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Two-dimensional NMR studies of polyene systems. II. β-carotene

✍ Scribed by Jacques Wernly; JÜRgen Lauterwein

Publisher: John Wiley and Sons
Year: 1985
Tongue: English
Weight: 705 KB
Volume: 23
Category: Article
ISSN: 0749-1581
DOI: 10.1002/mrc.1260230308

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✦ Synopsis

Two-dimensional NMR results are presented for B-carotene in chloroform. J-resolved 'H NMR spectroscopy allows the accurate determination of the chemical shifts and coupling constants for the ole6nic protons. In order to obtain su5uent signal intensity in the projection spectrum for the H-C-7, H-C-10 and H-C-14 protons, spin decoupling of the long-range coupled methyl and methylene protons was necessary. 'H,=C chemical shift-correlated NMR spectroscopy gave a relationship between the directly bonded ole6nic CH pairs. Cross-sections through each -C chemical shift allowed the assignment of the carbon resonances. Simulation of the cross-sections was possible when the 180" carbon pulse was removed in the standard pulse sequence. It is shown that, under these conditions, the cross-sections correspond to partial =CH satellite spectra.

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