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An experimental and theoretical study of the molecular structure of an organic arsenate templated by 4-aminopyridine, with the general formula (C5H7N2)(C5H8N2)[AsO4]·H2O ((4-APH)(4-APH2)[AsO4]·H2O), is presented. The optimized geometry, vibrational frequencies and various thermodynamic parameters of the title compound calculated using DFT methods are in agreement with the experimental values. The theoretical calculations were performed using density functional theory (DFT) method at B3LYP/6-311 + + G(d,p) basis set levels. A detailed interpretation of the IR and Raman spectra were reported. The thermodynamic functions (heat capacity, entropy, and enthalpy) from spectroscopic data by statistical methods were obtained for the range of temperature 100–1000 K. The molecular orbital calculations such as Natural Bond Orbitals (NBOs), AIM approach, HOMO-LUMO energy gap, Molecular electrostatic potential (MEP), NLO characteristic and Hirshfeld surface analysis were performed with the same DFT level. Electronic stability of the compound arising from hyper conjugative interactions and charge delocalization were investigated based on the natural bond orbital (NBO) analysis. The molecular docking simulation results showed an excellent agreement with the experimental findings and satisfactory support the antiviral effects, the druggability and pharmacokinetic properties of the compound.

International audience; Crystals of (H2AMP)2[FeIIIBr4]Br3, where AMP refers to the 2-(Ammoniomethyl)pyridinium ligand, have been successfully synthesized through redox chemistry and analyzed using X-ray crystallography. The new complex crystallizes as red needles in the monoclinic space group, P21/c, with eight formula weights in a unit cell of dimensions: a = 12.358 (13), b = 28.572 (3), c = 13.544 (14) Å and β=92.009(5) °. Analysis of absorption and reflectance data through the visible and near-infrared provide insight into the optical properties of the material. The structural data and the BVS (Bond Valence Sum) calculations are in agreement with the iron (III) oxidation. In this work, the experimental and theoretical study on molecular structure and vibrational spectral analysis of the new product has been reported. Theoretical calculations were performed by using density functional theory (DFT) at the B3LYP/LAN2DZ basis set levels. The electronic parameters such as frontier molecular orbital, electrostatic potential and HOMO-LUMO energy were calculated. Also, NLO were studied with the same level of DFT. The theoretical values show good agreement with experimental values. In addition, (H2AMP)2[FeIIIBr4]Br3 reveals broad absorption across the visible spectrum and an optical bandgap of 1.06 eV. Then the obtained material can be a promising eco-friendly light absorber in solar cell application. Finally, the thermal behavior of this material has been performed by TGA/DTA. In addition, two phase transitions at T1 = 108 °C and T2 = 170 °C were evidenced by DSC measurements.

The bidentate amine, 2-picolylamine [2-(aminomethyl) pyridine: AMP], and concentrated hydrobromic acid have been used to synthesize a CoII/CoIII mixed-valence complex. Single crystals of the new compound were grown by the slow evaporation solution process at room temperature. The title compound crystallizes in the monoclinic system, space group P21/n, with a = 14.624 (5) A, b = 10.302 (5) A, c = 23.743(5) A , β = 95.280(5)° and Z = 4. The crystal structure consists of three crystallographically independent bromide ions, one diprotonated AMP, one half water molecule and two crystallographically independent Cobalt(II) and Cobalt(III) ions: one has an octahedral geometry while the other is tetrahedrally coordinated. The crystal packing diagram reveals interesting non-covalent interactions involving N H···Br, O H···O and O H···Br hydrogen bonds, leading to the generation of 3D supramolecular architecture. The structural data, the BVS (Bond Valence Sum) calculations, the magnetic and the spectroscopic measurements are in agreement with a six-coordinate Cobalt(III) and four-coordinate Cobalt(II) mixed-valence complex. In this work, the experimental and theoretical study on molecular structure and vibrational spectral analysis of the new product has been reported. Theoretical calculations were performed by using density functional theory (DFT) at the B3LYP/LAN2DZ basis set levels. The electronic parameters such as frontier molecular orbitals, electrostatic potential and HOMO-LUMO energy were calculated. NLO and thermodynamic properties were studied. The theoretical values show good agreement with experimental values. Finally, thermal analysis and temperature dependent magnetic susceptibility measurements have been performed.

