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Formaldehyde (HCHO) is a common chemical raw material that is toxic and harmful in nature. Excessive HCHO content has extremely significant effects on the atmospheric environment and human health. To this end, herein, we report a 1H-[1,2,3]triazole[4,5-b]phenazine (PHTA) probe that is capable of sensing HCHO via a rapid change in its fluorescence color or intensity in the presence of the gas and solution. PHTA was directly loaded on a silica gel plate to make a portable solid sensor HCHO kit, which achieves the sensitive and selective detection of gaseous and liquid HCHO. Whether as a solid or liquid sensor for HCHO, PHTA allows for safer and more convenient use compared to other sensors. 1H-[1,2,3]triazole[4,5-b]phenazine, Fluorescent sensor, VOCs, Formaldehyde detection. [ABSTRACT FROM AUTHOR]

Phenazine derivatives have made significant progress owing to their favorable photophysical and chemical properties in recent years. Nevertheless, only a few overviews on phenazine derivatives are reported in the optoelectronic area. Herein, we comprehensively summarize and discuss the tremendous progress on the innovative design strategies, excellent properties and promising applications of novel functionalized phenazine derivatives in optical sensing and electrochemical fields. We anticipate that this review will facilitate new researchers to expand their horizons on the molecular design and development of advanced materials in the future. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Phenazine exhibiting an electron-deficient skeleton, lone pair of electrons on nitrogen atoms, and other properties (such as tunable structures, excellent optical performance and proper binding abilities) can effectively sense target ions or molecules via non-covalent interactions, involving hydrogen bonds, anion–π interactions, metal coordination and other weak forces. These distinct characteristics enable phenazine derivatives to be available in variety of sensors, which have already been demonstrated successfully in the field of sensing. More importantly, phenazine derivatives can be potentially applied in biosensors. Therefore, the latest progress related to the application of phenazine derivatives in optical sensing is summarized. It is expected that phenazine derivatives will garner much interest in the fabrication of sensors and bio sensing applications in the near future. [ABSTRACT FROM AUTHOR]

A supramolecular sensor (APRA–G) was successfully constructed via host–guest interactions between a rhodamine hydrazone functionalized pillar[5]arene (APRA) and a bis-pyridinium derivative (G), which showed highly selective and sensitive detection of toxic Hg2+ through a dual-channel (colorimetric and fluorescent) model. The detection limits of fluorescence and UV-vis spectroscopy towards Hg2+ were 1.69 × 10−8 M and 4.07 × 10−7 M, respectively, which were calculated using the 3σ method. Interestingly, APRA–G could act as an excellent material for Hg2+ separation. Based on ICP (including inductively coupled plasma) data, the separation percentage of the supramolecular sensor (APRA–G) for mercury ions was up to 99.68%. [ABSTRACT FROM AUTHOR]

In this work, a novel supramolecular π-gel has been constructed using a naphthalimide functionalized pillar[5]arene-based gelator (MP5). The gelator MP5 simultaneously contains a naphthalimide moiety as the π…π interaction site as well as a fluorophore. Interestingly, the MP5-based supramolecular π-gel (MP5-G) exhibits strong aggregation-induced emission (AIE). MP5-G exhibited good thermal-responsiveness, acid and base-responsiveness and cation and amino acid-responsiveness. Meanwhile, this supramolecular π-gel also shows selective fluorescence sensing for Fe3+via cation–π interactions with high selectivity and sensitivity, and the detection limit of MP5-G for Fe3+ is 6.06 × 10−8 M. Even more meaningfully, MP5-G could remove Fe3+ from water solution with excellent recyclability and ingestion capacity, and the Fe3+ removal rate can reach up to 99.8%. Furthermore, the Fe3+ coordinated supramolecular gel, MP5-FeG, shows selective fluorescence “turn-on” sensing for l-Cys. The detection limit of MP5-FeG for l-Cys is 1.0 × 10−8 M. Simultaneously, thin films based on these supramolecular gels were prepared, which were confirmed to be convenient test kits for detecting Fe3+ and l-Cys. In addition, these supramolecular π-gels could be used as sensitive ion sensors, sensitive logic gates and fluorescent display materials. [ABSTRACT FROM AUTHOR]

