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.

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.

Probing Charge Delocalization in Solid State Polychromophoric Cation Radicals Using X-ray Crystallography and DFT Calculations

2018 ◽  
Vol 122 (17) ◽  
pp. 9339-9345 ◽  
Author(s):  
Lena V. Ivanova ◽  
Denan Wang ◽  
Sergey Lindeman ◽  
Maxim V. Ivanov ◽  
Rajendra Rathore
Keyword(s):  
Solid State ◽  
Dft Calculations ◽  
Charge Delocalization ◽  
X Ray ◽  
X Ray Crystallography ◽  
Cation Radicals

scholarly journals Emodin Scavenging of Superoxide Radical Includes π–π Interaction. X-Ray Crystal Structure, Hydrodynamic Voltammetry and Theoretical Studies

Antioxidants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 194 ◽  
Author(s):  
Miriam Rossi ◽  
Kelly Wen ◽  
Francesco Caruso ◽  
Stuart Belli
Keyword(s):  
Density Functional ◽  
Superoxide Radical ◽  
Therapeutic Option ◽  
Color Variation ◽  
Stable Complex ◽  
X Ray ◽  
X Ray Crystallography ◽  
Π Stacking ◽  
Vis Spectroscopy ◽  
Voltaic Cell

The naturally occurring anthraquinone emodin is found in many plants that have been part of traditional Chinese medicine (TCM) for thousands of years. Recent pharmacological studies suggest that emodin might be a valuable therapeutic option for the treatment of various diseases. We describe the antioxidant effects of emodin on the superoxide radical. Our techniques include X-ray crystallography, density functional theory (DFT), and a recently developed cyclovoltammetry improvement, the rotating ring-disk electrode (RRDE) method. X-ray results show offset π–π stacking of emodin units in the crystal, and this type of interaction is supported by the DFT, which indicates one superoxide interacting via π–π stacking with the quinone moiety, by transferring one electron to the ring, and inducing some quinone aromatization. The second superoxide seems to form a stable complex after interacting with the H(hydroxyl) in position 3 of emodin. We show that one molecule of emodin sequesters two molecules of superoxide: one forming a complex with H(hydroxyl) in position 3, and the other due to π–π oxidation of superoxide and emodin ring reduction. We conclude that emodin is a very strong antioxidant. Color variation in the voltaic cell was observed during the RRDE study. This was analyzed and explained using a mini-grid gold electrode for UV-Vis spectroscopy in the voltaic cell.

scholarly journals Near IR luminescent rare earth 3,4,5,6-tetrafluoro-2-nitrophenoxide complexes: Synthesis, X-ray crystallography and spectroscopy

Polyhedron ◽  
2008 ◽  
Vol 27 (5) ◽  
pp. 1503-1510 ◽  
Author(s):  
Youxuan Zheng ◽  
Majid Motevalli ◽  
Rendy H.C. Tan ◽  
Isaac Abrahams ◽  
William P. Gillin ◽  
...  
Keyword(s):  
Rare Earth ◽  
X Ray ◽  
X Ray Crystallography ◽  
Near Ir

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.

scholarly journals Ni(II) Butylmethyldithiocarbamate: Physico-Chemical Properties, X-Ray Crystallography, DFT and Anti-Corrosion Screening in Different Acids

2021 ◽  
Vol 16 ◽  
pp. 1-11
Author(s):  
Nor Farah Hida Othman ◽  
Noor Syafiqah Habdul Latif ◽  
Sheikh Ahmad Izzadin Sheikh Mohd Ghazali ◽  
Erna Normaya Abdullah ◽  
Nur Nadia Dzulkifli
Keyword(s):  
Fourier Transform ◽  
Chemical Properties ◽  
Attenuated Total Reflection ◽  
X Ray ◽  
Loss Analysis ◽  
X Ray Crystallography ◽  
Industrial Sectors ◽  
Physico Chemical ◽  
Vis Spectroscopy ◽  
Acid Environment

