کد مقاله کد نشریه سال انتشار مقاله انگلیسی ترجمه فارسی نسخه تمام متن
5134399 1378852 2017 5 صفحه PDF سفارش دهید دانلود کنید
عنوان انگلیسی مقاله
Secondary kinetic deuterium isotope effects. The CC cleavage of labeled tetramethylethylenediamine radical cations-Who gets to keep the electron?
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آنالیزی یا شیمی تجزیه
پیش نمایش صفحه اول مقاله
Secondary kinetic deuterium isotope effects. The CC cleavage of labeled tetramethylethylenediamine radical cations—Who gets to keep the electron?
چکیده انگلیسی

The simple cleavage of the C-C bond in tetramethylethylenediamine molecular ions yields two fragments that are identical but for the positions of the charge and radical; nonetheless, the reactions of deuterium labeled analogs are accompanied by substantial secondary kinetic isotope effects. The underlying transition state zero-point vibrational energy differences depend particularly on the properties of the incipient radicals rather than on those of the charge-retaining products. The α-secondary effects arise primarily from vibrations related to deformation of the product -CH2N- and -CD2N- groups when the reactant is labeled at the central C-C bond, whereas CH/CD stretching vibrations are the origin of the γ-secondary effects observed for reactants with labeled methyl groups. These zero-point energy differences are mainly due to hyperconjugative interactions (Bohlmann shifts) and do not reflect bonding changes in the transition state; the secondary isotope effects on the dissociation of protonated amine dimers have a similar origin.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: International Journal of Mass Spectrometry - Volume 413, February 2017, Pages 92-96
نویسندگان
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