scholarly journals Hemisynthesis, crystal structure and inhibitory effect of sesquiterpenic thiosemicarbazones and thiazolidin-4-ones on the corrosion behaviour of stainless steel in 1 M H2SO4 solution

2019 ◽  
Vol 75 (6) ◽  
pp. 623-632 ◽  
Author(s):  
Abdoullah Bimoussa ◽  
Yassine Koumya ◽  
Abdesselam Abouelfida ◽  
Moulay Youssef Ait Itto ◽  
Abdelaziz Benyaich ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Corrosion Behaviour ◽  
Steel Corrosion ◽  
Inhibitory Effect ◽  
Maximum Efficiency ◽  
Boat Conformation ◽  
X Ray Diffraction ◽  
Energy Band Gap ◽  
X Ray ◽  
Dispersion Effects

Treatment of thiosemicarbazones prepared from sesquiterpenes with ethyl 2-bromoacetate in the presence of sodium acetate afforded the corresponding thiazolidin-4-ones. The structures of all the newly synthesized compounds were established by considering spectral and single-crystal X-ray diffraction data. The title compound, ethyl 2-((Z)-2-{(Z)-[(1aR,5aR,9aS)-1,1-dichloro-1a,5,5,7-tetramethyl-1a,2,3,4,5,5a,8,9-octahydro-1H-benzo[a]cyclopropa[b][7]annulen-8-ylidene]hydrazono}-4-oxothiazolidin-3-yl)acetate, C23H31Cl2N3O3S, 5, crystallizes in the orthorhombic noncentrosymmetric space group P212121 with Z = 4. Within the molecule in the crystal structure, the cyclohexene ring has an envelope conformation and the cycloheptane ring, to which it is fused, has a boat conformation. In the crystal, molecules are linked by C—H...Cl hydrogen bonds forming chains propagating along the b-axis direction. The absolute configuration of the molecule in the crystal could be fully confirmed from anomalous dispersion effects [Flack parameter = −0.04 (2)]. Thiosemicarbazones 1 and 2 are efficient inhibitors for steel corrosion in 1 M H2SO4 solution, with a maximum efficiency of 92.28% at 10−3 M. Furthermore, thiosemicarbazone compounds were found to be more efficient than thiazolidin-4-one derivatives. In addition, cyclic voltammetry was used to characterize the tested molecules, as well to estimate the experimental value of the energy band gap.

Crystal structure determination of the conformation of two bicyclo[3.3.1]nonan-ones

1985 ◽  
Vol 63 (6) ◽  
pp. 1166-1169 ◽  
Author(s):  
John F. Richardson ◽  
Ted S. Sorensen
Keyword(s):  
Crystal Structure ◽  
Direct Methods ◽  
Chair Conformation ◽  
Molecular Structures ◽  
Boat Conformation ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Final Agreement

The molecular structures of exo-7-methylbicyclo[3.3.1]nonan-3-one, 3, and the endo-7-methyl isomer, 4, have been determined using X-ray-diffraction techniques. Compound 3 crystallizes in the space group [Formula: see text] with a = 15.115(1), c = 7.677(2) Å, and Z = 8 while 4 crystallizes in the space group P21 with a = 6.446(1), b = 7.831(1), c = 8.414(2) Å, β = 94.42(2)°, and Z = 2. The structures were solved by direct methods and refined to final agreement factors of R = 0.041 and R = 0.034 for 3 and 4 respectively. Compound 3 exists in a chair–chair conformation and there is no significant flattening of the chair rings. However, in 4, the non-ketone ring is forced into a boat conformation. These results are significant in interpreting what conformations may be present in the related sp2-hybridized carbocations.

