Issue 45, 2019

Proximate stochastic chiral symmetry breaking is mechanically tunable: formation of enantiomeric hetero-double-helices and aggregates from racemic oxymethylenehelicene oligomers

Abstract

A mixture of oxymethylenehelicene (P)-hexamer and (M)-hexamer in solution exhibited chiral symmetry breaking, which was induced by mechanical stirring, during the formation of enantiomeric hetero-double-helices and their aggregates. A racemic 50 : 50 mixture was heated to 90 °C to form a dissociated state, and then cooled to 25 °C. Mechanical stirring with a magnetic stirrer at 2000 rpm for 100 h resulted in the exhibition of a strong negative Cotton effect at 322 nm. Repeated experiments provided negative Cotton effects, which is due to the deterministic chiral symmetry breaking. No change in the Cotton effect occurred in the absence of stirring. The (P)-hexamer to (M)-hexamer mixing molar fraction was varied, and a positive Cotton effect appeared at molar fractions between 40 : 60 and 46 : 54 and a negative Cotton effect at molar fractions between 48 : 52 and 60 : 40, which was reversed at 47 : 53. The slight deviation of symmetry from that at 50 : 50 was termed proximate stochastic chiral symmetry breaking. The process of chiral symmetry breaking could be tuned by varying the procedures of mechanical stirring and mixing procedures for solutions of (P)-hexamer and/or (M)-hexamer.

Graphical abstract: Proximate stochastic chiral symmetry breaking is mechanically tunable: formation of enantiomeric hetero-double-helices and aggregates from racemic oxymethylenehelicene oligomers

Supplementary files

Article information

Article type
Paper
Submitted
02 Aug 2019
Accepted
29 Oct 2019
First published
30 Oct 2019

Phys. Chem. Chem. Phys., 2019,21, 25406-25414

Proximate stochastic chiral symmetry breaking is mechanically tunable: formation of enantiomeric hetero-double-helices and aggregates from racemic oxymethylenehelicene oligomers

T. Sawato, N. Saito and M. Yamaguchi, Phys. Chem. Chem. Phys., 2019, 21, 25406 DOI: 10.1039/C9CP04299G

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements