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The X-ray crystallographic analysis of 1,7-difluoro-1,1,3,5,7,7-hexanitro-3,5-diazaheptane has been carried out. We have also determined its sensitivity to mechanical actions and a set of calculated and experimental data on explosion characteristics.

We report here the synthesis of the Z-3N(2-ethoxyphenyl)-2-N¢(2-ethoxyphenyl)-imino-thiazolidin-4-one compound. The crystal structure is determined by X-ray diffraction. The compound crystallizes in the monoclinic system with the space group P 2₁/ n and cell parameters: a = 9.4094(10) Å, b = 9.3066(10) Å, c = 20.960(2) Å, b = 99.0375(10)°, V = 1812.7(3) ų and Z = 4. The structure is refined to final R = 0.05 for 2083 observed reflections. The molecule in the crystal exhibits the intermolecular hydrogen bonds of C-H…O, C-H…N, and C-H…S types. Ab initio calculations are also performed at Hartree-Fock (HF) and density functional theory (DFT) levels. The full HF and DFT geometry optimization is carried out using the 6-31G( d , p ) basis set. The observed molecular structure is compared with that calculated by both HF and DFT methods. The optimized geometry of the titled compound is found to be consistent with the structure determined by X-ray diffraction.

Sterically hindered meso -tetramethyl- meso -tetraarylcalix[4]pyrroles 1-4 where aryl is p -fluorophenyl 1, p- chlorophenyl 2, and p -methylphenyl 3, 4 (configurational isomers) are synthesized and purified by the recrystallization technique. They are characterized by IR, ¹H and ¹³C NMR, and mass spectroscopy. Configurational isomers aabb (3) and aaaa (4) of meso -tetramethyl- meso -tetramethylphenylcalix[4]pyrroles are assigned by the ¹H NMR studies and confirmed by the X-ray diffraction analysis. The single crystal X-ray diffraction analysis reveals that the ethanol adduct of 1, the acetone adduct of 2 and 3 adopt the 1,2-conformation while the acetone-water adduct of 1 and the acetone adduct of 4 adopt partial cone and cone conformations respectively. The conformational diversity is due to non-covalent interactions among the encapsulated guest, pyrrolic NH protons, and meso- substituents. Anion binding studies (F^-, Cl^-, CH₃COO^-, _{) are carried out through ¹H NMR titrations; the binding constants are evaluated using the EQNMR program, displaying that they are more selective towards fluoride rather than other anions with the 1:1 stoichiometry. The configuration of compounds drastically influences the ion-recognition processes.}

A new chalcone derivative 1-phenyl-3-(4-bis(2-chloroethyl)aminophenyl)-2-propen-1-one with the molecular formula C₁₉H₁₉Cl₂NO is synthesized by the Claisen-Schmidt condensation reaction. A transparent yellow single crystal was obtained by the slow evaporation solution growth technique using ethanol at room temperature. The compound crystallizes in the triclinic crystal system, P -1 space group, Z = 4, calculated density = 1.332 mg/m³, V = 1736.00(8) ų with unit cell parameters a = 7.8899(2) Å, b = 14.1924(4) Å, c = 15.7879(4) Å, a = 83.1280(10)°, b = 81.929(2)°, g =86.4820°. The second harmonic generation efficiency is found to be 1.5 times higher than that of urea. Thermal stability of the crystal is found to be 250°C determined from the thermogravimetric analysis. The FT-IR spectroscopy is used to identify the functional groups of the synthesized compound. The optical behavior of the grown crystal is examined by the UV-visible spectral analysis, which shows that the absorbance is almost negligible in the wavelength range 400-1300 nm.

