scholarly journals Structure of Biologically Active Benzoxazoles: Crystallography and DFT Studies

2021 ◽  
Vol 68 (1) ◽  
pp. 144-150
Author(s):  
Una Glamočlija ◽  
Selma Špirtović-Halilović ◽  
Mirsada Salihović ◽  
Iztok Turel ◽  
Jakob Kljun ◽  
...  
Keyword(s):  
Single Crystal ◽  
Crystal Structures ◽  
Energy Gap ◽  
Molecular Geometry ◽  
Biologically Active ◽  
Basis Set ◽  
Single Crystal Diffraction ◽  
X Ray ◽  
Experimental Values ◽  
Homo Lumo

Using X-ray single crystal diffraction, the crystal structures of biologically active benzoxazole derivatives were determined. DFT calculation was performed with standard 6-31G*(d), 6-31G** and 6-31+G* basis set to analyze the molecular geometry and compare with experimentally obtained X-ray crystal data of compounds. The calculated HOMO-LUMO energy gap in compound 2 (2-(2-hydroxynaphtalen-1-yl)-4-methyl-7-isopropyl-1,3-benzoxazol-5-ol) is 3.80 eV and this small gap value indicates that compound 2 is chemically more reactive compared to compounds 1 (4-methyl-2-phenyl-7-isopropyl-1,3-benzoxazol-5-ol) and 3 (2-(4-chlorophenyl)-4-methyl-7-isopropyl- 1,3-benzoxazol-5-ol). The crystal structures are stabilized by both intra- and intermolecular hydrogen bonds in which an intermolecular O–H⋅⋅⋅N hydrogen bond generates N3 and O7 chain motif in compounds 1, 2, and 3, respectively. The calculated bond lengths and bond angles of all three compounds are remarkably close to the experimental values obtained by X-ray single crystal diffraction.

Preparation and Crystal Structures of Low-Valent Zirconocene Complexes Containing Tetramethyl(phenyl)cyclopentadienyl Ligands

2007 ◽  
Vol 72 (5-6) ◽  
pp. 679-696 ◽  
Author(s):  
Michal Horáček ◽  
Jiří Pinkas ◽  
Jiří Kubišta ◽  
Ivana Císařová ◽  
Róbert Gyepes ◽  
...  
Keyword(s):  
Single Crystal ◽  
Crystal Structures ◽  
Spectroscopic Methods ◽  
Single Crystal Diffraction ◽  
X Ray ◽  
Cyclopentadienyl Ligands ◽  
Low Valent

Zirconocene complex [ZrCl2(η5-C5Me4Ph)2] (1) prepared by metathesis of the appropriate lithium cyclopentadienide and ZrCl4 was reduced with magnesium in tetrahydrofuran in the presence of excess bis(trimethylsilyl)acetylene, yielding the low-valent complex [Zr(η5-C5Me4Ph)2- (η2-Me3SiC≡CSiMe3)] (2). However, in addition to 2, the reduction afforded an unexpected Zr(II) complex [Zr(η5-C5Me4Ph)2(s-trans-η4-buta-1,3-diene)] (3). Compounds 1-3 were characterized by spectroscopic methods and by X-ray single-crystal diffraction.

scholarly journals (E)-1-(Benzo[d][1,3]dioxol-5-yl)-3-([2,2′-bithiophen]-5-yl)prop-2-en-1-one: crystal structure, UV–Vis analysis and theoretical studies of a new π-conjugated chalcone

2019 ◽  
Vol 75 (5) ◽  
pp. 632-637
Author(s):  
Ainizatul Husna Anizaim ◽  
Muhamad Fikri Zaini ◽  
Muhammad Adlan Laruna ◽  
Ibrahim Abdul Razak ◽  
Suhana Arshad
Keyword(s):  
Density Functional ◽  
Energy Gap ◽  
Weak Interactions ◽  
Basis Set ◽  
Molecular Orbital Calculations ◽  
Functional Theory ◽  
Compound C ◽  
Homo And Lumo ◽  
Experimental Values ◽  
Homo Lumo

