Aqueous assembly of a (pseudo)rotaxane with a donor–π–acceptor axis formed by a Knoevenagel condensation

Jucker, Laurent; Aeschi, Yves; Mayor, Marcel

doi:10.1039/d1qo00643f

Cited by 2 publications

(8 citation statements)

References 56 publications

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“…Intriguingly, we had previously confirmed that the bulk of the triazol-propylsulfonate groups on the chromophore suffice to mechanically interlock a rotaxane. 26 We anticipated 6 to be of similar size but probably underestimated the role of the ionic subunits in the mechanical fixation in solution. However, it appears that the macrocycle can pass the stopper subunit of 6 already at room temperature.…”

Section: Resultsmentioning

confidence: 97%

“…22,23 Stoppers at the ends of the rod mechanically interlock the dicationic macrocycle M. We chose the Diederich-type cyclophane M 24,25 due to its permanently charged piperidinium groups, the high association constants it exhibits in water, its ability to change emission properties of guests, as well as the ease of analysis by NMR due to its high symmetry and significant changes in chemical shifts upon complexation. [26][27][28][29][30] As additional water solubilizing groups anionic sulfonates were considered, pulling the rod towards the cathode and thereby supporting an upright arrangement of the rotaxane immobilized on the anode.…”

Section: Resultsmentioning

confidence: 99%

“…Our previously synthesized [2]rotaxane based on chromophore 7 showed increased quantum yields upon encapsulation in both water and DMSO, making it another potential candidate for our endeavor. 26 As a result of the less electron-withdrawing substituent, its absorption and emission are hypsochromically shifted compared to derivatives of 3. Its optical properties are thus closer to the gold interband absorption, which might increase the challenges faced in the intended experiment.…”

Section: Resultsmentioning

confidence: 99%

“…25 Chromophore 7 was previously described by our group. 26 Fabrication of the gold nano-antenna is briefly described in the supporting information.…”

Section: Methodsmentioning

confidence: 99%

“…We have previously observed similar fluorescence enhancements with mechanically interlocked structures bearing the same chromophore core. 26 These changes in intensity are crucial to observe the electrostatic field induced switching in an optical antenna gap.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

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Development of Rotaxanes as E-Field-Sensitive Superstructures in Plasmonic Nano-Antennas

et al. 2022

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We present the concept of electrostatic field driven supramolecular translation within electrically connected plasmonic nano-antennas. The antenna serves as anchoring point for the mechanically interlocked molecules, as electrode for the electrostatic field, and as amplifier of the antenna-enhanced fluorescence. The synthesis of a push-pull donor-π-acceptor chromophore with optical properties aligned to the antenna resonance is described and its immobilization on the surface demonstrated. Photoluminescence experiments of the chromophore on a gold nanoantenna are shown, highlighting the molecule-antenna coupling and resulting emission intensity increase. The successful synthesis of an electrostatic field sensitive [2]rotaxane in water is described and the tightrope walk between functionality and water solubility is illustrated by unsuccessful designs. In solution, enhanced fluorescence quantum yield is observed for the chromophore comprised in the mechanically interlocked [2]rotaxane in water and DMSO compared to the reference rod, ideal for future experiments in plasmonic nano-antennas.

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

“…25 Chromophore 7 was previously described by our group. 26 Fabrication of the gold nano-antenna is briefly described in the supporting information.…”

Section: Methodsmentioning

confidence: 99%

Section: Accepted Manuscriptmentioning

confidence: 99%

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Development of Rotaxanes as E-Field-Sensitive Superstructures in Plasmonic Nano-Antennas

et al. 2022

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Post-synthetic modification of near-infrared absorbing cyclodextrin-encapsulated cyanine dyes for controlling absorption wavelength, stability, and singlet oxygen generation

Zhang,

Masui,

Masai

et al. 2024

Bulletin of the Chemical Society of Japan

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In this study, near-infrared absorbing rotaxane-type cyanine dyes exhibit high tolerance to various chemical reactions, which is attributed to the encapsulation effect of their cyclic molecules. As a result, rotaxane dyes can be post-modified on the host α-cyclodextrin or guest cyanine skeleton to adjust their solubility, absorption wavelength, stability, and singlet oxygen generation ability. The guest modification product obtained via the Heck reaction demonstrates a red shift of its absorption wavelength owing to the extended conjugation system. Moreover, the products of host modification through the methylation and benzylation of all cyclodextrin hydroxyl groups not only become lipophilic and show extended absorption, but also exhibit higher photooxidation tolerance, lower singlet oxygen generation rate, and increased singlet oxygen tolerance, indicating their potential applicability as highly durable dyes. Furthermore, the outstanding singlet oxygen tolerance of these dyes enables their use in long-life singlet oxygen generators, in which the total amount of singlet oxygen increases. This work demonstrates that an intrinsically unstable near-infrared cyanine dye can be used as a synthetic intermediate by stabilizing it via α-cyclodextrin encapsulation, allowing the post-modification of various properties of cyanine dyes toward the higher-order near-infrared-absorbing materials with complex functionalities and diverse utilities.

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Aqueous assembly of a (pseudo)rotaxane with a donor–π–acceptor axis formed by a Knoevenagel condensation

Abstract: The incorporation of a linear D-π-A “push-pull” chromophore synthesized by a Knoevenagel condensation as axle of a rotaxane is reported. While the introduction of the mechanical stoppers by the reversible...

Cited by 2 publications

References 56 publications

Development of Rotaxanes as E-Field-Sensitive Superstructures in Plasmonic Nano-Antennas

Development of Rotaxanes as E-Field-Sensitive Superstructures in Plasmonic Nano-Antennas

Post-synthetic modification of near-infrared absorbing cyclodextrin-encapsulated cyanine dyes for controlling absorption wavelength, stability, and singlet oxygen generation

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