Supramolecular oligourethane gel as a highly selective fluorescent “on–off–on” sensor for ions

Abstract

An AIE-active oligourethane gel was designed and synthesized, and it was demonstrated that the gel is a highly-selective and reversible sensor for Fe3+, HSO4− and F− ions.

A stimuli-responsive pillar[5]arene-based hybrid material with enhanced tunable multicolor luminescence and ion-sensing ability

“…By immobilizing L1 and pyridine-modified conjugated pillar[5]arene (L2) to the Cd (II) metal cores via coordination, we successfully obtained an interesting luminescent material which possessed strong emission both in suspensions and solid states and displayed fascinating tunable multicolor luminescence in response to various stimulating factors, including solvents, ions and acid. In particular, the luminescent responses toward Fe 3+ showed high selectivity and sensitivity, suggesting the great potential of this new material for application in fluorescent sensing [ 34 , 35 ]. The color-tuning responses toward various stimuli have been rationally attributed to the altered electronic distributions among the ligands through spectral analysis and theoretical calculations.…”

Progress in aggregation‐induced emission‐active fluorescent polymeric hydrogels

“…For example, Feng and coworkers designed and synthesized an AIE‐active oligourethane gelator that could self‐assemble into supramolecular hydrogel system through the combination of hydrogen‐bonding, π–π stacking, and van der Waals interactions (Figure 12A). [ 57 ] Owing to the weak and dynamic nature of these supramolecular interactions, the fluorescence intensity of the self‐assembled system could be selectively adjusted by Fe 3+ , HSO 4 − , and F − , indicating its capacity for real‐time detection of these ions (Figure 12B,C). Very recently, Sun et al.…”

“…(C) Photos showing the fluorescence response of the FPH for various metal ions and anions. Reproduced with permission: 2020, The Royal Society of Chemistry [ 57 ]…”

“…For example, Feng and coworkers designed and synthesized an AIE-active oligourethane gelator that could self-assemble into supramolecular hydrogel system through the combination of hydrogen-bonding, π-π stacking, and van der Waals interactions (Figure 12A). [57] Owing to the weak and dynamic nature of these supramolecular interactions, the fluorescence intensity of the self-assembled system could be selectively adjusted by Fe 3+ , HSO 4 − , and F − , indicating its capacity for real-time detection of these ions (Figure 12B,C). Very recently, Sun et al also took advantage of hydrogenbonding, π-π stacking, and van der Waals interactions to present another AIE-active supramolecular hydrogel example with acid/base-triggered transparency/fluorescence response, and further demonstrated its potential use for smart window and secret display materials.…”

Supramolecular oligourethane gels as light-harvesting antennae: achieving multicolour luminescence and white-light emission through FRET

“…Our previous work has exploited the versatility of urethane linkages to introduce different kinds of components into OU backbones to provide richer H-bonding sites to drive the construction of gel materials with some novel optical properties, like ion sensors or mechanically-sensitive multicolour luminescent gels. [39][40][41] Polyurethane has been claimed as the world's ''sixth largest resin-based polymer group'' 42 which can be regarded as an important milestone in modern technology. In recent years, oligo/polyurethanes have been designed and investigated in optical fields largely due to their advantages over many competitor materials, like large-scale production, good mechanical toughness and abrasion resistance.…”