کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5407573 1506051 2006 11 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
An investigation of the structure and bond rotational potential of some fluorinated ethanes by NMR spectroscopy of solutions in nematic liquid crystalline solvents
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
An investigation of the structure and bond rotational potential of some fluorinated ethanes by NMR spectroscopy of solutions in nematic liquid crystalline solvents
چکیده انگلیسی
NMR spectra of 1,2-dibromo-1,1-difluoroethane and 1-bromo-2-iodo-tetrafluoroethane dissolved in nematic liquid crystalline solvents have been analysed to yield the magnitudes and signs of the scalar couplings, Jij, and total anisotropic couplings, Tij, between all the 1H, 19F, and 13C nuclei, except for those between two 13C nuclei. The values obtained for Tij in principle contain a contribution from Jijaniso, the component along the static applied magnetic field of the anisotropic part of the electron-mediated spin-spin coupling. Neglecting this contribution allows partially averaged dipolar couplings, Dij, to be extracted from the Tij, and these were used to determine the structure, orientational order, and the conformational distribution generated by rotation about the C-C bond. The values obtained are compared with the results of calculations by ab initio and density functional methods. The differences found are no greater than those obtained for similar compounds which do not contain fluorine, so that there is no definitive evidence for significant contributions from JCFaniso or JFFaniso in the two compounds studied.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Magnetic Resonance - Volume 180, Issue 2, June 2006, Pages 245-255
نویسندگان
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