Search results for "Electrophilicity"
showing 5 items of 5 documents
Measuring the Relative Reactivity of the Carbon-Hydrogen Bonds of Alkanes as Nucleophiles
2018
We report quantitative measurements of the relative reactivities of a series of C-H bonds of gaseous or liquid CnH2n+2 alkanes (n = 1-8, 29 different C-H bonds) towards insitu generated electrophiles (copper, silver, and rhodium carbenes), with methane as the reference. This strategy surpasses the drawback of previous model reactions of alkanes with strong electrophiles suffering from C-C cleavage processes, which precluded direct comparison of the relative reactivities of alkane C-H bonds.
A Theoretical Study of the Relationship between the Electrophilicity ω Index and Hammett Constant σp in [3+2] Cycloaddition Reactions of Aryl Azide/A…
2016
The relationship between the electrophilicity ω index and the Hammett constant σp has been studied for the [2+3] cycloaddition reactions of a series of para-substituted phenyl azides towards para-substituted phenyl alkynes. The electrophilicity ω index—a reactivity density functional theory (DFT) descriptor evaluated at the ground state of the molecules—shows a good linear relationship with the Hammett substituent constants σp. The theoretical scale of reactivity correctly explains the electrophilic activation/deactivation effects promoted by electron-withdrawing and electron-releasing substituents in both azide and alkyne components.
Effect of electron-withdrawing substituents on the electrophilicity of carbonyl carbons
2005
Indexación: Scopus The substituent effects on the carbonyl carbon atom for a series of twelve substituted phenyl acetates have been rationalized using a global electrophilicity index. This index is linearly correlated with the experimental reaction rate coefficients. We found that, in contrast to the proposed interpretation based on experimental 13C NMR chemical shifts and ground state destabilization calculations, the electrophilicity of carbonyl compounds increases due to the effect promoted by electron-withdrawing groups in these systems. https://www.sciencedirect.com/science/article/pii/S0040402004018046?via%3Dihub
Applications of the Conceptual Density Functional Theory Indices to Organic Chemistry Reactivity.
2016
Indexación: Web of Science 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 like the electrophilic and nucleophilic Parr functions, as the most relevant indices for the study of organic reactivity, are discussed. http://www.mdpi.com/1420-3049/21/6/748
Understanding the regioselectivity in hetero Diels–Alder reactions. An ELF analysis of the reaction between nitrosoethylene and 1-vinylpyrrolidine
2013
[EN] The regioselectivity in the hetero Diels-Alder reaction between nitrosoethylene 1 and 1-vinylpyrrolidine 2 has been studied by a comparative ELF bonding analysis along the IRC of the endo/ortho and endo/meta regioisomeric channels at the B3LYP/6-31G*. level. Along the most favorable endo/ortho regioisomeric channel, the C-C sigma bond is first formed by coupling of two pseudoradical centers located at the most electrophilic carbon of 1 and the most nucleophilic center of 2. Formation of these relevant pseudoradical centers, which depend on the total charge transfer process along the polar reaction, and not on the approach mode of each reagent, is well characterized by analysis of the a…