Purification, characterization, crystal structure and NO production inhibitory activity of three new sesquiterpenoids from homalomena occulta

2018 ◽  
Vol 74 (11) ◽  
pp. 1440-1446
Author(s):  
Qi Zhang ◽  
Li Ma ◽  
Zhaoxia Qu ◽  
Guige Hou ◽  
Yanan Wang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
2D Nmr ◽  
Inhibitory Effect ◽  
Raw 264.7 Cells ◽  
No Production ◽  
Raw 264.7 ◽  
X Ray Diffraction ◽  
X Ray ◽  
Spectroscopic Analyses

Two new isodaucane-type sesquiterpenoids, namely (1R,4S,5S,6R,7S,10R)-isodauc-6,7,10-triol, C15H28O3, (1), and (1R,4S,5S,6S,7S,10R)-isodauc-6,7,10-triol, (2), and a new eudesmane-type sesquiterpenoid, 1β,4β,5α-trihydroxyeudesmane, (3), were obtained from the rhizomes of homalomena occulta with the aid of column chromatography. Their structures were elucidated based on extensive spectroscopic analyses, including 1D NMR, 2D NMR and HRESIMS. The structure of (1) was confirmed by single-crystal X-ray diffraction and the absolute configuration was assigned with respect to that of the precursor. The single-crystal structure reveals that adjacent molecules of (1) embrace through two groups of intermolecular O—H...O hydrogen bonds to generate a two-dimensional sheet with a 63-net topology. The three compounds were evaluated for their activity against lipopolysaccharide-induced production of nitrogen oxide (NO) in RAW 264.7 cells, and (1) showed an inhibitory effect on NO production, with IC50 values of 5.7±0.22 µM.

The X-Ray Crystal Structure of 1,2-3,4-Di-O-isopropylidene-4-C-methylthiomethoxy-β-L-arabino-hexoseptanos-5-ulose

1990 ◽  
Vol 43 (12) ◽  
pp. 2083 ◽  
Author(s):  
DC Craig ◽  
VJ James ◽  
JD Stevens
Keyword(s):  
Crystal Structure ◽  
Title Compound ◽  
Membered Ring ◽  
Boat Conformation ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray

The crystal structure of the title compound (1) has been determined by X-ray diffraction. Crystals of (1) are orthorhombic, space group P21212 with a 11.425(1), b 24.916(1), c 5.8952(3)Ǻ, Z 4. Refinement on 1675 observed reflections measured with Cu Kα radiation converged at R 0.034. The seven- membered ring adopts a boat conformation in which the pseudo plane of symmetry passes through the ring oxygen.

The conformation of (1S,3S,4R)- 1,3,8-Tribromo-p-menthan-2-one

1983 ◽  
Vol 36 (5) ◽  
pp. 1043 ◽  
Author(s):  
RM Carman ◽  
E Horn ◽  
CHL Kennard ◽  
G Smith ◽  
MR Snow ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Diffraction Data ◽  
Boat Conformation ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
A Cell ◽  
Twist Boat

The crystal structure of (1S,3S,4R)-1,3,8-tribromo-p-menthan-2-one has been determined from X-ray diffraction data and refined to a final residual of 0.075 for 635 'observed' reflections. Crystals are orthorhombic, of space group P212121 with four molecules in a cell of dimensions a 15.248(3), b 12.189(3), c 7.201(2) �. The analysis confirms that the molecule exists in a distorted twist-boat conformation.

Corrosion Processes of Uranus B6 and Monel 400 Special Alloys in Deep Eutectic Solvents

2019 ◽  
Vol 70 (8) ◽  
pp. 2968-2972
Author(s):  
Elena Ionela Neacsu ◽  
Virgil Constantin ◽  
Cristina Donath ◽  
Kazimir Yanushkevich ◽  
Aliona Zhivulka ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Corrosion Behaviour ◽  
Choline Chloride ◽  
Deep Eutectic Solvents ◽  
Corrosion Process ◽  
Specific Magnetization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Before And After ◽  
Monel 400

The corrosion behaviour of special alloys (Uranus B6 steel and Monel 400) exposed to chlorine chloride-deep eutectic solvents (DES) at 353 K has been investigated by polarization curves method. The corresponding corrosion parameters in choline chloride-oxalic acid and choline chloride-malonic acid were calculated. Micrographic images before and after immersion in the corrosive medium were obtained. Measurements of the influence of the corrosion process on the crystal structure and specific magnetization of the studied steels was carried out by using X-ray diffraction and respectivelly ponderomotive methods.

