Reversible Photomorphism in Surface Monolayers

Karthaus, Olaf; Shimomura, Masatsugu; Hioki, M.; R, Tahara; Nakamura, Hiroshi

doi:10.1021/ja9614272

Cited by 53 publications

(48 citation statements)

References 23 publications

(22 reference statements)

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“…This is different from the observation for the Gemini surfactant with diamino-stilbene disulfonate as the spacer (which is denoted as amphiphile 1 in Ref. 20), in which the cis-A E was remarkably smaller than the trans-A e . 20 In that case, the ionized (sulfonated) spacer was a determining factor leading to a "V"-configuration of the spacer at the air/water interface, which is schematically shown in Figure 4 as suggested by Karthaus and Shimomura.…”

Section: Photoisomerization Of the Azobenzene Spacercontrasting

confidence: 88%

“…20), in which the cis-A E was remarkably smaller than the trans-A e . 20 In that case, the ionized (sulfonated) spacer was a determining factor leading to a "V"-configuration of the spacer at the air/water interface, which is schematically shown in Figure 4 as suggested by Karthaus and Shimomura. 20 Contrarily, the azobenzene spacer of MC m (azo)MC m is electroneutral and therefore, their cis-isomers perhaps adopt another configuration similar to planar structure as calculated by CPK molecular models (Figure 3, right), whose cross-sectional area is 0.91 nm 2 per molecule which is very close to the measured cis-A e .…”

Section: Photoisomerization Of the Azobenzene Spacermentioning

confidence: 95%

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Orientation of the Azobenzene Spacer of Carboxylic Methyl Ester Gemini Surfactants in Langmuir Monolayer

Song¹,

Zhao²

2010

Chin. J. Chem.

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The Langmuir monolayer of carboxylic methyl ester Gemini surfactants with the azobenzene spacer, referred to as MC m (azo)MC m , was prepared and the π-A isotherms were measured. The result revealed an orientational picture of the azobenzene spacer at the air/water interface. Before irradiation, the planar trans-azobenzene group adopted an approximate configuration parallel to the interface and lay on the air/water interface. After UV-light irradiation, the spacer became the twisted cis-one. Because of the location of the polar headgroups at the air/water interface, the two phenyl rings were also forced to take a near-parallel orientation with the interface to reduce the free energy. As a result, the spacer thin-layer was "thickened", which caused an elevation in collapse pressure.

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Section: Photoisomerization Of the Azobenzene Spacercontrasting

confidence: 88%

Section: Photoisomerization Of the Azobenzene Spacermentioning

confidence: 95%

Orientation of the Azobenzene Spacer of Carboxylic Methyl Ester Gemini Surfactants in Langmuir Monolayer

Song¹,

Zhao²

2010

Chin. J. Chem.

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“…Another promising direction for exploring how light can be used to control material properties is light-switchable surfactants. [58][59][60][61] They accumulate at fluid interfaces. By switching locally between the two isomeric states, the surface tension changes and its gradient drives Marangoni flow.…”

Section: Discussionmentioning

confidence: 99%

Kinetic Monte Carlo simulations for birefringence relaxation of photo-switchable molecules on a surface

Tavarone

Stark

2016

The Journal of Chemical Physics

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Recent experiments have demonstrated that in a dense monolayer of photo-switchable dye methyl-red molecules the relaxation of an initial birefringence follows a power-law decay, typical for glass-like dynamics. The slow relaxation can efficiently be controlled and accelerated by illuminating the monolayer with circularly polarized light, which induces trans-cis isomerization cycles. To elucidate the microscopic mechanism, we develop a two-dimensional molecular model in which the trans and cis isomers are represented by straight and bent needles, respectively. As in the experimental system, the needles are allowed to rotate and to form overlaps but they cannot translate. The out-ofequilibrium rotational dynamics of the needles is generated using kinetic Monte Carlo simulations. We demonstrate that, in a regime of high density and low temperature, the power-law relaxation can be traced to the formation of spatio-temporal correlations in the rotational dynamics, i.e., dynamic heterogeneity. We also show that the nearly isotropic cis isomers can prevent dynamic heterogeneity from forming in the monolayer and that the relaxation then becomes exponential. C 2016 AIP Publishing LLC. [http://dx

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“…Furthermore, it features a photoswitchable stilbene double bond. [11] The Cu I -catalyzed cycloaddition with alkynes such as 3 a or 3 b smoothly yielded rodlike molecules 4 a and 4 b as their tetrabutylammonium salts (Scheme 1 a). [12] Indeed, stepwise addition of 4 a to a solution of cage 1 a in CD 3 CN resulted in immediate and quantitative uptake of the rodlike molecule inside the metal-organic cage molecule in the fashion of a pseudorotaxane (Figure 1 a).…”

mentioning

confidence: 99%

“…[14] Furthermore, free guest 4 a (a 18 mm solution in CHCl 3 /CH 3 CN (1:1), N 2 purged) can be isomerized into its cis isomer by irradiation at 365 nm within 10 s, whereas encapsulated 4 a is protected from the photoisomerization within the cage 1 a (see the Supporting Information). [11] Surprisingly, the uptake of 4 a into 1 a was finished within seconds, and therefore, in light of considerably slow ligand exchange with Pd II ions, this occurs too quickly for a mechanism that involves the decomplexation of the ligands from the Pd II centers of the cage. Furthermore, repeating the uptake experiment with the corresponding Pt II cage 1 b, which is expected to have a structure similar to that of cage 1 a, indicated a similar quick encapsulation despite the fact that the ligand exchange in Pt II complexes is known to be much slower than in Pd II complexes (see the Supporting Information).…”

mentioning

confidence: 99%