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Mechanism of reactions of unsaturated ethers and thioethers.: VI. Nuclear magnetic resonance studies of acetylenic ethers and thioethers

✍ Scribed by W. Drenth; A. Loewenstein

Publisher
Elsevier Science
Year
2010
Tongue
English
Weight
450 KB
Volume
81
Category
Article
ISSN
0165-0513

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✦ Synopsis

Abstract

The position of the acetylenic hydrogen in the n.m.r. spectra of several acetylenic ethers and thioethers was measured in carbon tetrachloride, benzene and dioxan. 1‐Hexyne and 1,5‐hexadiyne were taken as reference compounds. The results prove the existence of a large charge shift in acetylenic ethers, due to resonance. There is no appreciable charge shift in acetylenic thioethers.

The rates of acetylenic hydrogen exchange in some of these compounds and in tert. butylacetylene, were also measured as a function of base concentration. The rates are highest in the sulphur compounds and lowest in tert. butylacetylene. They decrease with increasing dielectric constant of the solvent. The results are interpreted in terms of inductive effects and resonance structures of the anions.

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