Photoresponsive host–guest chemistry and  relaxation time of fluorinated cyclodextrin and arylazopyrazole-functionalized DOTA metal complexes

Simke, Julian; Böckermann, Till; Bergander, Klaus; Klabunde, Sina; Ravoo, Bart Jan

doi:10.1039/d0ob02482a

Cited by 12 publications

(15 citation statements)

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“…13−16 Similar to azobenzenes, 9,12,17−19 AAPs can change their E/Z configuration by photoisomerization using 520 nm visible or 365 nm UV light, 20−22 but are considered as superior analogues to azobenzene derivatives because of their high photostationary states of >90% for switching in both directions and their remarkably long thermal half-life times. 18,23,24 Depending on the system under investigation, the lightinduced changes of the contact angle Θ vary to a large extent. For instance, Kwon et al 25 showed for dye-sensitized TiO 2 surfaces that Θ was changed reversibly by ∼40°when the samples were irradiated with light.…”

Section: ■ Introductionmentioning

confidence: 99%

Dynamic Wetting of Photoresponsive Arylazopyrazole Monolayers is Controlled by the Molecular Kinetics of the Monolayer

et al. 2022

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Smart surfaces that can change their wettability on demand are interesting for applications such as self-cleaning surfaces or lab-on-a-chip devices. We have synthesized arylazopyrazole (AAP) phosphonic acids as a new class of photoswitchable molecules for functionalization of aluminum oxide surfaces. AAP monolayers were deposited on α-Al2O3(0001) and showed reversible E/Z photoswitching that can trigger contact angle changes of up to ∼10°. We monitored these changes on the macroscopic level by recording the contact angle while the monolayer was switched in situ. On the molecular level, time-dependent vibrational sum-frequency generation (SFG) spectroscopy provided information on the kinetic changes within the AAP monolayer and the characteristic times for E/Z switching. In addition, vibrational SFG at different relative humidity indicates that the thermal stability of the Z configuration is largely influenced by the presence of water which can stabilize the Z state and hinder E → Z switching of the AAP monolayer when it is wetted with H2O. Having established the switching times on the molecular scale, we additionally measured the dynamic contact angle and show that the time scales of the substrate and droplet dynamics can be extracted individually. For that, we report on a relaxation model that is solved analytically and is verified via a comparison with simulations of a Lennard–Jones system and with experimental data. The slower E to Z switching in the presence of the droplet as compared to the vapor phase is rationalized in terms of specific interactions of water with the exposed AAP moieties.

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Section: ■ Introductionmentioning

confidence: 99%

Dynamic Wetting of Photoresponsive Arylazopyrazole Monolayers is Controlled by the Molecular Kinetics of the Monolayer

et al. 2022

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“…Furthermore, the size and polarity of AAPs and the fact that many drugs indeed contain pyrazole derivatives play important roles in expanding the applicability of these photoswitches in photopharmacology . On the basis of the high potential of AAPs for application in biological systems, numerous reports, in particular, by Fuchter, ,, Ravoo, ,, and Venkataramani, , have been published in recent years . Although this enabled novel AAP derivatives with promising photophysical and photochemical properties, the E → Z isomerization was induced with UV light in all of these AAPs.…”

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confidence: 99%

Photoswitching of ortho-Aminated Arylazopyrazoles with Red Light

2021

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Bidirectional photoswitching of arylazopyrazoles with visible light is enabled by substitution with pyrrolidine and piperidine in the ortho-position of the phenyl ring. The absorption maxima were red-shifted and the molar absorption coefficients in the visible range increased significantly, allowing the use of blue light (λ = 465 nm) for the E → Z isomerization and red light (λ = 600 nm) for the Z → E isomerization. N-Methylation of the pyrazole leads to an excellent thermal stability of the Z isomer.

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“…In fact, CDs decorated with multiple Gd ions provoke a short relaxation time. In this sense, the authors reported the synthesis of fluorinated CD (FCD), which can modulate the relaxation time of 19 F, longitudinal (T 1 ) and transversal (T* 2 ) by the light-responsive host-guest complexation with arylazopyrazole (AAP)-functionalized 1,4,7,10-tetraazacyclodo-decane-1,4,7,10-tetraacetic acid (DOTA) metal complexes (Scheme 5) [86]. FCD is a highly soluble compound that contains 21 equivalent fluorine atoms, making it a suitable contrast agent for MRI.…”

Section: Miscellaneousmentioning

confidence: 99%

“…Representation of the photoresponsive modulation of T 1 /T* 2 relaxation time of FCD and AAP-functionalized DOTA metal complexes by host-guest interaction. Reproduced with permission from[86], RSC, 2021.…”

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confidence: 99%

Relevance of Fluorinated Ligands to the Design of Metallodrugs for Their Potential Use in Cancer Treatment

et al. 2022

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Fluorination of pharmaceutical agents has afforded crucial modifications to their pharmacological profiles, leading to important advances in medicinal chemistry. On the other hand, metallodrugs are considered to be valuable candidates in the treatment of several diseases, albeit with the caveat that they may exhibit pharmacological disadvantages, such as poor water solubility, low bioavailability and short circulating time. To surmount these limitations, two approaches have been developed: one based on the design of novel metallodrug-delivering carriers and the other based on optimizing the structure of the ligands bound to the metal center. In this context, fluorination of the ligands may bring beneficial changes (physicochemical and biological) that can help to elude the aforementioned drawbacks. Thus, in this review, we discuss the use of fluorinated ligands in the design of metallodrugs that may exhibit potential anticancer activity.

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Photoresponsive host–guest chemistry and relaxation time of fluorinated cyclodextrin and arylazopyrazole-functionalized DOTA metal complexes

Abstract: Light-responsive modulation of the longitudinal (T1) and transversal (T2*) relaxation times of a fluorinated cyclodextrin has been achieved by host guest complexation with arylazopyrazole-modified metal complexes in aqueous solution. This...

Cited by 12 publications

References 50 publications

Dynamic Wetting of Photoresponsive Arylazopyrazole Monolayers is Controlled by the Molecular Kinetics of the Monolayer

Dynamic Wetting of Photoresponsive Arylazopyrazole Monolayers is Controlled by the Molecular Kinetics of the Monolayer

Photoswitching of ortho-Aminated Arylazopyrazoles with Red Light

Relevance of Fluorinated Ligands to the Design of Metallodrugs for Their Potential Use in Cancer Treatment

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