In this study, we prepared an efficient chemosensor based on 2,3-diaminophenazine hydrochloride, and it exhibited good dissolvability in water; more importantly, it could act as an efficient chemodosimeter for the selective detection of CN− in pure water. Upon reacting with CN−, 2,3-diaminophenazine hydrochloride (Q1) displayed a remarkable visible and fluorescence response simultaneously with significant changes in both absorption and fluorescence spectra. Furthermore, the absorption and fluorescence detection limits of CN− were 1.95 × 10−7 M and 1.13 × 10−9 M, respectively. For practical applications, test strips based on this chemosensor could serve as convenient CN− detection tools. The chemosensor was also successfully applied to the detection of CN− in plant seeds and several natural water samples. [ABSTRACT FROM AUTHOR]

A novel approach to achieve ultrasensitive response was successfully developed by rationally introducing the competition between cation–π and exo-wall π–π interactions into a pillar[5]arene-based supramolecular organogel (P5N-OG). Interestingly, the P5N-OG could be used for ion detection and separation, fluorescent display materials as well as ultrasensitive logic gates. [ABSTRACT FROM AUTHOR]

In this study, we developed a novel chemosensor (ATS) that contains the 5-(4-nitrophenyl)-2-furan group and α-naphthylamine for the dual-channel sensing of mercury ions. Under attack from mercury ions, the probe undergoes a blocked process; moreover, it broke the intramolecular charge transfer (ICT) state of the chemosensor, which can be confirmed by 1H NMR, IR and MS studies. We designed this probe to produce a significant change in the color and fluorescence intensity that can achieve naked eye recognition. The experimental results proved that the 5-(4-nitrophenyl)-2-furan group is a very good chromophore. In addition, the ICT state inhibited the fluorescence of naphthylamine. The fluorescent intensity changed significantly when naphthylamine was released. Moreover, high selectivity experiments revealed that the fluorescent sensor is specific to mercury ions even with interference by high concentrations of other metal ions. The test strips based on ATS were fabricated, which could act as a convenient and efficient mercury ion test kit. [ABSTRACT FROM AUTHOR]

Here we report sensitive and selective detection of TNT based on plasmonic resonance energy transfer from a gold nanoplasmonic probe to conjugated target TNT molecules, leading to quenching on the Rayleigh scattering spectrum of the probe. [ABSTRACT FROM AUTHOR]

A supramolecular sensor (APRA–G) was successfully constructed via host–guest interactions between a rhodamine hydrazone functionalized pillar[5]arene (APRA) and a bis-pyridinium derivative (G), which showed highly selective and sensitive detection of toxic Hg2+ through a dual-channel (colorimetric and fluorescent) model. The detection limits of fluorescence and UV-vis spectroscopy towards Hg2+ were 1.69 × 10−8 M and 4.07 × 10−7 M, respectively, which were calculated using the 3σ method. Interestingly, APRA–G could act as an excellent material for Hg2+ separation. Based on ICP (including inductively coupled plasma) data, the separation percentage of the supramolecular sensor (APRA–G) for mercury ions was up to 99.68%. [ABSTRACT FROM AUTHOR]

Supramolecular gels have been widely reported on account of their unique superiority and application prospects. In this work, we constructed a novel supramolecular gel (HD-G) by using hydroxy-naphthaldehyde decorated with naphthalimide in DMSO solution, which exhibited excellent selectivity and ultrasensitive sensing properties toward CN - (the lowest detection limit is 1.82 × 10 -10 M). The sensing mechanism of this supramolecular gel takes advantage of π-π stacking interactions and anion-π interactions, which is different from the other familiar methods.