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Kinetics of singlet oxygen sensing using 9-substituted anthracene derivatives$$^{\#}$$#
摘要： Singlet oxygen (1O2), the lowest excited-state of molecular oxygen receives great attention in basic research and clinical and industrial settings. Despite several spectroscopic methods available for 1O2 sensing, fluorescence sensing receives great attention, for which many fluorogenic sensors based on substituted anthracene are reported. Nonetheless, the roles of substituents on the sensing efficiency, in terms of detection time, remain largely unknown. In this work, we examine the 1O2 sensing efficiency of a fluorescence sensor based on a coumarin–anthracene conjugate, which is an electron donor-acceptor dyad, and compare the efficiency with that of 9-methylanthracene. Here, 1O2 is generated using the standard photosensitizer Rose Bengal, which is followed by estimation of the rate of reaction of 1O2 to the sensor and 9-methylanthracene. The second order reaction rate of the sensor is an order of magnitude less than that of 9-methylanthracene. The lower reactivity of the sensor to 1O2 suggests that the roles of substituents, such as electronic interactions, steric interactions and the reactivity of precursor complexes, on sensing efficiency should be carefully considered during construction of fluorogenic molecular sensors.
关键词： photochemistry,reaction kinetics,anthracene,fluorescence sensing,Singlet oxygen
更新于2025-09-23 15:23:52
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Anthracene-based cyclophanes with selective fluorescent responses for TTP and GTP: insights into recognition and sensing mechanisms
摘要： Three anthracene-based cyclophanes have been synthesized and their binding properties towards nucleoside triphosphates have been studied. A new polycyclic amine derived from dearomatized anthracene has been identified as a major side product in the reaction between 9,10-anthracenedicarboxaldehyde and diethylenetriamine. Its structure has been determined by the single crystal X-Ray analysis. The cyclophanes have been found to form 1:1 complexes with all nucleoside triphosphates as well as with pyrophosphate in a buffered aqueous solution at pH 6.2. A turn-on fluorescence response has been observed for all nucleotides except for GTP, which demonstrated strong fluorescence quenching. The strongest turn-on fluorescence answer has been observed for the largest receptor 3 in the presence of TTP. Based on the NMR and fluorescence experiments two major binding modes for nucleotide complexes have been identified.
关键词： macrocycle,host-guest chemistry,nucleotide recognition,synthetic receptor,fluorescence sensing
更新于2025-09-23 15:22:29
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Preparation and Characterization of Metal-Organic Frameworks and its Composites Eu <sub/>2</sub> O <sub/>3</sub> @[Zn <sub/>2</sub> (bdc) <sub/>2</sub> dabco] (ZBDh) via Pulsed Laser Ablation in Flow Liquid
摘要： This work reports the compounds of [Zn2(bdc)2dabco] (ZBDh) and [Zn2(bdc)2dabco] (ZBDt) and the composite Eu2O3@[Zn2(bdc)2dabco](ZBDh) synthesized by pulsed laser ablation in flowing liquid. At an appropriate reactants concentration of reactants, the phase ZDBh transforms into phase ZDBt by an increase of the irradiation time from 4 to 40 mins. The results show that the Eu2O3 nanoparticles with an average size of 3.17 nm are uniformly distributed among the crystal and the BET specific surface area of the composite Eu2O3@[Zn2(bdc)2dabco] (ZBDh) is 1621 m2/g, which is larger than that of compound [Zn2(bdc)2dabco] (ZBDh). Moreover, the composite Eu2O3@[Zn2(bdc)2dabco](ZBDh) can emit very intense characteristic fluorescence at 613 nm of Eu3+ ion under ultraviolet radiation and can be used for detecting of methanol molecules in fluorescence sensing because of its fluorescence intensity at 613 nm is sensitive to the content of methanol in solvent.