Single crystals of a new organic–inorganic hybrid compound, with the formula (4-APH)(4-APH 2)[AsO4]·H2 O, was synthesized at room temperature by slow evaporation method and characterized by X-ray diffraction at 150 K, DSC–TG measurements, FT-IR and Raman spectroscopies . The title salt, (C 5H7N2)(C5H8N2)[AsO4]·H2 O, contains mono and diprotonated 4-aminopyridine cations, an arsenate trianion and one water molecule. The diprotonated 4-ammoniumpyridinium dication [C 5H8N2]2+ is disordered over two positions with refined site occupancies of 0.73 and 0.27 however the monoprotonated 4-aminopyridinium cation [C5H7N2]+ is ordered. The 4-aminopyridinium rings are essentially planar and occur in stacks along b axis. In the crystal, the AsIII atom is coordinated by four O atoms in a slightly distorted tetrahedral geometry. The arsenate O atoms link the 4-aminopyridinium cations and water molecules into a three-dimensional network via intermolecular O–H···O and N–H···O hydrogen bonds . Additionally, in this structure, the different types and the nature of aromatic–aromatic interactions can distinguish between a stacked arrangement are parallel displaced and T-shaped conformation. Furthermore, the room temperature IR and Raman spectra of the title compound were recorded and analyzed. On the basis of detailed vibrational studies, the detailed assignment confirms the presence of the organic groups and the anionic entities. Besides, the thermal analysis studies have been performed, but no phase transition was found in the temperature range 298–625 K. Results from X-ray crystallography , Raman, IR spectroscopy and thermal analysis are combined to provide a description of the new organic arsenate monohydrate, (C 5H7N2)(C5H8N2)[AsO4]·H2O.

Single crystals of a new organic–inorganic hybrid compound (2-HAMP)2[CoBr4], (2-HAMP = 2-protonated aminopyridinium cation) was synthesized and characterized by X-Ray diffraction at room temperature, DTA–TG measurement, FT-IR and FT-Raman spectroscopies and optical absorption. Its crystal structure is a packing of alternated organic and inorganic layers parallel to (a, b) plane. The different components are connected by a network of N/C–H⋯Br hydrogen bonds and halogen⋯halogen interactions. These hydrogen bonds give notable vibrational effects. Theoretical calculations were performed using density functional theory (DFT) for studying the molecular structure, vibrational spectra and optical properties of the investigated molecule in the ground state. The optimized geometrical parameters obtained by DFT calculations are in good agreement with single crystal XRD data. The energy and oscillator strength calculated by Time-Dependent Density Functional Theory (TD-DFT) results complements with the experimental findings. The simulated spectra satisfactorily coincide with the experimental UV–Visible spectrum. The results show good consistent with the experiment and confirm the contribution of metal orbital to the HOMO–LUMO boundary. Thermal analysis studies indicate the presence of three phase transitions at 68, 125 and 172 °C, which are confirmed by X-ray powder diffraction as a function of temperature.

Single crystals of the new organic–inorganic compound (C5H8N3)2[CoBr4]·H2O were grown by hydrothermal technique and characterized by X-ray diffraction, infrared absorption, raman spectroscopy scattering, optical absorption and thermal analysis. The title compound belongs to the triclinic space group P 1 ¯ and in the crystal structure, the inorganic layers are built from tetrabromidocobaltate anions [CoBr4]2− and free water molecules, linked together by O–H⋯Br hydrogen bonds and halogen···halogen interactions. The organic cations are intercalated between the mineral layers via N–H⋯Br hydrogen bonds and form chains through π⋯π interactions. Theoretical calculations were performed using density functional theory with the B3LYP/LanL2DZ level for studying the molecular structure and vibrational spectra of the title compound. Good consistency is found between the calculated results and the experimental structure, IR and Raman spectra. The optical properties were investigated by optical absorption showing Ligand-to-Metal Charge-Transfer transitions in the visible region and organic related π−π* transitions in the UV region.

Single crystals of [(R)-C5H14N2][Cu(SO4)2(H2O)4]·2H2O (1) were grown through the slow evaporation of a solution containing H2SO4, (R)-C5H12N2 and CuSO4·5H2O. These crystals spontaneously transform to [(R)-C5H14N2]2[Cu(H2O)6](SO4)3 (2) over the course of four days at room temperature. The same single crystal on the same mounting was used for the determination of the structure of (1) and the unit cell determination of (2). A second single crystal of the transformed batch has served for the structural determination of (2). Compound 1 crystallizes in the noncentrosymmetric space group P21 (No. 4) and consists of trimeric [Cu(SO4)2(H2O)4]2− anions, [(R)-C5H14N2]2+ cations and occluded water molecules. Compound 2 crystallizes in P21212 (No. 18) and contains [Cu(H2O)6]2+ cations, [SO4]2− anions and occluded water molecules. The thermal decompositions of compounds 1 and 2 were studied by thermogravimetric analyses and temperature-dependent X-ray diffraction.

The vibrational properties of β-SnWO4 at center of the Brillouin zone are investigated by Raman at low temperature and infrared spectroscopies in connexion with ab initio calculations. In this cubic structure archetype of new materials with ionic conductivity properties, all 29 optical modes predicted by group theory are Raman-active. All lines have been unambiguously identified on the basis of depolarization ratio measurements. The phonon spectrum is calculated at the center of the Brillouin zone by GGA pseudopotentials within the PWSCF/QE suite. A remarkable agreement is obtained with the experimental frequencies, and a fairly good one is also observed with the Raman scattering cross sections calculated using LDA pseudopotentials for the internal modes of WO42– tetrahedra and the lattice modes as well. All Raman lines are assigned for the first time, and the normal coordinates characteristics are described. The whole results give a large credit to the calculation of the phonon spectra in this structural...

