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Recent advancements in ultra-sensitive detection, particularly the Aggregation Induced Emission (AIE) materials, have demonstrated a promising detection method due to their low cost, real-time detection, and simplicity of operation.

In this review, we provide a comprehensive review article that emphatically compares and summarizes the dependency relationship between various chemical designs and application performance based on SGs derived from pillar[5]arene.

A feasible strategy has been developed by using supramolecular host–guest interaction to regulate the ionic recognize properties of guest molecules.

Pillar[5]arene-based charge transfer dyes show bright circularly polarized luminescence. The intramolecular charge transfer from pillar[5]arene to triarylborane induces an approximately 10-fold increase in luminescence dissymmetry factors.

The detection of l-aspartic acid and l-glutamic acid was tackled using fluorescent microparticles constructed by the combination of aggregation-induced emission and self-assembly-induced Förster resonance energy transfer.

We synthesized and developed 1,3-dihydro-2H-imidazo[4,5-b]phenazine-2-thione as a ratiometric chemosensor for Hg2+ recognition in a DMSO/H2O (v/v = 9:1) binary solution. We rationally introduced the phenazine imidazole group as the fluorophore and the thione moiety as the recognition site to bind Hg2+. Interestingly, the chemosensor showed an ultrasensitive response to Hg2+, and the lowest limit of detection was 0.167 nM. In addition, it can also separate Hg2+ from aqueous solutions with excellent ingestion capacity, with an adsorption ratio of up to 96%. Furthermore, ion test strips based on chemosensors were fabricated for convenient and efficient detection of Hg2+.

Selective monitoring and targeted identification of various noxious ions have received significant attention in biology, industry and environments. Herein, we developed an easily available colorimetric and fluorescence sensor (PZ) based on phenazine derivative, successfully achieving the discriminative detection of Hg2+ and CN− ions. Compared with other interfering ions, PZ had high sensitivity and specificity towards Hg2+ and CN−. The lowest limits of Hg2+ and CN- by PZ were 1.52 × 10−8 M and 7.05 × 10−7 M, respectively. Significantly, this chemosensor PZ allowed visual monitoring of toxic Hg2+ and CN− ions in a few seconds, presenting a great potential in the practical application (skin-whitening cosmetic, water samples, and nutlet). Such an effective strategy is expected to offer some guidance for distinguishing the identification of toxic ions in optical sensing.

Regulation of a conjugate rigid plane structure based on bisbenzimidazole derivatives to research the structure-effective relationship between conjugate systems size and fluorescence sensing properties.

Anion recognition has continuously attracted significant attention due to its important role in environmental and biological sciences. Here, we have designed and synthesized an electron-deficient fluorinated leaning pillar[6]arene 1 that contains two tetrafluoro-benzene units. The electron-deficient fluorinated leaning pillar[6]arene 1 is capable of selectively recognizing iodide anions to form a host-guest complex with 1 : 1 stoichiometry driven by anion-π interactions. Our work ascribes this selective recognition to the preorganization of macrocycles, suitable cavity size, and the effect of anion-π interactions. The innovative application of this macrocycle offers us a new avenue for the design of selective receptors for anions and electron-deficient macrocyclic arenes.

We developed fluorescence sensor for detecting HCHO. Such molecular sensors have great potential to be utilized. We hope that this simple fluorescent probe can arouse widespread attention in the fields of molecular sensing and food chemistry.

This review comprehensively summarized and discussed the recent achievements towards innovative strategies, excellent properties and promising application to create functional materials based on phenazine derivatives in optical sensing and electrochemistry.

Metallogel-based six membered sensor arrays show applications in multi-analyte detection and fluorescence encryption.

The early detection of volatile organic compounds (VOCs) is crucial for sustainable development. Improving the binding properties of crystalline materials for special VOC guests is a tough challeng...

In practical applications, fixing a fluorescent sensor on a solid composite film matrix can settle the boundaries of keeping the sensor in the solution state. Herein, we first presented a preparation of anime-response membrane by utilizing the edible gelatin as a film-forming skeleton to immobilize the dual phenazine derivative (PD-6), acting as amine-responsive functional units to fabricate a novel solid sensor. In order to ensure the sensor (PD-6 film) is available in the actual application, the mechanical properties, anime-responsive performance, and further application for monitoring shrimp freshness were fully characterized. Those observations indicated that the PD-6 film not only enhanced the sensitivity to anime, but also strengthened the application potential as a solid fluorescent sensor with flexible recyclability and favorable antibacterial properties. It is hoped that this valuable strategy could open a new avenue to overcome the application limitations of the sensor in the solution state.

