The Experts below are selected from a list of 69 Experts worldwide ranked by ideXlab platform

O. V. Kotova - One of the best experts on this subject based on the ideXlab platform.

  • GEOMETRIC AND ELECTRONIC STRUCTURE OF AN N,N-ETHYLENE-BIS(SALICYLALDIMINATO) ZINC(II) MOLECULE, ZnO2N2C16H14
    Journal of Structural Chemistry, 2010
    Co-Authors: G. V. Girichev, Nina I. Giricheva, N. V. Tverdova, A. O. Simakov, N. P. Kuz'mina, O. V. Kotova
    Abstract:

    Gas electron diffraction at a temperature T of 641(5) K is used to study the structure of an N,N′-ethylenebis(salicylaldiminato) zinc(II) molecule, ZnO2N2C16H14, further Zn(salen). The structure of a gaseous Zn(salen) complex has C 2 symmetry and is characterized by a substantial turn of two chelating fragments of the ligand with respect to each other, and also by a big difference in the length of coordination bonds: r h1(Zn-O)=1.902(7) A r h1(Zn-N)= 2.027(7) A. Results of the DFT/B3LYP Calculation with 6-31G* and CEP,TZV basis sets of the molecule structure well agree with the experimental data. The electronic structure of Ni(salen), Cu(salen), Zn(salen), and Zn(acacen) molecules is considered.

  • Geometric and electronic structure of an N,N′-ethylene-bis(salicylaldiminato) zinc(II) molecule, ZnO_2N_2C_16H_14
    Journal of Structural Chemistry, 2010
    Co-Authors: G. V. Girichev, Nina I. Giricheva, N. V. Tverdova, A. O. Simakov, N. P. Kuz’mina, O. V. Kotova
    Abstract:

    Gas electron diffraction at a temperature T of 641(5) K is used to study the structure of an N,N′-ethylenebis(salicylaldiminato) zinc(II) molecule, ZnO_2N_2C_16H_14, further Zn(salen). The structure of a gaseous Zn(salen) complex has C _2 symmetry and is characterized by a substantial turn of two chelating fragments of the ligand with respect to each other, and also by a big difference in the length of coordination bonds: r _ h 1(Zn-O)=1.902(7) Å r _ h 1(Zn-N)= 2.027(7) Å. Results of the DFT/B3LYP Calculation with 6-31G* and CEP,TZV basis sets of the molecule structure well agree with the experimental data. The electronic structure of Ni(salen), Cu(salen), Zn(salen), and Zn(acacen) molecules is considered.

A. Ben Rahaiem - One of the best experts on this subject based on the ideXlab platform.

  • FT-IR and Raman spectra and vibrational investigation of bis (4-acetylanilinium) hexachlorostannate using DFT (B3LYP) Calculation
    Physica E: Low-dimensional Systems and Nanostructures, 2016
    Co-Authors: S. Tarchouna, I. Chaabane, A. Ben Rahaiem
    Abstract:

    Abstract 4-acetylanilinium was used as a ligand for the synthesis of the organic/inorganic compound bis (4-acetylanilinium) hexachlorostannate. Vibrational study in the solid state was performed by FT-Raman of the free 4-acetylanilinium ligand C 8 H 9 ON + and by FT-IR and FT-Raman spectroscopies of the [C 8 H 10 NO] 2 SnCl 6 compound. The comparative analysis of the Raman spectra of the title compound with that of the free ligand was discussed. The structure of the [C 8 H 10 NO] 2 SnCl 6 was optimized by density functional theory (DFT) using B3LYP method and shows that the calculated values obtained by B3LYP/LanL2DZ basis are in a better agreement with the experimental data reported by Song et al. (2011) [1] than those obtained by B3LYP/LanL2MB basis. The vibrational frequencies are calculated using density functional theory (DFT) with the B3LYP/LanL2DZ basis, and scaled by various 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.

