Chiroptical Molecular Switches

Feringa, Ben L.; Delden, Richard A. van; Wiel, Matthijs K. J. ter

doi:10.1002/3527600329.ch5

Cited by 95 publications

(118 citation statements)

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“…Compound 6: A mixture of 1,3-bis(4'-hydroxyphenylazo)benzene [40] (101 mg, 0.32 mmol), (S)-(+)-benzylglycidyl ether (0.11 mL, 0.70 mmol) and potassium carbonate (500 mg, 3.6 mmol) in DMF (2 mL) was refluxed for 48 h. After cooling to room temperature, the mixture was partitioned between CHCl 3 and saturated NH 4 Cl. The aqueous layer was washed twice with CHCl 3 and the combined organic fractions were dried over Na 2 SO 4 . The residue was purified by column chromatography on silica gel (petroleum ether/ethyl acetate 65:35 as the eluant) to afford 6 as a yellow-orange solid in 82 % yield.…”

Section: Compoundmentioning

confidence: 99%

“…The residue was partitioned between CHCl 3 and water. The aqueous layer was washed twice with CHCl 3 and the combined organic fractions were dried over Na 2 SO 4 …”

Section: Compoundmentioning

confidence: 99%

“…[4] Several switching systems also work in processable media such as polymers and liquid crystals. [5] In the field of liquid crystals, chiral photochemical switches are of interest for two reasons: they induce the formation of cholesteric phases in nematic hosts, and can allow the helical pitch to be controlled by their photochemical isomerisation.…”

Section: Introductionmentioning

confidence: 99%

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The Control of the Cholesteric Pitch by Some Azo Photochemical Chiral Switches

Pieraccini

Gottarelli

Labruto

et al. 2004

Chemistry A European J

115

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A few chiral azo compounds, which undergo reversible photochemical switching, are presented. Of these, the most interesting contain the binaphthyl moiety and belong to the C2 (derivatives 1 and 2) or C1 symmetry group (derivatives 3 and 4). These binaphthyl compounds display intense CD and high beta values. Photochemical switching has profound effects on both the CD and beta values of these compounds; in the case of compound 3, the sign of beta changes upon isomerisation. Compound 2 has, to our knowledge, the highest beta of the switches reported in the literature and also seems the most interesting owing to its fast response to photochemical stimuli. Nematic phases can be transformed into cholesteric phases with reflection bands in the visible region by doping with reasonable amounts of 1 and 2. The reflection colours can be changed reversibly by photoisomerisation of the switches. Thermal reversion of the colourless UV photostationary state to the green isomeric EE state or to intermediate coloured states is temperature dependent. This can allow the thermal history of a sample to be traced.

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Section: Compoundmentioning

confidence: 99%

“…The residue was partitioned between CHCl 3 and water. The aqueous layer was washed twice with CHCl 3 and the combined organic fractions were dried over Na 2 SO 4 …”

Section: Compoundmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Control of the Cholesteric Pitch by Some Azo Photochemical Chiral Switches

Pieraccini

Gottarelli

Labruto

et al. 2004

Chemistry A European J

115

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“…A unique approach to unidirectional rotors has been taken by Feringa and coworkers. Based on overcrowded helical systems they designed rotors that depend on photophysical cis-trans isomerization followed by thermally induced helix inversion [225,226]. The designed handedness of the rotor determined the sense of rotation.…”

Section: Diastereomers and Diastereomeric Recognitionmentioning

confidence: 99%

Molecular chirality at surfaces

Ernst

2012

Physica Status Solidi (b)

219

264

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With the adsorption of larger molecules being increasingly tackled by surface scientists, the aspect of chirality often plays a role. This paper gives a topical review of molecular chirality at surfaces and gives a phenomenological overview of different aspects of adsorption and self‐assembly of chiral and prochiral molecules and the principles of mirror‐symmetry breaking at a surface. After a brief introduction into the history of molecular chirality and the important role it played for understanding the spatial structure of molecules, definitions of chirality are presented. Topics treated here are principle ways to create single chiral adsorbates, chiral ensembles, and monolayers by achiral molecules, adsorption of intrinsically chiral molecules at achiral and chiral surfaces, long‐range symmetry breaking in two‐dimensional (2D) crystals due to additional chiral bias, chiral restructuring of solid surfaces under the influence of chiral molecules, switching the handedness of adsorbates, and chirality at the liquid/air interface. An outlook onto further potential research directions and recommendations for further reading, including nonsurface‐related sources of chiral topics completes this paper.

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“…Compounds that interconvert between different isomers having unique absorption spectra when stimulated with light are referred to as photochromic and the process is called photochromism. In these systems, the changes in the electronic patterns responsible for the changes in colour also result in variations in other practical physical properties such as luminescence, [3][4][5][6][7] electronic conductance, [8,9] refractive index, [10][11][12][13] optical rotation, [14][15][16] and viscosity. [17,18] The photomodulation of these properties has the potential to significantly advance optoelectronic technologies such as waveguides, [19,20] read/write/erase optical information storage systems, [21] and actuators.…”

mentioning

confidence: 99%

High‐Content Photochromic Polymers Based on Dithienylethenes

2005

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Dithienylethenes (DTEs) are one of the most promising classes of photochromic compounds for use in optoelectronic devices such as waveguides, memory media and sensors. The development of DTE based polymers that contain a high mass-content of the photoactive DTE component, that maintain their photochromic activity in the solid-state and that are easily processed into thin-films under a variety of conditions is critical for the implementation of the materials into useful applications. This Microreview provides an overview of the

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Chiroptical Molecular Switches

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Cited by 95 publications

References 0 publications

The Control of the Cholesteric Pitch by Some Azo Photochemical Chiral Switches

The Control of the Cholesteric Pitch by Some Azo Photochemical Chiral Switches

Molecular chirality at surfaces

High‐Content Photochromic Polymers Based on Dithienylethenes

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