K. Guidara

A theoretical study on the molecular structure and vibrational (FT-IR and Raman) spectra of new organic–inorganic compound [N(C3H7)4]2SnCl6

Tetrapropylammoniumchloride was used as a ligand for the synthesis of the new organic-inorganic compound bis-tetrapropylammoniumhexachlorostannate. Vibrational study in the solid state was performed by FT-IR of the free Tetrapropylammoniumchloride ligand (TPACL) and by FT-IR and FT-Raman spectroscopies of the [N(C3H7)4]2SnCl6 compound. The comparative analysis of the Infrared spectra of the title compound with that of the free ligand was discussed. The structure of the [N(C3H7)4]2SnCl6 compound was optimized by density functional theory (DFT) using B3LYP method and shows that the calculated values obtained by B3LYP/LanL2MB basis are in much better agreement with the experimental data than those obtained by B3LYP/LanL2DZ. The vibrational frequencies were evaluated using density functional theory (DFT) with the standard B3LYP/LanL2MB basis, and were scaled using various scale factors. Root mean square (RMS) value was calculated and the small difference between experimental and calculated modes has been interpreted by intermolecular interactions in the crystal.

Alternative current conduction mechanisms of organic-inorganic compound [N(CH3)3H]2ZnCl4

The [N(CH3)3H]2CuCl4 single crystal has been analyzed by X-ray powder diffraction patterns, differential scanning calorimetry (DSC), and electrical impedance spectroscopy. [N(CH3)3H]2CuCl4 crystallizes at room temperature in the monoclinic system with P21/C space group. Three phase transitions at T1 = 226 K, T2 = 264 K, and T3 = 297 K have been evidenced by DSC measurements. The electrical technique was measured in the 10−1–107 Hz frequency range and 203–313 K temperature intervals. The frequency dependence of alternative current (AC) conductivity is interpreted in terms of Jonschers law (developed). The AC electrical conduction in [N(CH3)3H]2CuCl4 compound is studied by two processes which can be attributed to a hopping transport mechanism: the correlated barrier hopping model in phases I, II, and III, the non-overlapping small polaron tunneling model in phase IV. The conduction mechanism is interpreted with the help of Elliots theory, and the Elliots parameters are found.

A.c. conductivity and dielectric study of LiNiPO4 synthesized by solid-state method

LiNiPO4 compound was prepared by the conventional solid-state reaction. The sample was characterized by X-ray powder diffraction, infrared, Raman analysis spectroscopy and electrical impedance spectroscopy. The compound crystallizes in the orthorhombic system, space group Pnma with a = 10·0252(7) Å, b = 5·8569(5) Å and c = 4·6758(4) Å. Vibrational analysis was used to identify the presence of

Synthesis, Infra-red, Raman, NMR and structural characterization by X-ray Diffraction of [C12

\mathrm{PO}_4^{3- }

Synthesis, Infra-red, Raman, NMR and structural characterization by X-ray Diffraction of [C12H17N2]2CdCl4 and [C6H10N2]2Cd3Cl10 compounds

– group in this compound. The complex impedance has been measured in the temperature and frequency ranges 654–716 K and 242 Hz–5 MHz, respectively. The Z′ and Z″ vs frequency plots are well-fitted to an equivalent circuit consisting of series of combination of grains and grain boundary elements. Dielectric data were analysed using complex electrical modulus M* for the sample at various temperatures. The modulus plots are characterized by the presence of two peaks thermally activated. The frequency dependence of the conductivity is interpreted in terms of equation:

Theoretical studies of vibrational spectra of [N(CH3)4]2ZnCl4−yBry compounds with y = 0, 2 and 4

{\sigma_{\mathrm{a}.\mathrm{c}.}}\left( \omega \right)=\left[ {{{{{\sigma_{\mathrm{g}}}}} \left/ {{\left( {1+{\tau^2}{\omega^2}} \right)}} \right.}+\left( {{{{{\sigma_{\infty }}{\tau^2}{\omega^2}}} \left/ {{1+{\tau^2}{\omega^2}}} \right.}} \right)+A{\omega^{\mathrm{n}}}} \right]

Polarized Raman study of [N(C3H7)4]2Cd2Cl6 single crystal

. The near values of activation energies obtained from the analysis of M″, conductivity data and equivalent circuit confirms that the transport is through ion hopping mechanism dominated by the motion of Li+ in the structure of the investigated material.

[N(CH3)3H]2ZnCl4: Ferroelectric properties and characterization of phase transitions by Raman spectroscopy

