Oxygenation of 1-t-Butylcyclohexa-1,3-diene and Cholesta-2,4-diene in the Presence of Trityl Tetrafluoroborate

1988 ◽  
Vol 41 (4) ◽  
pp. 505 ◽  
Author(s):  
MF Arain ◽  
RK Haynes ◽  
SC Vonwiller ◽  
TW Hambley
Keyword(s):  
High Field ◽  
Cation Radical ◽  
Chemical Degradation ◽  
Crystal Data ◽  
X Ray ◽  
Cation Radicals ◽  
Crystallographic Study ◽  
The One ◽  
Allylic Radical ◽  
Tungsten Lamp

Whereas the oxygenation of 1-t-butylcyclohexa-1,3-diene (4) in the presence of catalytic amounts of trityl tetrafluoroborate in dichloromethane at -78° under irradiation from a tungsten lamp gives two dimeric epidioxides as major products, cholesta-2,4-diene (5) gives under the same conditions a monomeric endoperoxide. The structures of the dimeric epidioxides have been established by a combination of chemical degradation, high-field 1H n.m.r. and an X-ray crystallographic study on the diketone (12) derived from one of the epidioxides. A mechanism involving the generation of intermediate monomer and dimer cation radicals is used to account for the formation of the dimeric epidioxides. The dimer cation radicals are expected to be more reactive than the monomer cation radicals towards oxygen. The dimerization is assumed to take place when the diene (4) and its monomer cation radical are aligned so that one reactant lies above the other whereby π-orbital overlap between the rings is maximized; oxygen is constrained to attack the one exposed face of the allylic radical system in the dimer cation radical. This accounts for the unique stereochemistry of the epidioxide products. Crystal data for diketone (12): a 29.975(4), b 5.767(1), c 11.758(2)Ǻ, β 111.67(2)°; C2/c; Z4.

Vicinal-diaryl interactions in stilbenoid hydrocarbons as observed in the through-space charge delocalization of their cation radicals

1999 ◽  
Vol 77 (5-6) ◽  
pp. 913-921 ◽  
Author(s):  
Rajendra Rathore ◽  
Jay K Kochi
Keyword(s):  
Space Charge ◽  
Cation Radical ◽  
Conformational Preference ◽  
Charge Delocalization ◽  
X Ray ◽  
X Ray Crystallography ◽  
Cation Radicals ◽  
Near Ir ◽  
Aromatic Interactions ◽  
Vis Spectroscopy

The conformational preference of vicinal or 1,2-phenyl groups is probed in two classes of ring-substituted 1,2-diphenylbicyclooctene (stilbenoid) hydrocarbons 1a-1d and 2a-2c. UV-vis spectroscopy reveals, and X-ray crystallography verifies, the intramolecular (edge-to-face) orientation for the phenyl-phenyl interaction in stilbenoids 1a-1d. Most importantly, when two pairs of ortho-methyl substituents are present, the cofacial phenyl groups in the stilbenoid donors are established by X-ray crystallography and spectrally observed in the cation radicals (2a+.-2c+.) by the appearance of new bands with strong absorptions in the near IR with λmax = 1100-1315 nm, analogous to those previously observed in intermolecular (aromatic) interactions of aromatic cation radicals.Key words: stilbenoid hydrocarbon, cation radical, aryl-aryl interaction.

The Effect of Different Concentration of Nitrogen in N, S Codoped TiO2

2011 ◽  
Vol 183-185 ◽  
pp. 1791-1794 ◽  
Author(s):  
Yong Bo Lin ◽  
Si Yao Guo ◽  
Feng Fei Wang ◽  
Cheng Hui Zeng ◽  
Na Jiang ◽  
...  
Keyword(s):  
Particle Size ◽  
Calcination Temperature ◽  
Photoelectron Spectroscopy ◽  
Organophosphorus Pesticide ◽  
X Ray Diffraction ◽  
X Ray ◽  
The One ◽  
Anneal Temperature ◽  
Tungsten Lamp

In this paper, the degradation of organophosphorus pesticide by nitrogen and sulfur codoped TiO2 photocatalysts under iodine-tungsten lamp irradiation has been investigated. And we adjusted the concentration of nitrogen to see the change of particle size of nitrogen and sulfur codoping TiO2. According to the X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), the different concentration of N, S codoping under different calcination temperature was discussed. N, S codoped TiO2 sample has a smaller particle size at a low anneal temperature than the one at high anneal temperature.

scholarly journals Isolation of a chiral anthracene cation radical: X-ray crystallography and computational interrogation of its racemization

2017 ◽  
Vol 53 (18) ◽  
pp. 2748-2751 ◽  
Author(s):  
Maxim V. Ivanov ◽  
Khushabu Thakur ◽  
Anshul Bhatnagar ◽  
Rajendra Rathore
Keyword(s):  
Charge Transfer ◽  
Dft Calculations ◽  
Cation Radical ◽  
Enantioselective Synthesis ◽  
X Ray ◽  
X Ray Crystallography ◽  
Anthracene Derivative ◽  
Cation Radicals ◽  
Radical Salt ◽  
Charge Transfer Materials

Chiral cation-radicals hold significant promise as charge-transfer materials, chiroptical switches, and catalysts for enantioselective synthesis. Herein we identify a chiral anthracene derivative that forms a robust cation-radical salt as established by X-ray crystallography and DFT calculations.

