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Structural analysis and IR-spectroscopy of a new Anilinium hydrogenselenite hybrid compound: a subtle structural phase transition
(Inorganica Chimica Acta, 2016) Takouachet, Radhwane; Benali-Cherif, Rim; Bendeif, El-Eulmi; Benali-Cherif, Nourredine; Pillet, Sébastien; Schaniel, Dominik
An interesting structural behaviour has been detected and characterized in a new anilinium based compound by single crystal X-ray diffraction measurements and infrared spectroscopy. The temperature dependent structural investigation reveals that the studied compound undergoes a subtle non-centrosymmetric to centrosymmetric structural phase transition. At room temperature the crystal structure is non-centrosymmetric and is characterized by an important disorder in the organic part where the independent aromatic rings are rotated around the C1—C4 and C7—C10 molecular axis by 52.06(6) and 56.25(4)° respectively. By decreasing the temperature to 100 K the organic cation is less disordered and the rotation angle of the aromatic rings changes to 54.73(2)°. As a consequence, the low temperature structure becomes centrosymmetric. The infrared spectra recorded on cooling and heating the sample in the temperature range of 300-9 K support this analysis. The ammonium group (NH3) is significantly affected by the temperature change. This effect results, when cooling the sample below 140K, in the appearance of a new vibrational band corresponding to the (NH3)-wagging modes at 705 cm-1. The phenomenon is completely reversible and the new vibrational band disappears upon heating the sample above 140K. Moreover, the ν(C-N)-stretching and the (NH3)-scissoring modes are also affected by the temperature variation as can be seen in the spectral ranges of 1250–1400 cm−1 and 1610–1635 cm−1 respectively. The spectroscopic results are complementary to the structural analysis and indicate that the structural phase transition is correlated with the molecular rotation of the aromatic moieties around the C1—C4 axis that affect the different vibrational modes of the ammonium group.
Synthesis, structural elucidation, spectroscopic, Hirshfeld surface analysis and theoretical simulation of a new adeninium orthoperiodate (1-) bis(hydrate) organic-inorganic hybrid crystals
(Journal of Molecular Structure, 2020-08-17) Benali-Cherif, Rim; Takouachet, Radhwane; Falek, Wahiba; Benali-Cherif,Nourredine; Jelsch,Christian; Merazig, Hocine; Hafied, Meriem; Bendeif,El-Eulmi; Mokhnachi, Naima Bouslah; Taibi,Kamel
One novel organic-inorganic hybrid supramolecular compound named Adeninium orthoperiodate (1-) bis(hydrate) (I) has been synthesized and characterized by FT-IR spectroscopy and single-crystal X-ray diffraction complemented with a quantum chemical study performed with DFT method at the B3LYP/3-21G level. The title compound crystallized in the monoclinic centrosymmetric P 21/n space group. In the molecular arrangement, the different entities are held together through the interplay of intermolecular O-H...N/O and N-H...O hydrogen bonds, that found to be effective in stabilizing the three-dimensional crystal packing
Crystal engineering of a new pharmaceutical polymorph of Gallic acid monohydrate: A structural comparative study and chemical computational quantum investigations
(Royal Society of Chemistry, 2023-11) Ghouari, Nasreddine; Benali-Cherif, Rim; Takouachet, Radhwane; Falek,Wahiba; Missaoui, Djallila; Rahmouni,Ali; Bendeif, El-Eulmi; Benali-Cherif, Nourredine
This study reports the synthesis, crystal structure, and theoretical characterization of a novel, seventh pharmaceutical polymorph of Gallic acid monohydrate (GAM-VII). Single-crystal X-ray diffraction at 100 K reveals that GAM-VII crystallizes in the triclinic $P\bar{1}$ space group, featuring a unique disordered water molecule ($\text{O2W}$) that forms extensive hydrogen-bonding networks and bridges adjacent layers. Within the crystal lattice, Gallic acid molecules adopt a syn $\text{COOH}$ orientation to form centrosymmetric $(\text{COOH})_2$ dimers with an $R_2^2(8)$ motif, while Hirshfeld surface analysis confirms that $O-H\cdots O$ hydrogen bonds and $\pi\cdots\pi$ stacking interactions primarily drive the 3D structural stabilization. Furthermore, quantum chemical computations show that GAM-VII possesses the highest dipole moment among all known GAM polymorphs, highlighting strong polar interactions that enhance its overall stability and demonstrating the crucial role of water molecules as design elements in crystal engineering for active pharmaceutical ingredients (APIs).
1st Year Medicine - Physics-Biophysics Exam (With Answer Key)
(FACULTY OF MEDICINE ANNEX- ABBES LAGHROUR UNIVERSITY , KHENCHELA, 2026-06-04)
1st Year Medicine - 2nd Written Examination in Human Anatomy (Lower Limb) with Answer Key
(FACULTY OF MEDICINE ANNEX- ABBES LAGHROUR UNIVERSITY , KHENCHELA, 2026-06-02)