Coexistence of 1 : 1 and 2 : 1 inclusion complexes of indigo carmine

Yanshyna, Oksana O.; Avram, Liat; Shimon, Linda J. W.; Klajn, Rafał

doi:10.1039/d1cc07081a

Cited by 7 publications

(5 citation statements)

References 34 publications

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“…2e , f). This linear relationship suggests i) a high affinity of 2 to cage 1 and ii) a strongly cooperative binding of 2 to 1 , with the 2:1 complex-forming preferentially 42 to a putative 1:1 complex 43 (even in the presence of an excess of the guest; note that for a 1:1 complex, fluorescence should be preserved, at least partially 26 , 31 , 43 – 45 ).…”

Section: Resultsmentioning

confidence: 99%

Encapsulation within a coordination cage modulates the reactivity of redox-active dyes

et al. 2022

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Confining molecules within well-defined nanosized spaces can profoundly alter their physicochemical characteristics. For example, the controlled aggregation of chromophores into discrete oligomers has been shown to tune their optical properties whereas encapsulation of reactive species within molecular hosts can increase their stability. The resazurin/resorufin pair has been widely used for detecting redox processes in biological settings; yet, how tight confinement affects the properties of these two dyes remains to be explored. Here, we show that a flexible PdII6L4 coordination cage can efficiently encapsulate both resorufin and resazurin in the form of dimers, dramatically modulating their optical properties. Furthermore, binding within the cage significantly decreases the reduction rate of resazurin to resorufin, and the rate of the subsequent reduction of resorufin to dihydroresorufin. During our studies, we also found that upon dilution, the PdII6L4 cage disassembles to afford PdII2L2 species, which lacks the ability to form inclusion complexes – a process that can be reversed upon the addition of the strongly binding resorufin/resazurin guests. We expect that the herein disclosed ability of a water-soluble cage to reversibly modulate the optical and chemical properties of a molecular redox probe will expand the versatility of synthetic fluorescent probes in biologically relevant environments.

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Section: Resultsmentioning

confidence: 99%

Encapsulation within a coordination cage modulates the reactivity of redox-active dyes

et al. 2022

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“…We applied isothermal titration calorimetry (ITC) to quantify the binding energy of E-POS to H (Ka = 2.06•10 4 M -1 , in a 1:1 binding model, see SI Chapter 5 for details), which, due to its positive charge, was found to be significantly lower than for previously reported guests. 54,55 The binding process is still driven by enthalpy, as the encapsulation of the surfactants into H's cavity is an exothermic process (ΔH = −22.64 kJmol -1 ) that is connected with a decrease in disorder (ΔS = −4.91 Jmol -1 K -1 ).…”

Section: Surfactant Encapsulationmentioning

confidence: 99%

Surface Tension Manipulation with Visible Light through Sensitized Disequilibration of Photoswitchable Amphiphiles

Gemen,

Stövesand,

Glorius

et al. 2024

Preprint

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The light-induced N=N double bond isomerization of azoarenes lies at the heart of numerous applications ranging from catalysis, energy storage, or drug release to optogenetics and photopharmacology. While efficient switching between their E and Z states has predominantly relied on direct UV light excitation, a recent study by Klajn and co-workers introduced visible light sensitization of E azoarenes and subsequent isomerization as a tool coined disequilibration by sensitization under confinement (DESC) to obtain high yields of the out-of-equilibrium Z isomer. This host-guest approach is, however, still constrained to small, minimally substituted azoarenes with limited applicability and functionality in advanced multicomponent molecular systems. Herein, we expand the DESC concept to steer the supramolecular assembly of surfactants at the air-water interface. Leveraging our expertise with photoswitchable arylazopyrazole amphiphiles, we induce substantial alterations of the surface tension and surface excess of water through their reversible E-Z isomerization. After studying the binding of positively and negatively charged surfactants to the host, we find that the extent of surface activity differences upon visible light irradiation for both isomer states is comparable to those observed for direct UV light excitation. The method is demonstrated on a large range of concentrations (from µM to mM) and can be equally activated using green or red light, depending on the sensitizer chosen. The straightforward implementation of visible light photoswitch sensitization in a complex molecular network showcases how DESC enables the improvement of existing light-responsive systems and allows for the development of novel applications driven exclusively with visible light.

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“…14,23,38 However, C offers two additional advantages: first, it contains two large windows, which makes the hydrophobic cavity readily accessible; second, the cage is flexible (owing to the rotation around the C-N bonds connecting the imidazole groups to the panel's central benzene ring 39 ) and can adopt a variety of conformations. This structural flexibility has enabled encapsulation of a variety of structurally diverse guests 23,[39][40][41][42] and efficient photoisomerization reactions of the encapsulated molecules, even when accompanied by large structural changes. 43,44 As a proof-of-concept, we worked with combinations of (1) aromatic compounds a1-a4 (Scheme 1B), which we collectively refer to as polycyclic aromatic hydrocarbons (PAHs; native or substituted), and (2) BODIPY dyes b1-b4 (Scheme 1C).…”

Section: The Bigger Picturementioning

confidence: 99%

Ternary host-guest complexes with rapid exchange kinetics and photoswitchable fluorescence

Gemen

Białek

Kazes

et al. 2022

Chem

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Coexistence of 1 : 1 and 2 : 1 inclusion complexes of indigo carmine

Abstract: We show that the optical properties of indigo carmine can be modulated by encapsulation within a coordination cage.

Cited by 7 publications

References 34 publications

Encapsulation within a coordination cage modulates the reactivity of redox-active dyes

Encapsulation within a coordination cage modulates the reactivity of redox-active dyes

Surface Tension Manipulation with Visible Light through Sensitized Disequilibration of Photoswitchable Amphiphiles

Ternary host-guest complexes with rapid exchange kinetics and photoswitchable fluorescence

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