In the title compound, C18H12O3S2, synthesized by the Claisen–Schmidt condensation method, the essentially planar chalcone unit adopts an s-cis configuration with respect to the carbonyl group within the ethylenic bridge. In the crystal, weak C—H...π interactions connect the molecules into zigzag chains along the b-axis direction. The molecular structure was optimized geometrically using Density Functional Theory (DFT) calculations at the B3LYP/6–311 G++(d,p) basis set level and compared with the experimental values. Molecular orbital calculations providing electron-density plots of HOMO and LUMO molecular orbitals and molecular electrostatic potentials (MEP) were also computed both with the DFT/B3LYP/6–311 G++(d,p) basis set. The experimental energy gap is 3.18 eV, whereas the theoretical HOMO–LUMO energy gap value is 2.73 eV. Hirshfeld surface analysis was used to further investigate the weak interactions present.

scholarly journals Structural, optical, thermal and NLO behavior of zinc hydrogen maleate dihydrate single crystal

2018 ◽  
Vol 35 (4) ◽  
pp. 773-784
Author(s):  
S. Karuna ◽  
A.R. Balu ◽  
S. Muthu ◽  
D. Shyamala ◽  
Z. Delci ◽  
...  
Keyword(s):  
Single Crystal ◽  
Energy Gap ◽  
Basis Set ◽  
Potential Energy Distribution ◽  
Third Order ◽  
Tauc Plot ◽  
Ft Ir ◽  
Homo Lumo ◽  
Order Susceptibility ◽  
Good Agreement

Abstract Single crystal of zinc hydrogen maleate dihydrate (ZHMD) is grown by slow evaporation method at room temperature. The compound crystallizes in triclinic system with noncentrosymmetric space group P1. FT-IR and FT-Raman spectra of ZHMD are recorded. The versatile DFT is employed to understand the band structure of the crystal. Dipole moment of the molecule, ionization energy and electron affinity are established. The potential energy distribution PED of the vibrational modes is calculated using VEDA4. The results of the optimized molecular structure are compared with the single crystal XRD data. The Mulliken and NBO charges are calculated and interpreted. Optical properties of the grown crystal are analyzed using UV-Vis spectrum. Energy gap determined by Tauc plot is in a good agreement with the theoretical value calculated from HOMO-LUMO energies. Thermogravimetric analysis is done to assess the thermal behavior of the ZHMD crystal. Various thermodynamic parameters are calculated using the basis set B3LYP. The first order hyperpolarizability values of ZHMD establish its NLO nature. The molecular electrostatic potential MEP of the molecule is obtained. Third-order nonlinear response is studied using Z-scan technique and the corresponding parameters such as absorption coefficient, refractive index and third-order susceptibility are determined.

scholarly journals FT-IR, FT-Raman, Homo-Lumo and UV-Visible Spectral Analysis of E-(N′-(1H-INDOL-3YL) Methylene Isonicotinohydrazide)

2017 ◽  
Vol 1 (3) ◽  
pp. 1-37
Author(s):  
D. Sumathi ◽  
H. Saleem ◽  
A. Nathiya ◽  
N. RameshBabu ◽  
D. Usha
Keyword(s):  
Energy Gap ◽  
Solid Phase ◽  
Basis Set ◽  
Excitation Energies ◽  
B3lyp Method ◽  
Td Dft ◽  
Ft Ir ◽  
Experimental Values ◽  
Homo Lumo ◽  
Ft Raman

A combined experimental and theoretical study on molecular and vibrational structure of E-N¢ (ICINH) had been carried out. The FTIR, FT-Raman and UV-Vis spectra of ICINH were recorded in the solid phase. The optimized geometry was calculated by B3LYP method with 6-311++G(d,p) level of basis set. The harmonic vibrational frequencies, IR intensities and Raman scattering activities of the title compound were calculated at same level of theory. The scaled theoretical wavenumber showed very good agreement with the experimental values. The mulliken charges and thermodynamic functions of the ICINH were also performed at same level of theory. NLO and a study on the electronic properties such as excitation energies and wavelength, were performed by TD-DFT approach. HOMO–LUMO energy gap was also calculated and interpreted.