In the title salt, C10H28N44+·4HSO4−, the cation lies about an inversion center. In the crystal, O—H...O and N—H...O hydrogen bonds connect the anions and cations, forming a three-dimensional network.

Polycrystalline samples of β-La2Mo2-ySyO9 (0 ≤ y ≤ 1) are synthesized by solid state reaction of stoichiometric mixtures of La2O3, La2(SO4)3, and MoO3 (alumina crucible, 500 °C, 12 h, firing at 850 °C).

The effect of partial substitution of molybdenum by phosphorus on the global and local structural arrangement of the fast oxide-ion conductor La(2)Mo(2)O(9) (LAMOX) has been studied by X-ray powder diffraction as well as (139)La and (31)P solid state NMR. The diffraction patterns show that La(2)Mo(2-y)P(y)O(9-y/2) forms a solid solution at low phosphorus concentrations, and that there is a structural phase transition upon increasing phosphorus concentration. This phase transition is also reflected in (139)La and (31)P NMR spectra. The possibility to excite (31)P multiple-quantum coherences of one of the (31)P NMR signals gives evidence of an accumulation of phosphorus atoms on neighbouring Mo-type sites already before formation of three-dimensional precipitates. On the basis of our X-ray and NMR results we propose a possible structural arrangement of the compound La(2)Mo(2-y)P(y)O(9-y/2) that explains the experimental observations by crystal twinning.

Powder-solid state reaction route using La 2 (SO 4 ) 3 as sulfur source was used to prepare compositions of the solid solution La 2 Mo 2− y S y O 9 . Single phases were only obtained in the substitution range extending up to y =0.8 (40 mol% S) at the annealing temperature of 850 °C with regard to the limit of stability of the lanthanum sulphate reactant. Within the synthesis conditions, a stabilization of the high temperature β-form is observed from and above y =0.1 (5 mol% S). Temperature-controlled X-ray diffraction and thermogravimetric analyses have shown that La 2 Mo 2− y S y O 9 raw powders undergo thermal decompositions in two steps. Heating above 900 °C, a sulfur depletion to the benefit of molybdenum in La 2 Mo 2− y S y O 9 raw powders leads to the formation of La 2 SO 6 . At higher temperature, the exsolved La 2 SO 6 phase then decomposes into La 2 O 3 , which in turn reacts with the sulfur-depleted La 2 Mo 2 O 9 phase to form La 2 MoO 6 . The present study also reveals that depending on the substitution rate y , the sulfur depletion can be induced by ball-milling of raw powders. Along the La 2 Mo 2− y S y O 9 series, the isovalent substitution of molybdenum by sulfur tends to restrict in magnitude, or even to suppress above 400 °C, the distortive thermal expansion of the cubic β-type structure, thus strongly decreasing the conductance at high temperature.

In this Thesis we consider semi-excited resonances for a h-Pseudo-Differential Operator (h-PDO for short) H(x, hDx; h) on L2(M) induced by a periodic orbit of hyperbolic type at energy E = 0, as arises when M = Rn and H(x, hDx; h) is Schrödinger operator withAC Stark effect, or H(x, hDx; h) is the geodesic flow on an axially symmetric manifold M,extending Poincaré example of Lagrangian systems with 2 degree of freedom. We generalizethe framework of Gérard and Sjöstrand, in the sense that we allow for hyperbolic and ellipticeigenvalues of Poincaré map, and look for (excited) resonances with imaginary part of magnitude hs, with 0 < s < 1,It is known that these resonances are given by the zeroes of a determinant associatedwith Poincaré map. We make here this result more precise, in providing a first order asymptoticsof Bohr-Sommerfeld quantization rule in terms of the (real) longitudinal and (complex)transverse quantum numbers, including the action integral, the sub-principal 1-form and Gelfand-Lidskii index.; On étudie les résonances semi-excitées pour un Opérateur h-Pseudo-différentiel (h-PDO)H(x, hDx) sur L2(M) induites par une orbite périodique de type hyperbolique à l’énergie E = 0. Par exemple M = Rn et H(x, hDx; h) est l’opérateur de Schrödinger avec effet Stark, ouH(x, hDx; h) est le flot géodesique sur une variété axi-symétrique M, généralisant l’exemplede Poincaré de systèmes Lagrangiens à 2 degrés de liberté. On étend le formalisme de Gérard and Sjöstrand, au sens où on autorise des valeurs propres hyperboliques et elliptiques del’application de Poincaré, et où l’on considère des résonances dont la partie imaginaire est del’ordre de hs, pour 0 < s < 1.On établit une règle de quantification de type Bohr-Sommerfeld au premier ordre en fonction des nombres quantiques longitudinaux (réels) et transverses (complexes), incluantl’intégrale d’action le long de l’orbite, la 1-forme sous-principale, et l’indice de Conley-Zehnder.