Role of entropy in supramolecular photochirogenesis: enantiodifferentiating photoisomerization of cyclooctenes in chiral sensitizer-immobilized MCM-41 cavities

Maeda, Ryo; Wada, Takehiko; Kusaka, Atsushi; Mori, Tadashi; Iwamoto, Masakazu; Inoue, Yoshihisa

doi:10.1039/c1pp05087g

Cited by 4 publications

(3 citation statements)

References 21 publications

(4 reference statements)

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“…This unusual reduced entropy is rare but not unprecedented. Inoue et al demonstrated that for photoisomerization of ( Z )-cyclooctene in a mesoporous material such as MCM-41, ΔΔ S ‡ S‑R was significantly reduced from −4.5 to 0.6 cal mol –1 K –1 in methylcyclohexane, due to restricted movement of the substrate in the pores . Likewise, the reduced entropy observed in this study can be attributed to limited molecular movement resulting from frozen-state-solvent solids at low temperatures.…”

supporting

confidence: 55%

“…Inoue et al demonstrated that for photoisomerization of (Z)-cyclooctene in a mesoporous material such as MCM-41, ΔΔS ‡ S-R was significantly reduced from −4.5 to 0.6 cal mol −1 K −1 in methylcyclohexane, due to restricted movement of the substrate in the pores. 30 Likewise, the reduced entropy observed in this study can be attributed to limited molecular movement resulting from frozen-statesolvent solids at low temperatures. This is further supported by Raman spectra of the DMSO−acetone mixture used for the present reaction (see Figure S4 and the relevant discussion).…”

supporting

confidence: 51%

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Frozen Solution-Mediated Asymmetric Synthesis: Control of Enantiomeric Excess

et al. 2020

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Asymmetric List–Mannich reactions were carried out in the frozen state to afford optically active adducts in moderate-to-good chemical yields and enantiomeric excesses (ee). The frozen solution exerts critical control of ee via entropy changes, in sharp contrast to the enthalpy-driven asymmetric reactions typically observed in homogeneous solvents. This study provides new perspectives for asymmetric syntheses and an attractive alternative to conventional media.

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supporting

confidence: 55%

supporting

confidence: 51%

Frozen Solution-Mediated Asymmetric Synthesis: Control of Enantiomeric Excess

et al. 2020

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“…The coherence duration time that is appropriate to quantum logic function in DNA is provided by qualities of the DNA itself, and the crystalline nature of DNA provides a coherent stability that was intuited by Schrödinger. As occurs in DNA, the regular and precise design of the nanospace of a crystal limits the degrees of freedom upon which entropic factors such as temperature or solvation can have any effect [ 13 ], because if there is only one degree of freedom in a situation then there is zero entropy that can be induced in that situation. Thus the quantum logic in DNA by its nature involves a process of topological change in the DNA molecule, and topological quantum logic by its nature is a fault-tolerant process.…”

Section: Coherence Stabilitymentioning

confidence: 99%

Model of Biological Quantum Logic in DNA

2013

Life

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The DNA molecule has properties that allow it to act as a quantum logic processor. It has been demonstrated that there is coherent conduction of electrons longitudinally along the DNA molecule through pi stacking interactions of the aromatic nucleotide bases, and it has also been demonstrated that electrons moving longitudinally along the DNA molecule are subject to a very efficient electron spin filtering effect as the helicity of the DNA molecule interacts with the spin of the electron. This means that, in DNA, electrons are coherently conducted along a very efficient spin filter. Coherent electron spin is held in a logically and thermodynamically reversible chiral symmetry between the C2-endo and C3-endo enantiomers of the deoxyribose moiety in each nucleotide, which enables each nucleotide to function as a quantum gate. The symmetry break that provides for quantum decision in the system is determined by the spin direction of an electron that has an orbital angular momentum that is sufficient to overcome the energy barrier of the double well potential separating the C2-endo and C3-endo enantiomers, and that enantiomeric energy barrier is appropriate to the Landauer limit of the energy necessary to randomize one bit of information.

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Alkenes, alkynes, dienes, polyenes

Tsuno

2012

Photochemistry

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This chapter deals with the photochemistry of alkenes, alkynes, dienes, polyenes, and related compounds through a choice of the literature published during the period January 2010 — December 2011. Furthermore, recently many researchers are developing the photochemistry of these compounds for energy conversion, e.g. through nanotechnology applications, such as molecular devices, chemomechanics, molecular switches, etc. This chapter also covers the nanotechnology aspects that are based upon the utilization of isomerization/electrocyclization/cycloaddition reactions of the title compounds.

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Role of entropy in supramolecular photochirogenesis: enantiodifferentiating photoisomerization of cyclooctenes in chiral sensitizer-immobilized MCM-41 cavities

Cited by 4 publications

References 21 publications

Frozen Solution-Mediated Asymmetric Synthesis: Control of Enantiomeric Excess

Frozen Solution-Mediated Asymmetric Synthesis: Control of Enantiomeric Excess

Model of Biological Quantum Logic in DNA

Alkenes, alkynes, dienes, polyenes

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