Structure Types of Dihydroergotoxine Mesylates

2002 ◽  
Vol 67 (4) ◽  
pp. 490-501 ◽  
Author(s):  
Hana Petříčková ◽  
Jan Čejka ◽  
Michal Hušák ◽  
Bohumil Kratochvíl ◽  
Ivana Císařová ◽  
...  
Keyword(s):  
Single Crystal ◽  
Crystal Structures ◽  
Single Crystal Diffraction ◽  
X Ray ◽  
Ethanol Solvate

Three new crystal structures of dihydroergopeptines: dihydro-α-ergokryptine mesylate monohydrate acetone solvate (1), dihydro-α-ergokryptine mesylate monohydrate nitromethane solvate (2), and dihydroergocornine mesylate monohydrate methanol solvate (3) have been determined by X-ray single crystal diffraction. These structures were compared with published structures of dihydro-α-ergokryptine mesylate monohydrate ethanol solvate (4), dihydro-β-ergokryptine mesylate monohydrate methanol solvate (5), and dihydroergocristine mesylate monohydrate (6).

Structure characterization with neutron powder data of LaGaO3 and NdGaO3 based on X-ray single-crystal data: evidence for an inversion center

1996 ◽  
Vol 211 (12) ◽  
Author(s):  
W. Marti ◽  
P. Fischer ◽  
J. Schefer ◽  
F. Kubel
Keyword(s):  
Single Crystal ◽  
Crystal Structures ◽  
Powder Diffraction ◽  
Neutron Powder Diffraction ◽  
Structure Characterization ◽  
Inversion Center ◽  
Crystal Data ◽  
Single Crystal Diffraction ◽  
X Ray

AbstractFrom neutron powder diffraction intensities it is often problematic to distinguish between centrosymmetry and non-centrosymmetry. X-ray single crystal diffraction may be more accurate. In this paper we compare refinement results of crystal structures on the basis of neutron powder data of orthorhombic NdGaO

Hydrogen bonding in hydroxypyridium salts

2018 ◽  
Vol 233 (7) ◽  
pp. 501-506
Author(s):  
Andrei V. Mironov ◽  
Victor A. Tafeenko ◽  
Dmitrii Yu. Grebenkin ◽  
Alexander E. Oblezov
Keyword(s):  
Hydrogen Bonding ◽  
Oxygen Atom ◽  
Single Crystal ◽  
Crystal Structures ◽  
Diffraction Data ◽  
Nitrate Anion ◽  
Single Crystal Diffraction ◽  
Space Group ◽  
X Ray ◽  
Unit Cells

Abstract The crystal structures of 6-methyl-2-ethyl-3-hydroxypyridiniun nitrate (C8H12NO)NO3 (I) and fumarate (C8H12NO)2C4H2O4 (II) were solved and refined from X-ray single crystal diffraction data (CuKα, (I) a=4.6477(2), b=14.5906(9), c=14.5551(8) Å, β=99.100(4)°, space group P21/c, Z=4, Rp/Rwp=0.033/0.047; (II) a=8.8293(3), b=13.4268(5), c=8.3893(3) Å, β=96.303(3)°, space group P21/c, Z=2, Rp/Rwp= 0.034/0.049). Both structures are built of infinite chains along ac diagonal of the unit cells formed by hydrogen bonding between the hydroxypyridium cation and the corresponding anion. Each fumarate anion is linked to four hydroxypyridium cations while nitrate anion is connected with two hydroxypyridium cations only leaving one oxygen atom in the nitrogen group isolated.

scholarly journals Synthesis, X-ray crystal structure, Hirshfeld surface analysis and DFT studies of (E)-N′-(2-bromobenzylidene)-4-methylbenzohydrazide

