Synthesis of Ar-BIAN Ligands (Ar-BIAN = Bis(aryl)acenaphthenequinonediimine) Having Strong Electron-Withdrawing Substituents on the Aryl Rings and Their Relative Coordination Strength toward Palladium(0) and -(II) Complexes

2002 ◽  
Vol 21 (14) ◽  
pp. 2950-2957 ◽  
Author(s):  
Michela Gasperini ◽  
Fabio Ragaini ◽  
Sergio Cenini
Keyword(s):  
Strong Electron ◽  
Relative Coordination ◽  
Electron Withdrawing Substituents

Asymmetric Hydrocyanation of a Range of Aromatic and Aliphatic Aldehydes

1988 ◽  
Vol 41 (11) ◽  
pp. 1697 ◽  
Author(s):  
BR Matthews ◽  
WR Jackson ◽  
GS Jayatilake ◽  
C Wilshire ◽  
HA Jacobs
Keyword(s):  
Hydrogen Cyanide ◽  
Enantiomeric Excess ◽  
Basic Catalyst ◽  
Strong Electron ◽  
Aliphatic Aldehydes ◽  
Aryl Aldehydes ◽  
Heterocyclic Aldehydes ◽  
Electron Withdrawing Substituents

A range of aryl, alkyl and heterocyclic aldehydes have been treated with hydrogen cyanide in the presence of the 'Inoue' catalyst, (R,R)- or (S,S)-cyclo [phenylalanylhistidyl]. Most aryl aldehydes with electron-donating substituents in the m- or p-positions give high enantiomeric excess (e.e.) values (≥80%) but aryl aldehydes with strong electron-withdrawing substituents gave moderate e.e. values (≤50%). These moderate values are believed to be due to partial racemization of the product cyanohydrins in the presence of the mildly basic catalyst. In contrast to the reactions of aryl aldehydes , reactions of alkyl aldehydes and of ketones gave low e.e. values (≤30%) and an explanation is proposed.

Antioxidant properties of ethenyl indole: DPPH assay and TDDFT studies

2020 ◽  
Vol 44 (21) ◽  
pp. 8960-8970 ◽  
Author(s):  
Jagdeep Kumar ◽  
Naresh Kumar ◽  
Nitin Sati ◽  
Prasanta Kumar Hota
Keyword(s):  
Antioxidant Activity ◽  
Vitamin E ◽  
Antioxidant Activities ◽  
Antioxidant Properties ◽  
Dependent Manner ◽  
Dpph Assay ◽  
Strong Electron ◽  
Electron Withdrawing Substituents

Ethenyl indole exhibits antioxidant activity in a substituent dependent manner. Ethenyls bearing strong electron withdrawing substituents show weak or no antioxidant activities, whereas ethenyls with electron donating substituents exhibit antioxidant properties comparable to vitamin E.

Highly efficient anion transport mediated by 1,3-bis(benzimidazol-2-yl)benzene derivatives bearing electron-withdrawing substituents

2016 ◽  
Vol 14 (35) ◽  
pp. 8232-8236 ◽  
Author(s):  
Chen-Chen Peng ◽  
Meng-Jia Zhang ◽  
Xiao-Xiao Sun ◽  
Xiong-Jie Cai ◽  
Yun Chen ◽  
...  
Keyword(s):  
Anion Transport ◽  
Benzene Derivatives ◽  
Strong Electron ◽  
Highly Efficient ◽  
Electron Withdrawing Substituents

1,3-Bis(benzimidazol-2-yl)benzene derivatives bearing strong electron-withdrawing substituents were found to exhibit highly efficient anion transport.

