نتایج جستجو برای: electrophilicity

تعداد نتایج: 386  

Journal: :Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy 2002
Salim Y Hanna Moafaq Y Shandala Salim M Khalil

A series of 1-arylallyl alcohols were prepared and its OH stretching frequencies measured in 20 different non-HBD solvents at room temperature. It is noticed that the observed stretching bands were highly sensitive to the nature of the solvents. Multiple parameter equations were applied to investigate the solvent effects on the O-H stretching frequency. The most significant solvent parameters w...

2017
Guo-Xing Li Cristian A. Morales-Rivera Fang Gao Yaxin Wang Gang He Peng Liu Gong Chen

We report a unified photoredox-catalysis strategy for both hydroxylation and amidation of tertiary and benzylic C–H bonds. Use of hydroxyl perfluorobenziodoxole (PFBl–OH) oxidant is critical for efficient tertiary C–H functionalization, likely due to the enhanced electrophilicity of the benziodoxole radical. Benzylic methylene C–H bonds can be hydroxylated or amidated using unmodified hydroxyl ...

Journal: :The journal of physical chemistry. A 2003
Eduardo Chamorro Pratim K Chattaraj Patricio Fuentealba

Some exact conditions for the extremals of the electrophilicity index, ω = μ(2)/2η (Parr, R. G.; von Szentpály, L.; Liu, S. J. Am. Chem. Soc. 1999, 121, 1922), along an arbitrary reaction coordinate, have been carefully examined. Implications within the widely used finite difference approximation for the density-functional based reactivity descriptors, their relationship with the maximum hardne...

2016
Norihiro Tada Daniel J. Jansen Matthew P. Mower Megan M. Blewett Jeffrey C. Umotoy Benjamin F. Cravatt Dennis W. Wolan Ryan A. Shenvi

We describe a general method to synthesize the iminium tetrahydrothiophene embedded in the dimeric Nuphar alkaloids. In contrast to prior studies, the sulfur atom of the thiaspirane pharmacophore is shown to be electrophilic. This α-thioether reacts with thiophenol or glutathione at ambient temperature to cleave the C-S bond and form a disulfide. Rates of conversion are proportional to the corr...

Journal: :Journal of the Turkish Chemical Society, Section A: Chemistry 2016

Journal: :Chemical communications 2011
Sami Lakhdar Herbert Mayr

Electrophilic substitution of pyrroles by α,β-unsaturated iminium ions is slow in acetonitrile when only weakly basic counterions are present. When the reactions are carried out in the presence of KCF(3)CO(2), fast deprotonation of the intermediate σ-adducts occurs, and the rate constant for the rate-determining CC bond-forming step can be predicted from the electrophilicity parameter E of the ...

Journal: :Journal of molecular modeling 2013
Patricio Fuentealba Carlos Cárdenas

Using an exponential model for the variation in energy with respect to the number of electrons it is shown that, within the model, the hardness, softness, electrophilicity and other global parameters connected to higher order derivatives follow an equalization principle after a molecule is formed from two separated species. Two generalizations of the model are also discussed, one of which prese...

Journal: :Molecules 2016
Luis R Domingo Mar Ríos-Gutiérrez Patricia Pérez

Theoretical reactivity indices based on the conceptual Density Functional Theory (DFT) have become a powerful tool for the semiquantitative study of organic reactivity. A large number of reactivity indices have been proposed in the literature. Herein, global quantities like the electronic chemical potential μ, the electrophilicity ω and the nucleophilicity N indices, and local condensed indices...

Journal: :Journal of the American Chemical Society 2003
Luis G Arnaut Alberto A C C Pais Sebastião J Formosinho Monica Barroso

We calculate transition-state energies of atom-transfer reactions from reaction energies, electrophilicity indices, bond lengths, and vibration frequencies of the reactive bonds. Our calculations do not involve adjustable parameters and uncover new patterns of reactivity. The generality of our model is demonstrated comparing the vibrationally adiabatic barriers obtained for 100 hydrogen-atom tr...

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