In industrial sectors, pickling and acid cleaning are mutual processes where acid solutions, such as hydrochloric acid (HCl) and sulfuric acid (H2SO4), are used to eliminate the corrosion products yielded on metal surfaces; thus, improving the performance of the machineries. However, the usage of the acid could lead to another metal deterioration. Dithiocarbamate inhibitor is defined as an organic compound that has good corrosion inhibition properties that can work as an inhibitor in an acid environment. Dithiocarbamate (DTC) assists by reducing acid reactiveness which prohibits metal dissolution in the acid. In this study, the Ni(II) N-butylmethyldithiocarbamate (Ni[BuMedtc]2) complex was synthesised by using an in-situ method and characterised by elemental analyser, attenuated total reflection Fourier transform infrared (ATR-FTIR), ultraviolet-visible (UV-Vis) spectroscopy and X-ray crystallographic study, and the chemical properties of the Ni[BuMedtc]2 complex was successfully calculated by the Discrete Fourier Transform (DFT) approach. The experimental results which were obtained through the weight-loss analysis method in two different acids – 1 M HCl and 1 M H2SO4 – indicated that the inhibition efficiency increased as the inhibitor concentration increased. The outcome showed that the Ni[BuMedtc]2 performed better as an inhibitor in 1 M HCl as compared to in1 M H2SO4 to protect the metal exterior because H2SO4 is more corrosive due to the excessive presence of H+.

scholarly journals Zn(II) Complex for Highly Sensitive and Selective Detection of Acetone at Room Temperature

2019 ◽  
Author(s):  
Mohd. Muddassir ◽  
Abdullah Alarifi ◽  
Mohammad Usman
Keyword(s):  
Room Temperature ◽  
High Selectivity ◽  
Resonance Spectroscopy ◽  
Monoclinic Space Group ◽  
Selective Detection ◽  
X Ray ◽  
X Ray Crystallography ◽  
Highly Sensitive ◽  
Vis Spectroscopy ◽  
Perchlorate Complex

A Zn(II) perchlorate complex has been prepared and characterized by single X-ray crystallography, nuclear magnetic resonance spectroscopy, thermogravimetric analysis, infrared spectroscopy, elemental analysis, and UV-vis spectroscopy. The complex crystallizes in the monoclinic space group P21/c (Z = 4) with a pentacoordinated zinc center. Interestingly, the Zn complex was found be to a potential fluorophore that could sense acetone and other ketones with high selectivity and sensitivity.

scholarly journals Synthesis and Investigation of Perfluorinated Polystannanes

2021 ◽  
Author(s):  
Miles Damion
Keyword(s):  
Tetrahedral Geometry ◽  
X Ray ◽  
Bond Angles ◽  
Network Polymers ◽  
X Ray Crystallography ◽  
Molecular Weights ◽  
Redistribution Reaction ◽  
Vis Spectroscopy ◽  
Wurtz Coupling

Two fluorinated tetraaryl stannanes, 1 and 2 were synthesized in good yields. X-ray crystallography revealed deviation from ideal tetrahedral geometry with C-Sn-C bond angles between 107.89°-112.7° for 1 and 104.69°-120.76° for 2. Dichlorides 4 and 5 were synthesized using a redistribution reaction between SnC1₄ and 1-2. These dichlorides also deviated from tetrahedral geometry with bond angles between 101.79°-128.44° for 4 and 99.23°-125.9° for 5. Polymerizaton of 4 and 5 by Wurtz coupling produced polymers 10 and 11. Absolute molecular weights in the range of 1.16 x 10⁵-2.92 x 10⁷ Da was estimated for 10 and 1.47 x 10⁵ Da for 11. UV/VIS spectroscopy gave values of 332 nm and 328 nm that are blue shifted to other polystannanes. The unexpected cleavage of a tin-aryl bond produced tin trihydrides 8 and 9. Polymerization of 8-9 produced the network polymers 12 and 13 with [wavelength]max values of 354 nm and 350 nm.

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