Syntheses and Substituent Effects on the Properties of Unsymmetrical Photochromic Diarylethenes Bearing a Benzothiophene Unit

2009 ◽  
Vol 62 (5) ◽  
pp. 464 ◽  
Author(s):  
Shouzhi Pu ◽  
Min Li ◽  
Gang Liu ◽  
Zhanggao Le
Keyword(s):  
Crystalline Phase ◽  
Substituent Effects ◽  
Cyclic Voltammogram ◽  
X Ray Diffraction ◽  
Strong Electron ◽  
X Ray ◽  
Remarkable Effect ◽  
Photostationary State ◽  
Closed Ring ◽  
Electron Withdrawing Substituents

Photochromic unsymmetrical diarylethenes 1a–5a that bear different electron-donating or electron-withdrawing substitutes have been synthesized, and the structures of 2a–5a determined by single-crystal X-ray diffraction analysis. Substituent effects on their optoelectronic properties, including photochromism, fluorescence, and electrochemical properties are investigated in detail. The strong electron-donating substituents have effective contributions to the absorption maxima of the closed-ring isomers and the molar coefficients, whereas the electron-withdrawing substituents can shift significantly the absorption maxima of the diarylethenes to a longer wavelength and increase their cyclization quantum yield. Diarylethenes 2, 3, and 4 show good photochromism both in solution and in the single crystalline phase. However, diarylethenes 5 shows no photochromism in the crystalline phase. Diarylethenes 1, 2, and 3 exhibit good fluorescent switching upon alternating irradiation with UV and visible light, and their fluorescent conversions in the photostationary state are all larger than 80% in hexane. In addition, cyclic voltammogram tests show that different electron-donating and electron-withdrawing substituents have a remarkable effect on the electrochemical behaviours of these diarylethenes.

scholarly journals EFFECT OF SUBSTITUTED BENZANILIDES ADDITIVES ON THE SPEED OF CATALYZED BY TETRABUTOXYTIITANE AND POLYBUTOXYTIТANATE REACTION OF ANILINE WITH BENZOIC ACID

2019 ◽  
Vol 85 (1) ◽  
pp. 19-31
Author(s):  
Leon Yakovlevich Shteinberg
Keyword(s):  
Benzoic Acid ◽  
Carbonyl Group ◽  
Titanium Atom ◽  
Partial Hydrolysis ◽  
Strong Electron ◽  
Reaction Rate Constants ◽  
Straight Line ◽  
Conjugate Acid ◽  
Urgent Task ◽  
Electron Withdrawing Substituents

The catalytic synthesis of benzanilide by the interaction of benzoic acid with aniline is an important model reaction of direct catalytic amidation that has been intensively developed recently in the field  of the concept of «green chemistry», and its study is an urgent task.      In the framework of solving this problem the effect of the final product - benzanilide, and its substituted on catalysis by tetrabutoxytitanium and its partial hydrolysis products (polybutoxytitanates) was studied. With an increase in the concentration of the preliminary addition of benzanilide, the initial rate of catalytic interaction of benzoic acid with aniline decreases monotonically.      Benzanilide itself does not catalyze the amidation process, does not hydrolyze under reaction conditions by water, and does not undergo other changes in the reaction mass.      The kinetics of the formation of benzanylide in the presence of additives of a number of substituted benzanilides, containing electron-withdrawing substituents, showed higher values ​​of the reaction rate constants as compared to that for the formation of benzanilide in the absence of any additives. This suggests the presence of two routes of catalysis: the coordination route (polarization of the carbonyl group of the benzoic acid due to the interaction with the atom of titanium) and acid route. The latter can be associated with the formation of complexes due to the coordination of the titanium atom of the catalyst with the carbonyl group of the substituted benzanilide, the appearance of a relatively acidic NH=group and catalysis of conjugate acid: the titanium-containing catalyst + the corresponding substituted benzanilide.      The formation of such a catalytic complex, by the example of a pair of benzanilide + tetrabutoxytitanium, was confirmed by the NMR 1H spectroscopy method.      Catalysis of aniline acylation with benzoic acid in the presence of additions meta= and para=substituted benzanilides correlates well with the Hammett equation with two straight line segments with ρ=0.478 and ρ=-0.235, with a maximum, indicating a different effect of substituted benzanilides containing electron-donating and strong electron-withdrawing substitutes on the complexation with tetrabutoxytitanium and polybutoxytitanium and the change in their catalytic activity.      The decrease in the rate of the catalytic formation of benzanilide is especially pronounced with the addition of ortho=substituted benzanilides, containing strong electron-withdrawing substituents, which at the same time have a high steric effect.