G. V. Girichev - One of the best experts on this subject based on the ideXlab platform.

  • GEOMETRIC AND ELECTRONIC STRUCTURE OF AN N,N-ETHYLENE-BIS(SALICYLALDIMINATO) ZINC(II) MOLECULE, ZnO2N2C16H14
    Journal of Structural Chemistry, 2010
    Co-Authors: G. V. Girichev, Nina I. Giricheva, N. V. Tverdova, A. O. Simakov, N. P. Kuz'mina, O. V. Kotova
    Abstract:

    Gas electron diffraction at a temperature T of 641(5) K is used to study the structure of an N,N′-ethylenebis(salicylaldiminato) zinc(II) molecule, ZnO2N2C16H14, further Zn(salen). The structure of a gaseous Zn(salen) complex has C 2 symmetry and is characterized by a substantial turn of two chelating fragments of the ligand with respect to each other, and also by a big difference in the length of coordination bonds: r h1(Zn-O)=1.902(7) A r h1(Zn-N)= 2.027(7) A. Results of the DFT/B3LYP Calculation with 6-31G* and CEP,TZV basis sets of the molecule structure well agree with the experimental data. The electronic structure of Ni(salen), Cu(salen), Zn(salen), and Zn(acacen) molecules is considered.

  • Geometric and electronic structure of an N,N′-ethylene-bis(salicylaldiminato) zinc(II) molecule, ZnO_2N_2C_16H_14
    Journal of Structural Chemistry, 2010
    Co-Authors: G. V. Girichev, Nina I. Giricheva, N. V. Tverdova, A. O. Simakov, N. P. Kuz’mina, O. V. Kotova
    Abstract:

    Gas electron diffraction at a temperature T of 641(5) K is used to study the structure of an N,N′-ethylenebis(salicylaldiminato) zinc(II) molecule, ZnO_2N_2C_16H_14, further Zn(salen). The structure of a gaseous Zn(salen) complex has C _2 symmetry and is characterized by a substantial turn of two chelating fragments of the ligand with respect to each other, and also by a big difference in the length of coordination bonds: r _ h 1(Zn-O)=1.902(7) Å r _ h 1(Zn-N)= 2.027(7) Å. Results of the DFT/B3LYP Calculation with 6-31G* and CEP,TZV basis sets of the molecule structure well agree with the experimental data. The electronic structure of Ni(salen), Cu(salen), Zn(salen), and Zn(acacen) molecules is considered.

  • Investigation of the structure and energy of β-diketonates. XIV. Composition of overheated vapors and the molecular structure of monomeric yttrium tris-hexafluoroacetylacetonate Y(C_5O_2HF_6)_3
    Journal of Structural Chemistry, 2007
    Co-Authors: G. V. Girichev, N. V. Tverdova, N. P. Kuz’mina, V. V. Rybkin, S. A. Shlykov, I. G. Zaitseva
    Abstract:

    Simultaneous electron diffraction and mass spectrometry along with a quantum chemical (DFT/B3LYP) Calculation are applied to study the molecular structure of yttrium tris -hexafluoroacetylacetonate Y(hfa)_3. The superheating of the vapor in a double two-temperature effusion cell shows that up to a temperature of ∼200°C ions containing from one to three metal atoms are formed, and the most intensive ion has the stoichiometry of (Y_2L_5)^+ at a temperature below ∼120°C. The monomer starts to noticeably decompose at temperatures above 330°C.The electron diffraction patterns of monomers are obtained at T _exp = 208(5)°C. According to the results of theoretical and experimental investigations, Y(hfa)_3 molecule has D _3-symmetry. The rotation angle of triangular O-O-O faces with respect to their position in the regular prism is equal to 14.4(1)°C. The values of internuclear distances and valence angles ( r _ h 1-geometry) are: r (Y-O) = 2.259(6) Å, r (C-O) = 1.263(6) Å, r (C-C_r) = 1.413(4) Å, r (C-C_F) = 1.531(4) Å, r (C-F) = 1.344(3) Å, O-Y-O = 75.2(2)°, O-C-C_F = 113.8(2)°, C-C_F-F = 112.4(2)°. The results of quantum chemical Calculations are well consistent with the experimental data.

A.b. Carvalho - One of the best experts on this subject based on the ideXlab platform.