Herein, a novel pillar[5]arene-based gemini-[1]rotaxane molecule DEP5 was successfully designed and synthesized. Interestingly, the gemini-[1]rotaxane DEP5 serving as a chemosensor could selectively recognize L-Arg with high sensitivity and its lowest detection limit (LOD) was 1.43 × 10−7 M. Simultaneously, the gemini-[1]rotaxane DEP5 could assemble into the microsphere structure and its microsphere morphology could transform into cross-linked supramolecular networks through host–guest interactions with L-Arg. Furthermore, its microsphere morphology could be recovered again by the addition of competitive reagent guest trifluoroacetic acid (TFA). Therefore, this work provides a new and simple approach to construct gemini-[1]rotaxane-based smart materials which could assemble into the microsphere in solution and achieve reversible regulation of morphology between the microsphere and cross-linked supramolecular networks by external chemical stimuli (L-Arg/TFA). This kind of material not only has a perspective in L-Arg sensors but also has potential for application in other fields such as drug control release.

A novel photochemical sensor (FQ-5) based on quinoline-functionalized phenazine derivatives was designed and synthesized. The FQ-5 showed a good response to certain pH values in a wide pH range (from 2.0 to 13.0). Particularly, at pH = 12 and 13, the fluorescence emission showed obvious enhancement, the fluorescence quantum yields could reach 80.9% and 77.0%, respectively, and the color of solution changed from yellow to purple. Meanwhile, the sensor not only showed a rapid response toward CO2, but also showed high selectivity and sensitivity for the detection of L-Arg in buffer solution (pH = 7), and the limit of detection (LOD) was 8.1 × 10−8. Furthermore, the FQ-5-based fluorescent writing material and CO2 gas reaction device were developed for the rapid detection of L-Arg and CO2. Therefore, this work will provide a new approach for photochemical sensing in the detection of multiple substrates.

We developed a novel strategy whereby Hg2+ induces a supramolecular polymer network to form fluorescent nanoparticles (NPs) in situ. This strategy was successfully applied in efficiently sensing Hg2+ in living cells and separating Hg2+ from water.

A simple and unique dual-channel chemical probe (DH) was designed and synthesized, which not only realized sequential recognition of Cu2+ and CN− by colorimetric and fluorometric methods, but also realized fluorescence detection of CN−. When different cations (Co2+, Mg2+, Ni2+, Cd2+, Hg2+, Al3+, Ag+, Cu2+, Pb2+, Fe3+, Zn2+ and Ca2+) were added into the solution containing the probe molecule DH, only Cu2+ induced an observable change in the UV-vis and fluorescence spectra, indicating that the probe molecule can be applied for specific recognition of Cu2+. The anti-interference experiment of DH to Cu2+ showed that DH has good selectivity for detecting Cu2+, with a detection limit of 7.05 × 10−7 M. In particular, the fluorescence “ON–OFF–ON” process can be recycled by sequentially adding Cu2+ and EDTA, and the fluorescence intensity remained unchanged after ten times. This observation suggested that DH can achieve reversible highly sensitive response to Cu2+ and EDTA, and can be used as a hypersensitive logic gate for Cu2+ detection. More interestingly, when different anions (CH3COO−, SO32−, H2PO4−, ClO4−, NO3−, HSO4−, I−, Cl−, F−, Br−, N3− and CN−) were added into the solution containing DH and Cu2+, only CN− induced color change of the solution from red to yellowish green, and the fluorescence intensity greatly enhanced, indicating that DH-Cu2+ has a specific response to CN−. The anti-interference experiment showed that DH-Cu2+ has good selectivity for CN−, with a detection limit of 8.11 × 10−6 M. Moreover, the probe molecule DH can detect CN−, with a detection limit of 7.61 × 10−6 M. Experimental and theoretical methods were applied to deeply study the detection mechanism of DH, present great potential in practical application for ion test strips and HeLa cell imaging reagents.

