Synthesis of 1,128‐Octacosahectanediol and Its Sharp Thermoresponse in Solution with Concomitant Structural Change

Saito, Nozomi; Shinozaki, Yasuhiro; Shigeno, Masanori; Mushiake, Kumiko; Yamaguchi, Masahiko

doi:10.1002/slct.201701356

Cited by 3 publications

(2 citation statements)

References 22 publications

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Section: Hysteresismentioning

confidence: 99%

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Thermal Hysteresis Involving Reversible Self-Catalytic Reactions

Yamaguchi

2021

Acc. Chem. Res.

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Conspectus Hysteresis is ubiquitous in nature and biology. It appears in ferromagnetism, ferroelectrism, traffic congestion, river sedimentation, electronics, thermoresponses, cell division, differentiation, and apoptosis. Hysteresis phenomena are beyond equilibrium and involve nonlinear, bistable, time delay, and memory events, which are described in input/output profiles by different outputs during continuous decreases and increases in input intensity. Although hysteresis profiles in these phenomena appear similar, the mechanisms underlying them are complex, and their basic understanding is desired. In this Account, I describe thermal hysteresis caused by molecules dispersed in dilute solutions containing optically active helicene oligomers, which form homo- and heterodouble helices, the cooling and heating processes of which cause different structural changes with regard to their relative concentrations. Reversible self-catalytic reactions are involved in the formation of a double helix, which catalyzes its own formation. The reactions accelerate as they progress, in contrast to ordinary reactions, which exhibit monotonic retardation as they progress. Thermal hysteresis involving reversible self-catalytic reactions exhibits notable phenomena, when various cooling/heating inputs are applied during the reaction; these phenomena are shown herein with profiles of experimental results of Δε outputs obtained by circular dichroism (CD) plotted against temperature inputs. Thermal hysteresis is discussed in terms of (1) two states of the homodouble helix and a random coil involving one reversible self-catalytic reaction and (2) three states of enantiomeric heterodouble helices and a random coil involving two reversible self-catalytic reactions. Repeated cooling and heating processes provide the same stable thermal hysteresis loops, when the initial and final high-temperature states are under equilibrium, and nonloop and unstable thermal hysteresis appears when whole the systems are beyond equilibrium. Diverse thermal hysteresis loops are obtained under different temperature change conditions for different oligomers. The mechanism of thermal hysteresis involves different macroscopic mechanisms at a fixed temperature, when the relative concentrations of substrates/products and the reaction direction differ. Microscopic mechanisms, which are shown by energy diagrams, are fixed at a temperature irrespective of cooling or heating. A comparison of thermal hysteresis loops and equilibrium curves provides distances to the metastable states on the loops from equilibrium, and reactions occur from the metastable states toward equilibrium. Notable phenomena described herein include bistability, high sensitivity to small concentration changes, equilibrium crossing, three-state one-directional structural change caused by a single heating procedure, reaction shortcuts, the memory effect on thermal history, figure-eight thermal hysteresis, chemical oscillation, stable and unstable thermal hysteresis, double-helix formation only under ...

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Section: Hysteresismentioning

confidence: 99%

“…Antifreeze proteins in fish inhibit the freezing of water. Supersaturation also involves thermal hysteresis, in which the cooling of a solution provides a homogeneous solution containing a solute above a saturation concentration (Figure c) …”

Section: Hysteresismentioning

confidence: 99%

Thermal Hysteresis Involving Reversible Self-Catalytic Reactions

Yamaguchi

2021

Acc. Chem. Res.

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Twisted Ladder Polymers: Dynamic Properties of Cylindrical Double‐Helix Oligomers with Axial Hydrophobic and Hydrophilic Groups

Yamaguchi¹

2023

Ladder Polymers

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

Sawato

Yamaguchi

2020

ChemPlusChem

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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.

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Synthesis of 1,128‐Octacosahectanediol and Its Sharp Thermoresponse in Solution with Concomitant Structural Change

Cited by 3 publications

References 22 publications

Thermal Hysteresis Involving Reversible Self-Catalytic Reactions

Thermal Hysteresis Involving Reversible Self-Catalytic Reactions

Twisted Ladder Polymers: Dynamic Properties of Cylindrical Double‐Helix Oligomers with Axial Hydrophobic and Hydrophilic Groups

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

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