Bonding Orbital (NBO) analysis. The NBO is employed to compute the electronic donor–acceptor exchanges between drug and β-CD. Furthermore, a detailed topological charge density analysis based on the quantum theory of atoms in molecules (QTAIM), has been accomplished on the most favorable complex using B3LYP/6-31G(d) method. The presence of stabilizing intermolecular hydrogen bonds and van der Waals interactions in the most favorable complex is predicted. Also, the energies of these interactions are estimated with Espinosa's formula. The findings of this investigation reveal that the correlation between the structural parameters and the electronic density is good. Finally, and based on DFT calculations, the reactivity of the interesting molecule in free state was studied and compared with that in the complexed state using chemical potential, global hardness, global softness, electronegativity, electrophilicity and local reactivity descriptors. © 2017 Elsevier B.V.

Nessaib M.,University of May 8th | Djahoudi A.,Annaba University | Seridi A.,University of May 8th | Seridi A.,Skikda University | And 4 more authors.
Heterocycles | Year: 2011

The synthesis of a new series of TV-substituted perhydro-1,3-oxazin-2-ones containing V-phenylsulfonamide is described. The compounds 7a-7f were obtained in a one-pot reaction from chlorosulfonyl isocyanate, selected 1, 3-halogenoalcohols and various aromatic amines in alkaline conditions, to give the target N-heterocyclic 6-membered ring compounds with good yields. The X-ray crystal structure of N-[(N-4-fluorophenyl)sulfamoyl]perhydro-1, 3-oxazin-2-one 7d was solved. All the synthesized compounds have been screened for their invitro antibacterial activity against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. Structures of 7d and 6e can be further optimized to give new potent antibacterial agents with structures significantly different from those of existing classes of antibiotics. © The Japan Institute of Heterocyclic Chemistry.

Bensouilah N.,University of May 8th | Abdaoui M.,University of May 8th
Comptes Rendus Chimie | Year: 2012

The inclusion complex of N-nitroso, N-(2-chloroethyl), N′, N′-dibenzylsulfamid with β-Cyclodextrin have been investigated using the spectrofluorescence technique 1H NMR spectroscopy. The stoichiometric ratio of the complex was found to be 1:1 and the stability constant was evaluated using the Benesi-Hildebrand equation. In order to find the most favorable structure, molecular mechanics calculations were employed to study the inclusion of CENS-Dibenz in β-CD in vacuum and in the presence of water as a solvent. The driving forces for complexation are dominated by non-bonded van der Waals host-guest interactions with very little electrostatic contribution in both environments. After this stage of calculation, both the most stable complexes obtained by MM+ were re-optimized using semi-empirical and quantum mechanical calculations. It was found that the PM3 and the hybrid method ONIOM2 calculations predict the same mode of inclusion of the drug molecule in the host cavity. In the most stable conformation (i.e. Complex A), one of the two aromatic cycles is dipped within the relatively less polar cavity of β-cyclodextrin, while the other aromatic cycle as well as the active groupings (alkylating agent and nitroso group) are directed towards the exterior through the narrow rim of β-CD. This orientation is preferred because it is the most energetically favorable structure. Moreover, statistical thermodynamic calculations demonstrate that the formation of the inclusion complex is an enthalpy-driven process. A comparison between the experimental and theoretical values of ΔG 0 proves that simulation of the complexes without an explicit treatment of the solvent leads to dubious results. © 2012 Académie des sciences. Published by Elsevier Masson SAS. All rights reserved.

Mohamdi M.,University of May 8th | Bensouilah N.,University of May 8th | Abdaoui M.,University of May 8th
Journal of Theoretical and Computational Chemistry | Year: 2016

Two novel charge transfer complexes CTC ([D→TCNE] and [D→CHL]: D = (S, S)-bis-N,N-sulfonyl bis-L-phenylalanine dimethylester; TCNE = Tetracyanoethylene; CHL = Chloranil) were synthesized and characterized by elemental analysis: Electronic absorption, spectrophotometric titration, IR. The obtained results indicate the formation of 1:1 for both complexes. The experimental studies were complemented by quantum chemical calculations at DFT/CAM-B3LYP level of theory. Optimized geometrical structures, the electronic spectroscopy, excited-state properties and the descriptions of frontier molecular orbitals were computed and discussed by time-dependent density functional theory (TD-DFT). In addition, vibrational frequency calculations, the natural population analysis (NPA) confirms the presence of intermolecular interactions and natural bonding orbitals (NBO) calculation was carried out in order to elucidate the interactions between TCNE π-acceptor and donor molecule. © 2016 World Scientific Publishing Company.

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