نتایج جستجو برای: electron withdrawing

تعداد نتایج: 310077  

Navnath Gunjal Somnath Gholap,

Thiamine hydrochloride (Vitamin-B1) has been utilized as an effective biodegradable catalyst for the one pot synthesis of polyhydroquinoline derivatives via four component reaction of dimedone, aldehyde, ethylacetoacetate and ammonium acetate in ethanol under mild conditions. The method presented here offers several advantages over reported procedures in terms of environmentally benign catalyti...

A simple, highly efficient and green procedure for the condensation of o-phenylenediamines with 1, 2-dicarbonyl compounds in the presence of vitamin C, as an inexpensive organocatalyst, is described. Using this method, variety of quinoxaline derivatives with different electron releasing and electron withdrawing substituents, are produced in high to excellent yields at room temperature in ethano...

2009
Yukari IKEDA Bin Zhu YIN Akira MORI Hitoshi TAKESHITA

Heptafulvenes, fundamental members of non-alternant conjugated compounds, are known to be stabilized by introduction of electron-withdrawing substituents on the C-8 position, e.g., 8,8-dicyanoheptafulvene (1).i' The bond lengths of the exocyclic C=C of the heptafulvenes have frequently been discussed as a measure of the contribution of a dipolar form.') For example, the exocyclic C=C bond lengt...

2014
Marcelo G. Vivas Daniel L. Silva Jérémy Malinge Mohammed Boujtita Robert Zaleśny Wojciech Bartkowiak Hans Ågren Sylvio Canuto Leonardo De Boni Eléna Ishow Cleber R. Mendonca

This article reports on a comprehensive study of the two-photon absorption (2PA) properties of six novel push-pull octupolar triarylamine compounds as a function of the nature of the electron-withdrawing groups. These compounds present an octupolar structure consisting of a triarylamine core bearing two 3,3'-bis(trifluoromethyl)phenyl arms and a third group with varying electron-withdrawing str...

AliReza Kiasat Raziye Najafi Birgani,

Phosphosulfonic  acid  as a  multi  solid site  was  easily  prepared  from  the reaction of ammonium  dihydrogen phosphate with chlorosulfonic acid in CCl4and for improved  its  catalytic activity  was  supported  nano Silica was  extracted from  husk  rice  contains  about 95%  of  Silica the  size of  extracted nano silica was  determined  by  SEM  efficiency of  this solid acid in four comp...

2014
Altaf Hussain Pandith Nasarul Islam

A comprehensive theoretical study was carried out on a series of aryldimesityl borane (DMB) derivatives using Density Functional theory. Optimized geometries and electronic parameters like electron affinity, reorganization energy, frontiers molecular contours, polarizability and hyperpolarizability have been calculated by employing B3PW91/6-311++G (d, p) level of theory. Our results show that t...

Journal: :Organic & biomolecular chemistry 2012
Jinjun Shao Jingjing Chang Chunyan Chi

A series of linear and star-shaped pyrazine-containing acene molecules 1a-b, 2a-b and 3 substituted by dicarboximide groups are synthesized via condensation reactions between o-diamine and dione. High electron affinity (up to 4.01 eV) is achieved due to the introduction of an electron-deficient pyrazine moiety and the attachment of electron-withdrawing dicarboximide groups. Some of these molecu...

ژورنال: :international journal of new chemistry 0

abstract: systematic studies on the substituent effect in para substituted fe(co)4–pyridine complexes have been studied on the basis of dft quantum-chemical calculations. the following substituents were taken into consideration: no2, cn, cho, f, h, ch3, and oh. additionally, the fe–n and fe–c bonds were characterized on the basis of atoms in molecules topological analysis of electron density. i...

M Daghighi Asl P Makkipour R Ghiasi S Azmayesh

Abstract: Systematic studies on the substituent effect in para substituted Fe(CO)4–pyridine complexes have been studied on the basis of DFT quantum-chemical calculations. The following substituents were taken into consideration: NO2, CN, CHO, F, H, CH3, and OH. Additionally, the Fe–N and Fe–C bonds were characterized on the basis of Atoms in Molecules topological analysis of electron density. I...

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