The synthesis, infra-red, Raman and NMR spectra and crystal structure of 2, 4, 4-trimethyl-4, 5-dihydro-3H-benzo [b] [1, 4] diazepin-1-ium tetrachlorocadmate, [C12H17N2]2CdCl4 and benzene-1,2-diaminium decachlorotricadmate(II) [C6H10N2]2Cd3Cl10 are reported. The [C12H17N2]2CdCl4 compound crystallizes in the triclinic system (P1¯MathType@MTEF@5@5@+=feaafiart1ev1aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacH8bkY=wiFfYlOipiY=Hhbbf9v8qqaqFr0xc9vqpe0di9q8qqpG0dHiVcFbIOFHK8Feei0lXdar=Jb9qqFfeaYRXxe9vr0=vr0=LqpWqaaeaabiGaciaacaqabeaabeqacmaaaOqaaGqaaiab=bfaqnaanaaabaGaeGymaedaaaaa@2D26@ space group) with Z = 2 and the following unit cell dimensions: a = 9.6653(8) Å, b = 9.9081(9) Å, c = 15.3737(2) Å, α = 79.486(1)°, β = 88.610(8)° and γ = 77.550(7)°. The structure was solved by using 4439 independent reflections down to R value of 0.029. In crystal structure, the tetrachlorocadmiate anion is connected to two organic cations through N-H...Cl hydrogen bonds and van der Waals interaction as to build cation-anion-cation cohesion. The [C6H10N2]2Cd3Cl10 crystallizes in the triclinic system (P1¯MathType@MTEF@5@5@+=feaafiart1ev1aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacH8bkY=wiFfYlOipiY=Hhbbf9v8qqaqFr0xc9vqpe0di9q8qqpG0dHiVcFbIOFHK8Feei0lXdar=Jb9qqFfeaYRXxe9vr0=vr0=LqpWqaaeaabiGaciaacaqabeaabeqacmaaaOqaaGqaaiab=bfaqnaanaaabaGaeGymaedaaaaa@2D26@ space group). The unit cell dimensions are a = 6.826 (5)Å, b = 9.861 (7)Å, c = 10.344 (3)Å, α = 103.50 (1)°, β = 96.34 (4)° and γ = 109.45 (3)°, Z = 2. The final R value is 0.053 (Rw = 0.128). Its crystal structure consists of organic cations and polymeric chains of [Cd3 Cl10]4- anions running along the [011] direction, in the [C6H10N2]2Cd3Cl10 compounds hydrogen bond interactions between the inorganic chains and the organic cations, contribute to the crystal packing.PACS Codes: 61.10.Nz, 61.18.Fs, 78.30.-j

Phase transition, conduction mechanism and modulus study of KMgPO4 compound

The synthesis, infra-red, Raman and NMR spectra and crystal structure of 2, 4, 4-trimethyl-4, 5-dihydro-3H-benzo [b] [1, 4] diazepin-1-ium tetrachlorocadmate, [C12H17N2]2CdCl4 and benzene-1,2-diaminium decachlorotricadmate(II) [C6H10N2]2Cd3Cl10 are reported. The [C12H17N2]2CdCl4 compound crystallizes in the triclinic system (P1¯MathType@MTEF@5@5@+=feaafiart1ev1aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacH8bkY=wiFfYlOipiY=Hhbbf9v8qqaqFr0xc9vqpe0di9q8qqpG0dHiVcFbIOFHK8Feei0lXdar=Jb9qqFfeaYRXxe9vr0=vr0=LqpWqaaeaabiGaciaacaqabeaabeqacmaaaOqaaGqaaiab=bfaqnaanaaabaGaeGymaedaaaaa@2D26@ space group) with Z = 2 and the following unit cell dimensions: a = 9.6653(8) Å, b = 9.9081(9) Å, c = 15.3737(2) Å, α = 79.486(1)°, β = 88.610(8)° and γ = 77.550(7)°. The structure was solved by using 4439 independent reflections down to R value of 0.029. In crystal structure, the tetrachlorocadmiate anion is connected to two organic cations through N-H...Cl hydrogen bonds and van der Waals interaction as to build cation-anion-cation cohesion. The [C6H10N2]2Cd3Cl10 crystallizes in the triclinic system (P1¯MathType@MTEF@5@5@+=feaafiart1ev1aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacH8bkY=wiFfYlOipiY=Hhbbf9v8qqaqFr0xc9vqpe0di9q8qqpG0dHiVcFbIOFHK8Feei0lXdar=Jb9qqFfeaYRXxe9vr0=vr0=LqpWqaaeaabiGaciaacaqabeaabeqacmaaaOqaaGqaaiab=bfaqnaanaaabaGaeGymaedaaaaa@2D26@ space group). The unit cell dimensions are a = 6.826 (5)Å, b = 9.861 (7)Å, c = 10.344 (3)Å, α = 103.50 (1)°, β = 96.34 (4)° and γ = 109.45 (3)°, Z = 2. The final R value is 0.053 (Rw = 0.128). Its crystal structure consists of organic cations and polymeric chains of [Cd3 Cl10]4- anions running along the [011] direction, in the [C6H10N2]2Cd3Cl10 compounds hydrogen bond interactions between the inorganic chains and the organic cations, contribute to the crystal packing.PACS Codes: 61.10.Nz, 61.18.Fs, 78.30.-j

Conduction mechanism model, impedance spectroscopic investigation and modulus behavior of the organic–inorganic [(C3H7)4N][SnCl5(H2O)]·2H2O compound

The infrared and Raman spectra of [N(CH3)4]2ZnCl4−yBry, where y = 0, 2 and 4, have been analyzed with ab initio calculations of the vibrational characteristics of constitutive polyhedra, tetramethylammonium [N(CH3)4]+ and [ZnCl4−xBrx]2− (x = 0, 1, 2, 3 and 4) tetrahedra. The optimized geometries, calculated vibrational frequencies, infrared intensities and Raman activities are calculated using Hartree–Fock and density functional theory B3LYP methods with 3-21G, 6-31G(d) and 6-311G+(d,p) basis sets. Calculation of the root mean square difference δrms between the observed and calculated frequencies allows to give scaling factors and to deduce that the best agreements are obtained by B3LYP/6-311G+(d,p) for [N(CH3)4]+ and B3LYP/3-21G for [ZnCl4−xBrx]2−. The present study establishes a strongly reliable assignment of the vibrational modes of [ZnCl4−xBrx]2− tetrahedra based on comparison between experimental and ab initio calculations, both of the frequencies and the intensities of the Raman signals.