نتایج جستجو برای: electron withdrawing
تعداد نتایج: 310077 فیلتر نتایج به سال:
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...
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...
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...
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...
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...
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...
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...
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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