Molecular structure and spectroscopic properties of octaethylbenzochloracene, the porphycene analog of a benzochlorin

2005 ◽  
Vol 09 (12) ◽  
pp. 864-871 ◽  
Author(s):  
Kathleen M. Barkigia ◽  
Byron C. Robinson ◽  
Mark W. Renner
Keyword(s):  
Molecular Structure ◽  
Absorption Band ◽  
Benzene Ring ◽  
Optical Spectrum ◽  
Pyrrole Ring ◽  
Cation Radical ◽  
Blue Shift ◽  
Spectroscopic Properties ◽  
X Ray ◽  
The One

The X-ray structure, electrochemistry, and optical spectroscopy of the porphycene analog of a benzochlorin, octaethylbenzochloracene (OEBzC) are reported. The OEBzC macrocycle is easier to oxidize and harder to reduce than octaethylporphycene (OEPc). The optical spectra of OEBzC and of the diacid salt are also reported. The optical spectrum for the one-electron oxidation of OEBzC is indicative of π-cation radical formation. In porphyrins, saturation of one pyrrole ring and addition of an exocyclic benzene ring progressively red-shifts the first absorption band. For porphycenes, saturation of one pyrrole ring results in a 35 nm blue shift in the first absorption relative to OEPc. Compared to 2,3-dihydroporphycene (DHPc), the first absorption band in OEBzC is red-shifted 24 nm. These studies further illustrate how the fused exocyclic benzene ring influences the macrocycle conformation, chemical and physical properties of porphycenes.

Crystal data and X-ray powder diffraction data of two derivatives of 4-chloro-2,2′-iminodibenzoic acid: diethyl 4-chloro-2,2′-iminodibenzoate, C18H18ClNO4, and dimethyl 4-chloro-2,2′-iminodibenzoate, C16H14ClNO4

1998 ◽  
Vol 13 (3) ◽  
pp. 175-177
Author(s):  
Héctor Novoa de Armas ◽  
Armando Paneque Quevedo ◽  
José Antonio Henao Martínez
Keyword(s):  
Powder Diffraction ◽  
Crystal Data ◽  
Space Group ◽  
X Ray ◽  
Cell Dimensions ◽  
The One ◽  
Unit Cell Dimensions ◽  
Derivatives Of ◽  
Monoclinic Cell ◽  
Good Agreement

Two derivatives of 4-chloro-2,2′-iminodibenzoic acid: diethyl 4-chloro-2,2′-iminodibenzoate, C18H18ClNO4, and dimethyl 4-chloro-2,2′-iminodibenzoate C16H14ClNO4, have been investigated by means of X-ray powder diffraction. The unit cell dimensions were determined from diffractometer methods, using monochromatic CuKα1 radiation, and evaluated by indexing programs. The monoclinic cell found for diethyl 4-chloro-2,2′-iminodibenzoate was a=21.332(3) Å, b=7.889(2) Å, c=10.156(2) Å, β=91.43(1)°, Z=4, space group P2 (No. 3), Pm (No. 6), or P2/m (No. 10), Dx=1.351 mg/m3. The cell found for this compound is in good agreement with the one obtained from single crystal X-ray diffractometry. The monoclinic cell found for dimethyl 4-chloro-2,2′-iminodibenzoate has the dimensions a=15.962(2) Å, b=5.151(2) Å, c=12.590(2) Å, β=98.35(1)°. Z=4, space group P2 (No. 3), Pm (No. 6), or P2/m (No. 10), Dx=2.073 mg/m3.

ChemInform Abstract: (Cyclopentadienyl)ruthenium Complexes of 3-Methoxyestrone: A High-Field NMR and X-Ray Crystallographic Study.

ChemInform ◽  
1989 ◽  
Vol 20 (29) ◽  
Author(s):  
R. M. MORIARTY ◽  
Y.-Y. KU ◽  
U. S. GILL ◽  
R. GILARDI ◽  
R. E. PERRIER ◽  
...  
Keyword(s):  
High Field ◽  
Ruthenium Complexes ◽  
X Ray ◽  
Crystallographic Study

Rietveld structural refinement of «A» type phosphostrontium carbonate hydroxyapatites

2013 ◽  
Vol 28 (S2) ◽  
pp. S409-S424 ◽  
Author(s):  
Sonia Jebri ◽  
Habib Boughzala ◽  
Ali Bechrifa ◽  
Mohamed Jemal
Keyword(s):  
Infrared Spectroscopy ◽  
Structural Model ◽  
Structural Refinement ◽  
Interatomic Distances ◽  
X Ray ◽  
Crystallographic Study ◽  
Different Temperatures ◽  
Diffraction Patterns ◽  
The One ◽  
Rietveld Structural Refinement

Phosphostrontium carbonate hydroxyapatites having the general formula Sr10(PO4)6(OH)(2-2x)(CO3)x were prepared by solid gas reaction at different temperatures in the range 0 ≤ x ≤ 1. Infrared spectroscopy investigation reveals a carbonate groups substituting hydroxyl ions. Intensity bands increasing with the carbonate amount introduced in the lattice, while the one corresponding to hydroxyl decreases until disappearance. The Rietveld refinement of the structural model using X-ray powder diffraction patterns is used to determine the substitution rate. It was quantified by the refinement of the occupancy sites affected by the substitution. The crystallographic study shows the evolution of the atomic coordinate in the apatite due to the carbonate incorporation. The variation of the main interatomic distances and the bond angles was also discussed.

(Cyclopentadienyl)ruthenium complexes of 3-methoxyestrone. A high-field NMR and x-ray crystallographic study

1989 ◽  
Vol 8 (4) ◽  
pp. 960-967 ◽  
Author(s):  
Robert M. Moriarty ◽  
Yi Yin. Ku ◽  
U. S. Gill ◽  
Richard. Gilardi ◽  
Richard E. Perrier ◽  
...  
Keyword(s):  
High Field ◽  
Ruthenium Complexes ◽  
X Ray ◽  
Crystallographic Study
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