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Stereochemistry of crown ethers. IV—1H/13C NMR spectroscopic study of the solution structure of some bis(benzocrown ethers)

✍ Scribed by S. Stoss; E. Kleinpeter; H.-J. Holdt

Publisher
John Wiley and Sons
Year
1991
Tongue
English
Weight
444 KB
Volume
29
Category
Article
ISSN
0749-1581

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✦ Synopsis

Abstract

The ^1^H and ^13^C NMR spectra of some bis(benzocrown ethers) were recorded and assigned by means of ^1^H/^13^C HETCOR spectroscopy, heteronuclear selective decoupling experiments and the refocused INEPT experiment optimized for long‐range ^1^H, ^13^C coupling constants. It is shown that the efficiency of the so‐called ‘biscrown effect’ is dependent on the radii of the alkali metal ions. Long‐range ^1^H, ^13^C coupling constants, high‐field shifts within γ‐fragments in the ^13^C NMR spectra and NOEs from 2D‐NOESY spectra are discussed with respect to both the configuration and the preferred conformation of the studied compounds.

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