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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