We report the synthesis and characterization of two new macrocyclic Schiff base compounds: a 15-membered (1) and 16-membered (2) one. Their synthesis involves a Schiff base condensation of 2,2-dimethylpropanediamine and two dialdehydes: 5,5¢-dimethoxy-2,2¢-(ethane-1,2-diyldioxy)dibenzaldehyde and 5,5¢-dimethoxy-2,2¢-(propane-1,3-diyldioxy)dibenzaldehyde. The compounds are characterized by elemental analysis (CHN), FT-IR, ¹H and ¹³C-NMR spectroscopy, and single crystal X-ray diffraction. Compound 1 crystallizes in the monoclinic space group Cc with a = 11.0668(5) Å, b = 11.7962(5) Å, c = 17.1980(9) Å, b = 103.611(5)°, V = 2182.08(18) ų, Z = 4, R ( F ² > 2s( F ²)) = 0.048 and wR ( F ²) == 0.150, while compound 2 crystallizes in the monoclinic space group C 2/ c with a = 38.4782(15) Å, b = 5.6309(2) Å, c = 20.4029(7) Å, b = 102.524(4)°, V = 4315.4(3) ų, Z = 8, R ( F ² > 2s( F ²)) = 0.051 and wR ( F ²) = 0.130.

By single crystal X-ray diffraction the features of the molecular and crystal structures of 2-morpholino-5-trifluoromethyl-1,3,4-thiadiazole are determined. This is the main substance of the certified reference material of trifluoromethylmorpholinothiadiazole for the quantitative elemental analysis of fluoroorganic compounds.

By the interaction of methyl 1-bromocyclobutanecarboxylate with zinc and ethyl 6-bromo-2-oxo-2Н-chromene-3-carboxylate, ethyl E-6-bromo-4-[1-(methoxycarbonyl)cyclobutyl]-2-oxochromene-3-carboxylate is obtained whose structure is determined by X-ray crystallography.

A series of fluoro- and hydroxy-substituted thiocarboxyhydrazones, 2-(3-fluorobenzylidene)-N-methylhydrazinecarbothioamide (1), 2-(2,3-difluorobenzylidene)-N-methylhydrazinecarbothioamide (2), and 2-(2-hydroxybenzylidene)-N-methylhydrazinecarbothioamide (3), are synthesized and characterized by elemental analysis, IR and UV-vis spectra, and single crystal X-ray diffraction. Structures of the three compounds are similar, but with a slight modification due to fluoro substituting groups. The crystal structures of the compounds are stabilized by hydrogen bonds and π⋯π interactions. The antimicrobial activity of the compounds shows that they are effective against some bacteria.

Two bromo-substituted Schiff bases 5-bromo-2-methoxy-4-( p -tolyliminomethyl)phenol (1) and 2-bromo-6-[(6-methylpyridin-2-ylimino)methyl]phenol (2) are prepared and characterized by elemental analysis, ¹H and ¹³C NMR, and single crystal X-ray diffraction. Compound 1 crystallizes in the triclinic space group _{with unit cell dimensions a = 6.228(1) Å, b = 10.929(2) Å, c = 21.312(2) Å, α = 104.230(2)°, β = 91.780(2)°, γ = 90.890(2)°, V = 1405.0(4) ų, Z = 4, R 1 = 0.0359, and wR 2 = 0.0830. Compound 2 crystallizes in the monoclinic space group P 21/ c with unit cell dimensions a = 8.180(2) Å, b = 12.011(3) Å, c = 12.843(3) Å, β = 106.263(2)°, V = 1211.4(4) ų, Z = 4, R 1 = 0.0364, and wR 2 = 0.0889. X-ray diffraction indicates that the Schiff base molecules of the compounds display trans configuration with respect to the C=N double bonds. The crystal structures of the compounds are stabilized by hydrogen bonds and weak π⋯π interactions.}

The title compound C₂₉H₂₈N₈O₄, 1,1¢-(propane-1,3-diyl)bis(5-benzyl-7-methyl-1H-pyrazolo[3,4-d]××pyrimidine-4,6(5H,7H)-dione) is characterized by single crystal X-ray diffraction. It crystallizes in the centrosymmetric space group P _{, with two molecules in the unit cell. There is one formula unit in the asymmetric unit with a folded conformation due to arene interaction and an unusually large angle of 124° in the propylene linker. The crystal structure is stabilized due to the presence of π-π and C-H…O interactions.}