کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1238065 968918 2007 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Electronic structure and solvatochromism of merocyanines: NMR spectroscopic point of view
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آنالیزی یا شیمی تجزیه
پیش نمایش صفحه اول مقاله
Electronic structure and solvatochromism of merocyanines: NMR spectroscopic point of view
چکیده انگلیسی

1H and 13C NMR spectra of two series of malononitrile-based merocyanines, which possess positive and negative solvatochromism have been in detail investigated in low polar chloroform and polar dimethyl sulfoxide (DMSO). Careful attribution of signals in spectra has been made with the help of two-dimensional NMR experiments (COSY, NOESY, HMBC, and HMQC). Hence, the dependence of merocyanines electronic structure on their chemical structure and solvent nature has been studied by this powerful method. It has been shown that there exists a good correlation between the calculated charges on carbon atoms of a polymethine chain and their chemical shifts in 13C NMR spectra. The influence of solvent polarity on bond orders for dyes with positive and negative solvatochromism is also observed. The comparison of 13C NMR spectra of merocyanines and corresponding parent ionic dyes allows to determine their sign of solvatochromism irrespectively of electronic spectra, and also to find the key atoms of chromophore whose signals in 13C NMR spectra are most informative.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy - Volume 68, Issue 1, September 2007, Pages 6–14
نویسندگان
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