2019 ◽  
Vol 75 (2) ◽  
pp. 109-114 ◽  
Author(s):  
Azhagan Ganapathi Anitha ◽  
Chidambaram Arunagiri ◽  
Annamalai Subashini
Keyword(s):  
Surface Analysis ◽  
Density Functional ◽  
Energy Gap ◽  
Hirshfeld Surface ◽  
Basis Set ◽  
Hirshfeld Surface Analysis ◽  
Functional Theory ◽  
X Ray ◽  
Homo Lumo ◽  
Good Support

The title molecule, C15H13BrN2O, displays a trans configuration with respect to the C=N double bond. The dihedral angle between the bromo- and methyl-substituted benzene rings is 16.1 (3)°. In the crystal, molecules are connected by N—H...O and weak C—H...O hydrogen bonds, forming R 2 1(6) ring motifs and generating chains along the a–axis direction. The optimized structure generated theoretically via density functional theory (DFT) using standard B3LYP functional and 6–311 G(d,p) basis-set calculations renders good support to the experimental data. The HOMO–LUMO behaviour was elucidated to determine the energy gap. The intermolecular interactions were quantified and analysed using Hirshfeld surface analysis.

On the molecular geometry of 1,2-Di(9-anthryl)ethanes. Crystal structures of two crystalline modifications of 1,2-Bis(10-acetoxy-9-anthryl)ethane

1982 ◽  
Vol 35 (11) ◽  
pp. 2357 ◽  
Author(s):  
H Becker ◽  
SR Hall ◽  
BW Skelton ◽  
AH White
Keyword(s):  
Single Crystal ◽  
Crystal Structures ◽  
Molecular Conformation ◽  
Molecular Geometry ◽  
X Ray Diffraction ◽  
Crystalline Phases ◽  
Molecular Conformations ◽  
X Ray ◽  
Β Phase ◽  
Α Phase

In order to define molecular conformations, the crystal structures of two crystalline phases of 1,2- bis(10-acetoxy-9-anthryl)ethane have been determined by single-crystal X-ray diffraction methods at 295 K. Both phases are monoclinic, P21/c. For the 'α'-phase, a 7.609(2), b 14.469(3), c 11.358(3) � β, 96.39(2)�, Z 2. The final residual was 0.034 for 1341 'observed' reflections; the molecule is centrosymmetric about a crystallographic inversion centre. For the 'β'-phase, a 31.264(15), b 5.248(3), c 15.718(6) �,β 97.84(3)�, Z 4, the final residual was 0.052 for 972 'observed' reflections. In this structure two independent, centrosymmetric molecules are found. In both α- and β-form, the molecular conformation is thus 'stretched' rather than 'eclipsed'. The packing patterns of the two modifications have been correlated with their crystal luminescence properties.

scholarly journals Environmentally Friendly Nafion-Catalyzed Synthesis of Substituted 2-Ethyl-3-Methylquinolines from Aniline and Propionaldehyde under Microwave Irradiation

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 877
Author(s):  
Chieh-Kai Chan ◽  
Chien-Yu Lai ◽  
Cheng-Chung Wang
Keyword(s):  
Reaction Mechanism ◽  
Microwave Irradiation ◽  
Single Crystal ◽  
Diffraction Analysis ◽  
Environmentally Friendly ◽  
Single Crystal Diffraction ◽  
X Ray ◽  
Related Data ◽  
Heating Source ◽  
Chemical Structures

Herein, we report a facile synthetic methodology for the preparation of 2,3-dialkylquinolines from anilines and propionaldehydes. This cyclization involved environmentally friendly Nafion® NR50 as an acidic catalyst with microwave irradiation as the heating source. A series of substituted 2-ethyl-3-methylquinolines were prepared from various anilines and propionaldehyde derivatives through this protocol with good to excellent yields. Some new chemical structures were confirmed by X-ray single-crystal diffraction analysis and the related data were provided. The plausible reaction mechanism studies are also discussed.

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