Deterministic and Stochastic Chiral Symmetry Breaking Exhibited by Racemic Aminomethylenehelicene Oligomers

Kushida, Yo; Sawato, Tsukasa; Shigeno, Masanori; Saito, Nozomi; Yamaguchi, Masahiko

doi:10.1002/chem.201601792

Cited by 19 publications

(25 citation statements)

References 60 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[7,12] Figure 5s hows the CD spectra for several samples of xerogels from 1 and 3,r espectively,a st he average of twentym easurements each. [13] Concerning the origin of chirality,r esultso fe xperimentss uggestt hat our case is an ew example of supramolecular physicala symmetrici nduction [14] promoted by sonication, [15] which orients the molecules during the self-assembly process owing to the generated chiral fluid motion of the bath. Nevertheless, as can be clearly observed, the sense of chirality is not reproducible.…”

Section: Circulard Ichroismmentioning

confidence: 72%

Studies on Cycloalkane‐Based Bisamide Organogelators: A New Example of Stochastic Chiral Symmetry‐Breaking Induced by Sonication

Pi-Boleda

Sans

Campos

et al. 2017

Chemistry A European J

View full text Add to dashboard Cite

Enantiomerically pure C -alkyl amides derived from cis and trans cycloalkane-1,2-dicarboxylic acids, respectively, have been synthesized and their behavior as organogelators has been investigated. These compounds include cis/trans diastereomeric cyclobutane and cyclohexane derivatives with the aim to explore the influence of the ring size as well as the relative configuration in their hierarchical self-assembly to form gels. High resolution H NMR spectroscopy studies allowed the determination of the dynamics of the gelation process in [D ]toluene and the sol-gel transition temperature. The morphology and size of the aggregates have been investigated and results have shown that, in the case of cyclobutane derivatives, the cis/trans stereochemistry is not relevant for the gelation behavior and the properties of the soft-materials obtained, but it is remarkable for cyclohexane diamides, which are better organogelators. The four compounds produce chiral aggregates despite that two of them are meso achiral molecules. We show herein that this fact is an example of stochastic symmetry breaking induced by sonication. The self-assembly of these molecules has been modelled providing information and support about the structure and the chirality of the aggregates.

show abstract

Section: Circulard Ichroismmentioning

confidence: 72%

Studies on Cycloalkane‐Based Bisamide Organogelators: A New Example of Stochastic Chiral Symmetry‐Breaking Induced by Sonication

Pi-Boleda

Sans

Campos

et al. 2017

Chemistry A European J

View full text Add to dashboard Cite

show abstract

“…As inglec ompound (P)-1 or (M)-2 in fluorobenzene( concentration 5.0 10 À4 m)d id not show any change during temperature changes (Figures S13 and S14). [13] In terms of energy,t he homogeneous-heterogeneous transition is ad ownhill chemical reactionf rom metastable random coil At ot he hetero-double-helix B, during which the metasta- The equilibrium curve was determined previously. [9] Also see Figure S10 for CD spectral changes.…”

Section: Resultsmentioning

confidence: 99%

Spatially Heterogeneous Nature of Self‐Catalytic Reaction in Hetero‐Double Helix Formation of Helicene Oligomers

et al. 2016

Self Cite

View full text Add to dashboard Cite

A 1:1 mixture of pseudoenantiomeric aminomethylenehelicene oligomers, (P)-tetramer and (M)-pentamer, in fluorobenzene show a self-catalytic phenomenon in the formation of hetero-double helices from random coils. This study visualizes the spatially heterogeneous nature of the self-catalytic reaction in dilute solution. UV/Vis imaging analysis of the mixture at 70 °C, containing random coils, exhibits a homogeneous bright area. When the solution is cooled from 70 to 30 °C and held at that temperature, dark domains of approximately 1 mm in size appear, which move approximately at a rate of 1 mm min . The dark domains indicate that weaker UV/Vis absorption results from the formation of hetero-double helices, which is supported by circular dichroism (CD) imaging experiments. Then a homogeneous mixture is regenerated upon heating to 55 °C, as shown by CD imaging. Under self-catalytic conditions, a homogeneous solution spontaneously changed to a heterogeneous solution in the process of hetero-double-helix formation.

show abstract

“…Described here is chiral symmetry breaking of racemic (P)-5/(M)-5, which occurs during hetero-double-helix formation and their molecular self-assembly ( Figure 24b). [50] An advantage of these systems is that properties of (P)-5/(M)-4 and (P)-5/(M)-5 can be compared, because (P)-5/(M)-4 and (P)-5/(M)-5 are very similar in structure. (P)-5/(M)-5 in toluene was heated to 90°C to form 2A(A) solution, which was optically inactive (Figure 36a).…”

Section: Racemic Aminomethylenehelicene Oligomersmentioning

confidence: 99%

Synthetic Chemical Systems Involving Self‐Catalytic Reactions of Helicene Oligomer Foldamers

Sawato

Yamaguchi

2020

ChemPlusChem

Self Cite

View full text Add to dashboard Cite

Self‐catalysis is defined as catalysis by a product of a chemical reaction, that causes a significant increase in reaction rate in terms of the progress of the reaction. When a self‐catalytic reaction is involved in a reversible nonequilibrium‐to‐equilibrium chemical reaction, notable kinetic phenomena appear including sigmoidal kinetics, the seeding effect, thermal hysteresis, and chiral symmetry breaking. The nature of self‐catalytic reactions is characterized by microscopic mechanisms involving pathways of molecular structural changes and by macroscopic mechanisms involving molecular flux. Reversible self‐catalytic reactions, which exhibit notably high sensitivity to environmental changes, are also observed. In this Review, reversible self‐catalytic reactions of helicene oligomer foldamers during formation of homo‐ and hetero‐double‐helices are discussed, which exhibit the properties outlined above.

show abstract

Deterministic and Stochastic Chiral Symmetry Breaking Exhibited by Racemic Aminomethylenehelicene Oligomers

Cited by 19 publications

References 60 publications

Studies on Cycloalkane‐Based Bisamide Organogelators: A New Example of Stochastic Chiral Symmetry‐Breaking Induced by Sonication

Studies on Cycloalkane‐Based Bisamide Organogelators: A New Example of Stochastic Chiral Symmetry‐Breaking Induced by Sonication

Spatially Heterogeneous Nature of Self‐Catalytic Reaction in Hetero‐Double Helix Formation of Helicene Oligomers

Synthetic Chemical Systems Involving Self‐Catalytic Reactions of Helicene Oligomer Foldamers

Contact Info

Product

Resources

About