Evidence for Strong Electron-Electron Correlations in (MTPP)1-x (MTPA)X (TCNQ)2

1982 ◽  
Vol 85 (1) ◽  
pp. 225-231
Author(s):  
G. Croteau ◽  
Amir Lakhani ◽  
N. K. Hota
Keyword(s):  
Electron Correlations ◽  
Strong Electron

Photocatalytic Alkylation of Pyrroles and Indoles with α-Diazo Esters

2019 ◽  
Author(s):  
Łukasz Ciszewski ◽  
Jakub Durka ◽  
Dorota Gryko
Keyword(s):  
Aromatic Compounds ◽  
Reaction Pathway ◽  
Alkylating Agents ◽  
Catalytic Amount ◽  
Radical Formation ◽  
Reaction Selectivity ◽  
Diazo Esters ◽  
Electron Withdrawing Substituents

This article describes direct photoalkylation of electron-rich aromatic compounds with diazo compoiunds. C-2 alkylated indoles and pyrroles are obtained with good yields even though the photocatalyst (Ru(bpy)3Cl2) loading is as low as 0.075 mol %. For substrates bearing electron-withdrawing substituents the addition of a catalytic amount of N,N-dimethyl-4-methoxyaniline is required. Both EWG-EWG and EWG-EDG substituted diazo esters are suitable as alkylating agents. The reaction selectivity and mechanistic experiments suggest that carbenes/carbenoid intermediates are not involved in the reaction pathway, instead radical formation is proposed.

Electron Donation by Low-Crystalline Ba-La-Ce Oxygen-Deficient Composite Oxide Accumulating on Ru Nanoparticles for Ammonia Synthesis under Mild Conditions

2019 ◽  
Author(s):  
Katsutoshi Sato ◽  
Shin-ichiro Miyahara ◽  
Yuta Ogura ◽  
Kotoko Tsujimaru ◽  
Yuichiro Wada ◽  
...  
Keyword(s):  
Ammonia Synthesis ◽  
Bond Cleavage ◽  
Synthesis Process ◽  
Strong Electron ◽  
Mild Conditions ◽  
Ru Nanoparticles ◽  
Rate Determining Step ◽  
Highly Active ◽  
Composite Oxides ◽  
Low Crystalline

<p>To mitigate global problems related to energy and global warming, it is helpful to develop an ammonia synthesis process using catalysts that are highly active under mild conditions. Here we show that the ammonia synthesis activity of Ru/Ba/LaCeO<i><sub>x</sub></i> pre-reduced at 700 °C is the highest reported among oxide-supported Ru catalysts. Our results indicate that low crystalline oxygen-deficient composite oxides, which include Ba<sup>2+</sup>, Ce<sup>3+</sup> and La<sup>3+</sup>, with strong electron-donating ability, accumulate on Ru particles and thus promote N≡N bond cleavage, which is the rate determining step for ammonia synthesis.</p>

Electron Donation by Low-Crystalline Ba-La-Ce Oxygen-Deficient Composite Oxide Accumulating on Ru Nanoparticles for Ammonia Synthesis under Mild Conditions

2019 ◽  
Author(s):  
Katsutoshi Sato ◽  
Shin-ichiro Miyahara ◽  
Yuta Ogura ◽  
Kotoko Tsujimaru ◽  
Yuichiro Wada ◽  
...  
Keyword(s):  
Ammonia Synthesis ◽  
Bond Cleavage ◽  
Synthesis Process ◽  
Strong Electron ◽  
Mild Conditions ◽  
Ru Nanoparticles ◽  
Rate Determining Step ◽  
Highly Active ◽  
Composite Oxides ◽  
Low Crystalline

<p>To mitigate global problems related to energy and global warming, it is helpful to develop an ammonia synthesis process using catalysts that are highly active under mild conditions. Here we show that the ammonia synthesis activity of Ru/Ba/LaCeO<i><sub>x</sub></i> pre-reduced at 700 °C is the highest reported among oxide-supported Ru catalysts. Our results indicate that low crystalline oxygen-deficient composite oxides, which include Ba<sup>2+</sup>, Ce<sup>3+</sup> and La<sup>3+</sup>, with strong electron-donating ability, accumulate on Ru particles and thus promote N≡N bond cleavage, which is the rate determining step for ammonia synthesis.</p>

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