نتایج جستجو برای: electrophilicity
تعداد نتایج: 386 فیلتر نتایج به سال:
Theoretical calculations were carried out to understand the effect of annulation on the electronic and ligand properties of boron substituted N-heterocyclic carbenes (B-NHCs). Annulation results in a decrease in stability as indicated by the calculated values of singlet-triplet separations and stabilization energies as well as HOMO-LUMO gaps. Annulated B-NHCs are found to be weaker σ-donors but...
Purpurin is a major anthraquinone present in the roots of Rubia cordifolia (madder). known to activate Nrf2 (Nuclear transcription factor erythroid 2-related 2) EpRE (electrophile responsive element) mediated gene expression as potential beneficial effect. This study aimed elucidate balance between electrophilicity or pro-oxidant activity purpurin underlying induction. For this, activation with...
The reference electrophilicity and nucleophilicity scales established at the B3LYP/6-31G(d) level are herein extended by least squares regressions to most common DFT computational methods used in theoretical organic chemistry studies, including B3LYP, MPWB1K, M062-X, ωB97x-D, combination with basis sets of type 6-31G 6-311G different degrees polarization diffuse functions. Excellent linear corr...
ABSTRACT The electrophilicity of (E)-2-aryl-1-cyano-1-nitroethenes is not sufficient to induce a zwitterionic course of their [4+2] cycloaddition to cyclopentadiene. The one-step mechanism of these reactions is indicated by the activation parameters, and the substituent and solvent effects on the reaction. GRAPHICAL ABSTRACT
Dendritic diarylcarbenium ions exhibited sufficient electrophilicity to react with unfunctionalized polystyrenes. The polymers obtained by the reaction of the first and the second generation dendritic diarylcarbenium ions with polystyrenes were well characterized by MALDI-TOF MS and SEC-MALLS analyses and observed by AFM.
Vinyl cations I+, of the structure R^C^CR" (I+: R' = R" = anisyl; R' = phenyl.R" = anisyl. I*: R' — methyl.R" = anisyl) were generated by flash photolysis of corresponding bromides. Lifetime measurements yielded the following: substitution of aromatic groups in 2-position by methyl groups largely improved the electrophilicity of the vinyl cations. The nucleophilicity of typical compounds (keton...
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