نتایج جستجو برای: electron withdrawing

تعداد نتایج: 310077  

Journal: :Environmental science & technology 2007
Xiuping Zhu Shaoyuan Shi Junjun Wei Fanxiu Lv Huazhang Zhao Jiangtao Kong Qi He Jinren Ni

Electrochemical oxidation of some p-substituted phenols (p-nitrophenol, p-hydroxybenzaldehyde, phenol, p-cresol, and p-methoxyphenol) with electron-donating and -withdrawing substituents was studied to reveal the relationship between the structure and the electrochemical reactivity of p-substituted phenols using a boron-doped diamond electrode by voltammetry and bulk electrolysis. Voltammetric ...

2012
Lara C. Spencer Ilia A. Guzei Michael K. Ainooson James Darkwa

The angles within the benzene ring in the title compound, C(30)H(49)N(3)O, ranging from 116.34 (16) to 124.18 (16)°, reflect the presence of electron-donating and electron-withdrawing substituents. The angles at the two electron-donating tert-butyl substituents are smaller than 120°, at the electron-withdrawing eth-oxy substituent larger than 120°, and at the imine substituent equal to 119.59 (...

Journal: :Physical chemistry chemical physics : PCCP 2014
Xiaorui Liu Ming Li Rongxing He Wei Shen

An effective way to improve the efficiency of organic solar cells is to adjust the electron-withdrawing strength in donor-acceptor (D-A) copolymers. To achieve this goal, starting from previously reported polymers (PCPDT-BT and PDTPr-FBT) which are based on benzothiadiazole (BT) electron-deficient unit connected to each of two electron-rich units (cyclopentadithiophene (CPDT) and dithienopyrrol...

Journal: :Organic & biomolecular chemistry 2011
Judith Hierold Tina Hsia David W Lupton

Introduction of a β-electron withdrawing group to cycloalkanones allows facile C-C bond fragmentation. The reaction has been demonstrated with a large range of ring sizes, bearing various leaving and electron withdrawing groups, and using a variety of nitrogen and oxygen containing nucleophiles (>30 examples). The application of fragmentation products to the preparation of substituted γ-lactone...

2010
Jun Che Yulin Lam

A polymer-supported Hantzsch 1,4-dihydropyridine ester was observed to be a useful selective reducing agent for the reduction of ketimines and electron-withdrawing conjugated olefins. The rate of the reduction of electron-withdrawing conjugated olefins is dependent on the nature of the conjugated substituents and could be enhanced by microwave irradiation. The reduction of (Z)-a-cyano-bbromomet...

Journal: :The Journal of chemical physics 2011
P Andre Clayborne Olga Lopez-Acevedo Robert L Whetten Henrik Grönbeck Hannu Häkkinen

Ligand-stabilized aluminum clusters are investigated by density functional theory calculations. Analysis of Kohn-Sham molecular orbitals and projected density of states uncovers an electronic shell structure that adheres to the superatom complex model for ligand-stabilized aluminum clusters. In this current study, we explain how the superatom complex electron-counting rule is influenced by the ...

2014
Francisco Otón Raphael Pfattner Egon Pavlica Yoann Olivier Evelyn Moreno Joaquim Puigdollers Gvido Bratina Jerôme Cornil Xavier Fontrodona Marta Mas-Torrent Jaume Veciana Concepció Rovira

Journal: :Molecules 2007
Shih-Lun Lin Pei-Yu Kuo Ding-Yah Yang

This paper describes the fine-tuning of the acidichromic properties of a coumarin-containing colorant 1 by incorporation of electron-donating and electron-withdrawing substituents on the coumarin moiety. Colorant 1 can undergo two distinct and reversible color changes under both strongly acidic and basic conditions, but not in the presence of gaseous ammonia. The results indicated that the brom...

Elham Tahanpesar, Vajihe Rohani Nejad

A rapid and chemoselective method for the N-formylation of structurally diverse anilines with formic acid using nanoalumina sulfonic acid (NASA) at 70oC under solvent-free condition has been developed. The catalyst was found to be compatible with different functional groups and the formylation proceeded smoothly with anilines bearing electron withdrawing as well as electron donating substituents.

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