关键词： pulsed laser ablation,metal-organic frameworks,Eu2O3 nanoparticles,fluorescence sensing,methanol detection
更新于2025-09-23 15:21:01
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Design of High-Symmetrical Magnesium-Organic Frameworks with Acetate as Modulator and Their Fluorescence Sensing Performance
摘要： During the formation of magnesium-organic frameworks, the coordination sphere of magnesium tends to be partially occupied by O-containing solvent molecules such as amides, which will dramatically decrease the symmetry of Mg-organic frameworks and thus lead to low stability. It is noted that up to now, most reported Mg-metal?organic frameworks (MOFs) (>80%) crystallize in the space groups whose symmetry is lower than that of a tetragonal system. In this work, we demonstrate that acetate (Ac) may act as modulator to eliminate the influence of amide solvent and improve the symmetry of Mg-organic frameworks. Two novel Mg-MOFs, namely, {[(CH3)NH3]4[Mg3(BTB)8/3(Ac)2(H2O)]}n (SNNU-35, H3BTB = 4′,4′′,4′′′-benzene-1,3,5-tribenzoic acid) and {[(CH3)2NH2][Mg2(FDA)2(Ac)]}n (SNNU-36, H2FDA = 2,5-furandicarboxylic acid) were successfully designed, which crystallize in rhombohedral R-3 and tetragonal I4/mmm space groups, respectively. Four independent BTB ligands link three unique Mg cations and generate superlarge [Mg21BTB17] nanocages, which interlock each other by strong π···π stacking to give a two-fold interpenetrating architecture of SNNU-35. On the other hand, carboxylate and acetate groups chelate Mg atoms to form one-dimensional chains, which are extended by FDA to produce the rod-packing framework of SNNU-36. Two microporous Mg-MOFs both exhibit notable CO2 and H2 uptakes. H3BTB and H2FDA ligands both have emission features, and Mg ions usually can enhance the fluorescent intensity, which lead to a strong solid-state luminescence emission property of SNNU-35 and -36. Importantly, two Mg-MOFs both show fast and quantative sensing performance for nitrocompounds. Among three selected models of substrate, SNNU-35 and -36 can eliminate the interference of nitromethane (NM) and exhibit high sensitivity to nitrobenzene (NB) and o-nitrotoluene (2-NT) with large ksv values (>105 M?1). Especially, the fluorescence quenching efficiency of NB (5000 ppm) and 2-NT (8000 ppm) can reach 96.3% and 89.5% and 85.0% and 83.7% for SNNU-35 and -36, respectively. This work offers not only an effective route to improve the symmetry of magnesium-organic frameworks but also two potential fluorescence sensors for nitroaromatic compounds.
关键词： magnesium-organic frameworks,nitrocompounds,fluorescence sensing,modulator,acetate
更新于2025-09-23 15:21:01
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Dual Functional S-Doped g-C3N4 Pinhole Porous Nanosheets for Selective Fluorescence Sensing of Ag+ and Visible-Light Photocatalysis of Dyes
摘要： This study explores the facile, template-free synthesis of S-doped g-C3N4 pinhole nanosheets (SCNPNS) with porous structure for fluorescence sensing of Ag+ ions and visible-light photocatalysis of dyes. As-synthesized SCNPNS samples were characterized by various analytical tools such as XRD, FT-IR, TEM, BET, XPS, and UV–vis spectroscopy. At optimal conditions, the detection linear range for Ag+ was found to be from 0 to 1000 nM, showing the limit of detection (LOD) of 57 nM. The SCNPNS exhibited highly sensitive and selective detection of Ag+ due to a significant fluorescence quenching via photo-induced electron transfer through Ag+–SCNPNS complex. Moreover, the SCNPNS exhibited 90% degradation for cationic methylene blue (MB) dye within 180 min under visible light. The enhanced photocatalytic activity of the SCNPNS was attributed to its negative zeta potential for electrostatic interaction with cationic dyes, and the pinhole porous structure can provide more active sites which can induce faster transport of the charge carrier over the surface. Our SCNPNS is proposed as an environmental safety tool due to several advantages, such as low cost, facile preparation, selective recognition of Ag+ ions, and efficient photocatalytic degradation of cationic dyes under visible light.
关键词： cationic dyes,pinhole porous nanosheet,photocatalytic degradation,visible light,Ag+ ions,S-doped g-C3N4,fluorescence sensing
更新于2025-09-19 17:15:36
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One-step preparation of single-layered graphene quantum dots for the detection of Fe3+
摘要： Single-layer graphene quantum dots are highly desirable while their facile and controllable preparations remain challenging. Herein, single-layered graphene quantum dots (sl-GQDs) were developed via a facile one-step hydrothermal synthesis, with citric acid and β-cyclodextrin (CD) as starting materials. The sl-GQDs decorated with CD molecules emit green fluorescence with a quantum yield of 5.34%, and exhibit a good response exclusively to ferric ions for their structural oxygenous groups. The linear range of the proposed sensor for ferric ions was found in a wide concentration range of 0-85 μM. The detection limit is about 0.26 μM. The sl-GQDs based sensing platform also demonstrates its feasibility in real water sample analysis with recoveries of 93.8%-101.5%.
