Hindrance of photodimerization of coumarin derivative induced by pillar[5]arene-based molecular recognition in water

Abstract

An easy and simple method for the impediment of the photodimerization of coumarin derivative induced by pillar[5]arene-based molecular recognition was provided. Moreover, we successfully use this system in supra-amphiphile self-assembly in water.

Supramolecular Valves Functionalized Rattle-Structured UCNPs@hm-SiO2 Nanoparticles with Controlled Drug Release Triggered by Quintuple Stimuli and Dual-Modality Imaging Functions: A Potential Theranostic Nanomedicine

“…Prior to acid/alkali stimuli-responsive release experiments, we first studied the pH-driven movement behavior of WP[5] along molecular stalks, Cys-Nba, containing two recognizable motifs by 1 H NMR spectroscopy (Figure a). On the basis of the previous literature, WP[5] macrocycles cannot form stable supramolecular complexes with coumarin derivatives because of very weak binding affinity . The addition of 1.0 equiv of WP[5] to the neutral solution of Cys-Nba resulted in peak broadening and significant upfield shifts of the proton signals on Cys motif, including H h’ (Δδ h’ = −0.62 ppm), H i’ (Δδ i’ = −0.59 ppm), H j’ (Δδ j’ = −0.59 ppm), and H k’ (Δδ k’ = −0.59 ppm), while the resonance signals for WP[5] protons shifted downfield (Figure a­(2),(3)).…”

“…On the basis of the previous literature, WP [5] macrocycles cannot form stable supramolecular complexes with coumarin derivatives because of very weak binding affinity. 44 The addition of 1.0 equiv of WP [5] to the neutral solution of Cys-Nba resulted in peak broadening and significant upfield shifts of the proton signals on Cys motif, including H h' (Δδ h' = −0.62 ppm), H i' (Δδ i' = −0.59 ppm), H j' (Δδ j' = −0.59 ppm), and H k' (Δδ k' = −0.59 ppm), while the resonance signals for WP [5] protons shifted downfield (Figure 5a(2),(3)). At this moment, the protons of the Nba motif remain unchanged compared with the uncomplexed state.…”

Responsive pillar[n]arene materials

“…[98] In addition to isomerization, photoinduced bond cleavage [99,100] and dimerization have also been applied to photoresponsive morphology change. [101] Temperature is also a clean stimulus, and it directly affects the solubility and hydrophilicity of the building blocks.…”

“…A similar concept is also involved in photoisomerization of spiropyran, where the photoinduced hydrophilicity change contributes to the morphology change [98] . In addition to isomerization, photoinduced bond cleavage [99,100] and dimerization have also been applied to photoresponsive morphology change [101] …”