Developing novel stimuli-responsive fluorescent nanomaterials and achieving controllable regulation of the morphology and optical properties of this kind of material is very important. Herein, we demonstrate a novel way to construct stimuli-responsive fluorescent nanomaterials by rotaxanes. Significantly, a feasible method to reversibly control the morphology of nanomaterials from nanoparticles to nano-film has been developed. At the beginning of the work, a novel pillar[5]arene-based tri-[2]rotaxane was designed and synthesized. The tri-[2]rotaxane shows selective fluorescence response to suberic acid. Moreover, the tri-[2]rotaxane could self-assemble into fluorescent nanoparticles. By alternating addition of suberic acid and trimethylamine, the tri-[2]rotaxane-based nanomaterials could reversibly change from nanoparticles to nano-film, meanwhile, the fluorescence of the tri-[2]rotaxane shows “off–on–off” switch; this process is controlled by the formation and destruction of intermolecular hydrogen bonds. Reversible control of the morphology and optical properties of rotaxane-based nanomaterials have broad prospects in biomedicine and smart materials.

The exploration and understanding of self-assembly and stimuli-responsive mechanisms of supramolecular systems are of fundamental importance for researchers to plan syntheses reasonably. Herein, the self-assembly and ions responsive mechanisms of a tripodal quinolinamido-based supramolecular organogel (TBT-gel) were investigated through experiments and theoretical calculations including independent gradient model (IGM), localized orbitals locator (LOL) and hole-electron theory. According to these studies, the self-assembly mechanism of TBT-gel was based on strong threefold H-bonding and π-π interactions, which induced the TBT forming helical, one-dimensional supramolecular polymer. After addition of Fe3+ into the TBT-gel, the one-dimensional supramolecular polymer had been crosslinked by the Fe3+ through coordination interaction and formed a metallogel (TBT-Fe-gel). Interestingly, the TBT-gel showed selective fluorescent response for Fe3+ and F- based on a competitive coordination mechanism. Moreover, the study on fluorescence responsive mechanism of TBT-gel for Fe3+ and F- implied the ICT mode governs both the electron excitation and de-excitation processes. The calculated results were in agreement with the corresponding experimental results. Notably, the quantum chemical calculations provided a deep understanding and visualized presentation of the assembly and stimuli-responsive mechanisms.

Two novel supramolecular AIE polymer-based rare earth metallogels (PT-GEu and PT-GTb) were rationally designed and synthesized for the efficient detection and separation of cyanide (CN−) and perchlorate (ClO4−). PT-GEu and PT-GTb were prepared by introducing Eu3+ and Tb3+ into a novel supramolecular polymer (PT-G), which was constructed by the assembly of o-phthalimide functionalized pillar[5]arene host PM and tri-amide guest TH. The supramolecular polymer PT-G shows strong yellow aggregation-induced emission (AIE). Interestingly, after coordination with Eu3+ or Tb3+, the obtained AIE polymer-based rare earth metallogels (PT-GEu or PT-GTb) show “turn-off” AIE. Interestingly, PT-GEu and PT-GTb exhibit selective and sensitive fluorescent “turn-on” recognition for CN− and ClO4−, respectively. The lowest detection limits are 3.36 × 10−6 M for ClO4− by PT-GEu and 5.96 × 10−8 M for CN− by PT-GTb. In addition, the xerogel of PT-GEu and PT-GTb shows nice separation properties for ClO4− and CN−, the adsorption rate of these rare earth metallogels for ClO4− and CN− reached up to 92.86% and 93.33%. Moreover, ion detection test kits were prepared based on these rare earth metallogels, which rapidly detect CN− and ClO4−.

A fluorescent imidazophenazine-based derivative (S) has been successfully synthesised, and can be used as a chemsensor for relay recognition of CN– in DMSO/H2O (7 : 3, v/v) solution, which exhibited external stimuli-responsiveness. The sensor immediately responded with obvious colour changes (from red to purple) and fluorescent quenching when CN– was added to the S solution. Its detection limit for CN– is 2.16 × 10−7 M. In addition, NMR spectroscopy and density function theory calculations were also used to confirm the recognition mechanism. In particular, the fluorescence responding circle could be repeated three times by the sequential addition of CN– and CH3COO– or CN– and HSO4–. Moreover, a CN– detection test paper was prepared using S, providing a convenient method for CN– identification.

Multifunctional stimuli-responsive supramolecular polymers have applications in the field of smart materials. Herein, a tri-pillar[5]arene-based multifunctional stimuli-responsive supramolecular po...

