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1 H and 13 C NMR aromatic solvent‐induced shifts of n ‐alkanes
Author(s) -
Nikki Kunio
Publication year - 1990
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1260280502
Subject(s) - chemistry , methylene , chemical shift , solvent , alkane , nmr spectra database , carbon 13 nmr , carbon 13 , proton nmr , solvent effects , nuclear magnetic resonance spectroscopy , crystallography , carbon fibers , spectral line , stereochemistry , hydrocarbon , organic chemistry , physics , materials science , quantum mechanics , astronomy , composite number , composite material
The 1 H and 13 C NMR spectra of a series of n ‐alkanes (C 5 ‐C 32 ) were measured in CCl 4 , CDCl 3 , C 6 D 6 , C 6 H 5 Cl and C 6 D 5 CD 3 and the aromatic solvent‐induced shifts (ASIS) are discussed. The chemical shifts of the inner methylene protons show a steady downfield shift as the carbon number of the n ‐alkane increases, while the shifts of the methyl protons are smaller than those of the inner methylene protons in aromatic solvents. The ASIS of the outer carbons are larger than those of the inner carbons up to the sixth carbon from the end. The ASIS of the sixth and further inner carbons of the short chains are larger than those of the long chains. These results suggest that n ‐alkanes have a folded structure in aromatic solvents and that the degree of folding increases with increasing chain length.