Issue 3, 2020

The reduced cohesion of homoconfigurational 1,2-diols


By a combination of linear FTIR and Raman jet spectroscopy, racemic trans-1,2-cyclohexanediol is shown to form an energetically unrivalled S4-symmetric heterochiral dimer in close analogy to 1,2-ethanediol. Analogous experiments with enantiopure trans-1,2-cyclohexanediol reveal the spectral signature of at least three unsymmetric homochiral dimers. A comparison to signal-enhanced spectra of 1,2-ethanediol and to calculations uncovers at least three transiently homochiral dimer contributions as well. In few of these dimer structures, the intramolecular OH⋯O contact present in monomeric 1,2-diols survives, despite the kinetic control in supersonic jet expansions. This provides further insights into the dimerisation mechanism of conformationally semi-flexible molecules in supersonic jets. Racemisation upon dimerisation is shown to be largely quenched under jet cooling conditions, whereas it should be strongly energy-driven at higher temperatures. The pronounced energetic preference for heterochiral aggregation of vicinal diols is also discussed in the context of chirality-induced spin selectivity.

Graphical abstract: The reduced cohesion of homoconfigurational 1,2-diols

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Article information

Article type
05 Sep 2019
26 Nov 2019
First published
12 Dec 2019
This article is Open Access
Creative Commons BY license

Phys. Chem. Chem. Phys., 2020,22, 1122-1136

The reduced cohesion of homoconfigurational 1,2-diols

B. Hartwig, M. Lange, A. Poblotzki, R. Medel, A. Zehnacker and M. A. Suhm, Phys. Chem. Chem. Phys., 2020, 22, 1122 DOI: 10.1039/C9CP04943F

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