Tryptophan (Trp) is very necessary for biosystems; therefore, high-efficient detection of Trp is an important subject. Hereof, based on our early research works on fluorescent sensors, we rationally designed and synthesized a fluorescent sensor (SNP5) based on N-(2-aminoethyl)-2-(hexylthio) acetamide-functionalized pillar[5]arene, which showed high selectivity and sensitive recognition for l-Trp (LOD = 2.19 × 10-8 M). Moreover, SNP5 exhibited aggregation-induced emission enhancement fluorescence. Within SNP5, the pillar[5]arene group could act as N-H···π- and C-H···π-interaction sites, as well as a H-bond-interaction site; meanwhile, the N-(2-aminoethyl)-2-(hexylthio) acetamide group also served as a multihydrogen-bonding site. As a result, SNP5 could selectively detect l-Trp through the synergy of the pillar[5]arene group and the N-(2-aminoethyl)-2-(hexylthio) acetamide group. Compared with previous work, the results of this work support the strategy that changing the functionalized group of the pillar[5]arene can adjust the selectivity of the pillar[5]arene-based sensor and achieve the detection of different amino acids. The detection mechanism was specifically researched through experiments and theoretical calculations including frontier orbitals, electrostatic potential, and the independent gradient model approach. Interestingly, these theoretical calculations not only supported the experimental results but also provided a visualized understanding of guest-adaptive multisupramolecular interactions between SNP5 and l-Trp.

The booming of host-guest assembly-based supramolecular chemistry provides abundant ways to construct functional systems and materials. Attracted by the important application prospect of white light emission and aggregation-induced emission (AIE) materials, herein, we report an efficient way for fabricating metal-free white light-emitting AIE materials through the supramolecular assembly of simple organic compounds: methoxyl pillar[5]arene (

In recent years, with the development of supramolecular chemistry, stimuli-responsive supramolecular gels have attracted more and more researchers’ interests. Among these gels, redox-responsive sup...

A catechol-functionalized phenazine imidazole (PD) was tailored with 2,3-diaminophenazine and 3,4-dihydroxy benzaldehyde, and it served as a hybrid acceptor for capturing HSO4− anions. The selectivity and sensitivity of the PD receptor for anion sensing were studied. It was found that the PD receptor could not only display a preferable sensitivity to HSO4− ions with a “turn–off” fluorescence response, but also have a strong anti-interference ability toward other common anions, especially basic anions such as CH3COO−, HPO42−, and H2PO4−. The anion recognition mechanism of PD towards HSO4− is based on multiple hydrogen bond interactions. Finally, the strips for anion detection were prepared, which were verified to be a convenient and high-efficiency test kit for detecting HSO4− ions with the naked eye.

The detection of volatile aliphatic aldehydes is of significance because of their chemical toxicity, physical volatility and widespread applications in chemical industrial processes. In this work, the direct detection of aliphatic aldehydes is tackled using a pillar[5]arene-based fluorescent supramolecular polymer with vaporchromic behavior. Thin films with strong orange-yellow fluorescence are prepared by coating the linear supramolecular polymer on glass sheets. When the thin films are exposed to aliphatic aldehydes with different carbon chain lengths, they can selectively sensing n-butyraldehyde (C

Supramolecular xerogel films as multicolor photoluminescent materials are ideal for applications in optical devices, such as photochromic smart windows and LEDs. Therefore, a blue-fluorescence supr...

A novel 3D supramolecular polymer network gel (DP5G) was successfully constructed by easy to synthesize tripodal guest (SZ) and thioacetylhydrazone functionalized di-pillar[5]arene host (DP5). Interestingly, the DP5G showed aggregation induced emission (AIE). Moreover, the DP5G displayed a 3D network structure, which was used to dye removal experiments. Notably, the xerogel DP5G could effectively remove cationic dyes (including crystal violet and rhodamine B) from aqueous solution and the removal percentages are 96.3% and 95.4%, respectively. In addition, the maximal adsorption capacity of DP5G towards crystal violet and rhodamine B are 19.65 mg/g and 22.85 mg/g, respectively. The stability of the 3D supramolecular polymer network gel (DP5G) was further investigated, which exhibited excellent stability toward outer stimuli such as pH, competitive agents, oxidant and reducing agent.

An ultrasensitive detection and effective removal material was successfully developed by using a pillar[n]arene-based supramolecular polymer gel (MTP5⊃HB). The MTP5⊃HB can ultrasensitively recognize Cu2+ and Fe3+, and the limits of detection (LODs) for Cu2+ and Fe3+ are 1.55 and 2.68 nmol/L, respectively. Additionally, the in-situ generated metallogel MTP5⊃HB-Cu can exclusively detect CN−, and the LOD for CN− is 1.13 nmol/L. Noticeably, the xerogel of MTP5⊃HB-Cu can effectively remove CN− from aqueous solution with 94.40% removal rate. Test kit based on MTP5⊃HB-Cu is also prepared for convenient detection of CN−.