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15N NMR spectroscopy 28—solvent effects on the 15N13C coupling constants of amides, imides, ureas and polypeptides

✍ Scribed by Hans R. Kricheldorf

Publisher
John Wiley and Sons
Year
1980
Tongue
English
Weight
671 KB
Volume
14
Category
Article
ISSN
0749-1581

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✦ Synopsis

Abstract

The ^15^N^13^C coupling constants of ^15^N‐enriched acetamide, N‐acetylglycine anilide, phthalimide, α,α′‐bisphthalimido‐p‐xylene, N‐methyl‐N′‐phenylurea, poly‐L‐alanine and poly‐L‐valine were measured in various solvents. It was found that the ^15^N^13^C coupling constants depend largely on the nature of the solvent. Increasing acidity leads to higher one‐bond and lower two‐bond coupling constants. A change of concentration does not have any influence on the ^15^N^13^C couplings while a large increase in temperature leads to a slightly lower ^1^J(NC). It is concluded that solvent effects may limit the use of ^15^N^13^C coupling constants for the elucidation of solvent‐induced conformational changes.

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