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Updated: May 13, 2026
Preparation of a Corannulene-functionalized Hexahelicene by Copper(I)-catalyzed Alkyne-azide Cycloaddition of Nonplanar Polyaromatic Units
Published on: September 18, 2016
Conformations and CH/π interactions in aliphatic alkynes and alkenes
Alf Holme1, Knut J Børve, Leif J Sæthre
1Department of Chemistry, University of Bergen, NO-5007 Bergen, Norway.
Abstract:
The carbon 1s photoelectron spectra of a series of aliphatic alkynes and alkenes that have the possibility of possessing two or more conformers have been recorded with high resolution. The two conformers of 2-hexyne and 4-methyl-1-pentyne, anti and gauche, have been identified and quantified from an analysis of their carbon 1s photoelectron spectra, yielding 30 ± 5% and 70 ± 6% anti conformers, respectively. In the case of 1-hexyne, the photoelectron spectrum is shown to provide partial information on the distribution of conformers. Central to these analyses is a pronounced ability of the C1s photoemission process to distinguish between conformers that display weak γ-CH/π hydrogen bonding and those that do not. For the corresponding alkene analogs, similar analyses of their C1s photoelectron spectra do not lead to conclusive information on the conformational equilibria, mainly because of significantly smaller chemical shifts and higher number of conformers compared with the alkynes.
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