  • A theoretical study of nonlinearity in heterocyclic hydrogen-bonded complexes
    Spectrochimica acta. Part A Molecular and biomolecular spectroscopy, 2005
    Co-Authors: Boaz G. Oliveira, Regiane C. M. U. Araújo, Mozart N. Ramos, E.m. Duarte, A.b. Carvalho
    Abstract:

    Abstract Ab initio Calculations are performed at the MP2/6-311++G(d,p) and DFT/B3LYP/6-311++G(d,p) theoretical levels to obtain geometries, H-bond energies and harmonic infrared vibrational properties for the C s symmetry structures of heterocyclic hydrogen-bonded complexes, C n H m Y–HX. The H-bond lengths in DFT/B3LYP Calculation level are in better agreement with the experimental values than the MP2 results. The geometry optimization are interpreted in terms of hydrogen bond nonlinearity represented by θ and ϕ angles, once the hydrogen bond is formed among n -electrons pairs of the heteroatom in heterocyclic and the hydrogen atom in HX. The hydrogen bond energy after of the zero-point vibrational energy (ZPE) and basis set superposition error (BSSE) corrections are overestimated at DFT/B3LYP, whereas the MP2 BSSE corrections are very large than corresponding DFT/B3LYP. For example, the BSSE corrections for the C 2 H 4 S–HNC complex are 7.60 and 0.09 kJ mol −1 in MP2 and DFT/B3LYP Calculations levels, respectively. The new vibrational modes in infrared harmonic spectrum arising from complexation show several interesting features, especially the intermolecular stretching mode.

Semiha Bahçeli - One of the best experts on this subject based on the ideXlab platform.

  • Quantum chemical investigations of a co-crystal of 1,3,5-tris(4-hydroxyphenyl)benzene and 2,4,6-trimethoxy-1,3,5-triazine
    Monatshefte für Chemie - Chemical Monthly, 2015
    Co-Authors: Ömer Dereli, Semiha Bahçeli, Asghar Abbas, Muhammad Moazzam Naseer
    Abstract:

    In the present study, quantum chemical investigations were carried out on our previously reported co-crystal based on 1,3,5-tris(4-hydroxyphenyl)benzene and 2,4,6-trimethoxy-1,3,5-triazine, which showed CH···π and π···π interactions driven layer-by-layer self-assembly of hydrogen-bonded hexagonal blocks in the solid state. Using the DFT/B3LYP Calculation method with 6-311++G(d,p) basis set in the ground state, the optimized molecular geometric parameters, conformational analysis, vibrational wavenumbers and their assignments, the HOMO–LUMO analysis, molecular electrostatic potential, thermodynamic properties, and atomic charges were calculated to understand various structural features that are playing an important role in its packing. Furthermore, the simulated infrared and Raman spectra of the co-crystal are plotted using the calculated results. The calculated results are in a good agreement with experimental data. The study with constructive propositions may be helpful in understanding complex self-assembled systems and in the construction of similar molecular self-assemblies. Graphical abstract

  • FT-IR, Micro-Raman and UV-vis spectroscopic and quantum chemical investigations of free 2,2'-dithiodipyridine and its metal (Co, Cu and Zn) halide complexes
    Spectrochimica acta. Part A Molecular and biomolecular spectroscopy, 2013
    Co-Authors: Halil Gökce, Semiha Bahçeli
    Abstract:

    Abstract In this study the elemental analysis results, molecular geometries, vibrational and electronic absorption spectra of free 2,2′-dithiodipyridine(C 10 H 8 N 2 S 2 ), (or DTDP) (with synonym, 2,2′-dipyridyl disulfide) and M(C 10 H 8 N 2 S 2 )Cl 2 (M = Co, Cu and Zn) complexes have been reported. Vibrational wavenumbers of free DTDP and its metal halide complexes have been calculated by using DFT/B3LYP Calculation method with 6-31++G(d,p) and Lanl2DZ basis sets, respectively, in the ground state, for the first time. The calculated fundamental vibrational frequencies are in a good agreement with experimental data. The HOMO, LUMO and MEP analyses of all compounds are performed by DFT method.