Crystal Structure of Dibromo(η4-1,5-cyclooctadiene)palladium(II)

1996 ◽  
Vol 61 (9) ◽  
pp. 1335-1341 ◽  
Author(s):  
Petr Štěpnička ◽  
Ivana Císařová
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Single Crystal ◽  
Boat Conformation ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray ◽  
Square Planar ◽  
Twisted Boat

The crystal structure of [(η4-C8H12)PdBr2] has been determined by a single crystal X-ray diffraction with R = 3.82% for 2 147 independent diffractions. The compound crystallizes with the symmetry of orthorhombic space group P212121 (No. 19) within the following parameters: a = 7.0785(5) Å, b = 11.1896(9) Å, c = 12.514(1) Å, V = 991.2(1) Å3, Z = 4. The square planar arrangement of ligands around Pd(II) is distorted due to the steric requirements of 1,5-cyclooctadiene in a twisted boat conformation. Formula units are joined by the weak C2-H2...Br1(1 + x, y, z) hydrogen bonds.

Crystal Structure, Antimicrobial Activity and Oxidation Resistance of N,N′-Bis(4-hydroxybenzyidene)azine

2013 ◽  
Vol 634-638 ◽  
pp. 918-921
Author(s):  
Dong Qing Li ◽  
Xu Jian Luo ◽  
Mian Jia Tan
Keyword(s):  
Crystal Structure ◽  
Antimicrobial Activity ◽  
Schiff Base ◽  
Oxidation Resistance ◽  
Rice Blast ◽  
Raw Materials ◽  
Inhibitory Effect ◽  
Damping Off ◽  
X Ray Diffraction ◽  
X Ray

In the paper, N,N′-bis(4-hydroxybenzyidene)azine (BHBYA) has been synthesized by p-hydroxybenzaldehyde and hydrazine as raw materials. The structure was determined by X-ray diffraction. The Schiff base crystallizes is in the monoclinic P21/c space group. The results of antimicrobial activity showed that it has a good inhibition on Cucumber Damping-Off and Rice Blast. The findings of oxidation resistance experiment indicated that it has an excellent inhibitory effect on peroxidation of olein.

Crystal structure of an inclusion complex between chiral monoaza-15-crown-5 and S(–)-1-phenyl-ethyl ammonium percholorate

2003 ◽  
Vol 218 (5) ◽  
Author(s):  
Süheyla Özbey ◽  
F. B. Kaynak ◽  
M. Toğrul ◽  
N. Demirel ◽  
H. Hoşgören
Keyword(s):  
Crystal Structure ◽  
Inclusion Complex ◽  
Single Crystal ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
New Type

AbstractA new type of inclusion complex, S(–)-1 phenyl ethyl ammonium percholorate complex of R-(–)-2-ethyl - N - benzyl - 4, 7, 10, 13 - tetraoxa -1- azacyclopentadecane, has been prepared and studied by NMR, IR and single crystal X-ray diffraction techniques. The compound crystallizes in space group

Crystal Forms of Semisynthetic Ergot Alkaloid Terguride

2002 ◽  
Vol 67 (4) ◽  
pp. 479-489 ◽  
Author(s):  
Michal Hušák ◽  
Bohumil Kratochvíl ◽  
Ivana Císařová ◽  
Ladislav Cvak ◽  
Alexandr Jegorov ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Ergot Alkaloid ◽  
Simplified Model ◽  
Quantum Mechanical ◽  
Quantum Mechanical Calculations ◽  
X Ray Diffraction ◽  
Torsion Angles ◽  
Crystal Forms ◽  
X Ray ◽  
Independent Molecules

Two new structures of semisynthetic ergot alkaloid terguride created by unusual number of symmetry-independent molecules were determined by X-ray diffraction methods at 150 K. Form A (monoclinic, P212121, Z = 12) contains three symmetry-independent terguride molecules and two molecules of water in the asymmetric part of the unit cell. The form CA (monoclinic, P21, Z = 8) is an anhydrate remarkable by the presence of four symmetry-independent molecules in the crystal structure. Conformations of twelve symmetry-independent molecules that were found in four already described terguride structures are compared with torsion angles obtained by ab initio quantum-mechanical calculations for the simplified model of N-cyclohexyl-N'-diethylurea.

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