关键词： One-step preparation,β-cyclodextrin,Fluorescence sensing,Single-layered graphene quantum dots,Ferric ion
更新于2025-09-19 17:13:59
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A Self‐Assembled Peptide‐Appended Naphthalene Diimide: A Fluorescent Switch for Sensing Volatile Acid and Basic Vapors
摘要： A histidine-containing peptide-appended naphthalenediimide (NDI) based bola-amphiphilic molecule (NDIP) has been found to form fluorescent hydrogel in phosphate buffer and organogels with benzenoid solvents. These gels were characterized by several spectroscopic and microscopic technique like FT-IR, HR-TEM, powder X-ray diffraction and small-angle X-ray scattering, UV-Vis and fluorescence studies. The gelator molecule exhibits no significant fluorescence in the xerogel state, while it turns into a significant fluorescent (bright cyan) color in presence of volatile organic/inorganic acid vapors and this cyan color vanishes in presence of base (ammonia vapors). A paper strip based method is able to detect hazardous volatile acid and base vapors using this self-assembled fluorescent material that is economically viable, easily detectable through a naked eye and reusable several times.
关键词： self-assembly,fluorescence sensing,naphthalene diimides,peptides,hydrogel
更新于2025-09-11 14:15:04
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A Bifunctional Luminescent Coordination Polymer as Recyclable Sensor for Detecting TNP and Fe3+ with High Selectivity and Sensitivity
摘要： A thermo-stable three dimensional network [Cd2(BPDPE)2(1,2-H2bdc)2]n (1) (1,2-H2bdc = 1,2-benzenedicarboxylic acid, BPDPE = 4,4′-bis(pyridyl)diphenyl ether) with blue fluorescence was successfully synthesized and characterized. Complex 1 is a two-dimensional layer constructed by BPDPE connecting [Cd(1,2-bdc)]n one-dimensional chains, then a three-dimensional network is finally formed via π···π interactions. Importantly, Complex 1 presents an excellent fluorescent MOF sensor for highly sensitive and selective detecting TNP, the Ksv is up to 1.03×105 M-1. Further more, complex 1 can be quickly regenerated by simple washing, exhibiting good recyclability for detecting TNP. In addition, complex 1 shows higher sensitive fluorescent sensor for detecting Fe3+ cation than other metal ions. the Ksv is calculated to be 1.84×105 M-1. Furthermore, the quenching mechanisms of complex 1 as bifunctional sensor were studied as well.
关键词： Nitro aromatic explosives,Selectivity and sensitivity,Fluorescence sensing,Metal ions,Coordination polymer
更新于2025-09-10 09:29:36
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A novel luminescent 1D→2D polyrotaxane Zn(II)-organic framework showing dual responsive fluorescence sensing for Fe3+ cation and Cr(VI) anions in aqueous medium
摘要： A novel hydrolytic stable Zn(II)-organic framework {[Zn(afsba)(bbtz)1.5(H2O)2]·2H2O}n (1) based on the amino/sulfonato-functionalized ligand 2-amino-5-sulfobenzoic acid (H2afsba) and the auxiliary flexible ligand 1, 4-bis(triazol-1-ylmethyl)benzene (bbtz) was constructed hydrothermally. Single-crystal X-ray diffraction analysis reveals that 1 shows a novel 1D→2D polyrotaxane framework architecture. The detailed analysis of the solid state diffuse reflectance UV-vis spectrum of 1 reveals that it may be used as a potential wide band gap semiconductor material. 1 exhibits reversible dehydration-rehydration behavior. 1 manifests distinct solvent-dependent fluorescence properties. The strongest fluorescence is observed in water. 1 keeps excellent framework stability in a variety of solvents. Interstingly, 1 shows highly selective and efficient sensing of the Fe3+ cations over a variety of the interfering metal cations in both environment and biological systems. 1 could also be used as a potential highly selective and sensitive sensory material for the Cr(VI) (CrO4 2?/Cr2O7 2?) anions among a large pool of the coexistent different anions. The limits of 1 for the aqueous-phase sensing of these analytes reach to sub-ppm level (0.22 ppm/0.26 ppm for CrO4 2?/Cr2O7 2- and 0.07 ppm for Fe3+, respectively).
关键词： dual responsive fluorescence sensing,Fe3+ cation,Zn(II)-organic polyrotaxane framework,Cr(VI) anions
更新于2025-09-10 09:29:36
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Comprehensive Supramolecular Chemistry II || Fluorescence Sensing With Functional Nucleic Acids
摘要： A few years after the ground-breaking discovery that RNA can function as enzymes, a powerful technique was devised that enabled researchers to search through large random-sequence DNA and RNA pools for “functional nucleic acids (FNAs)” with tailor-made ability to recognize a target of interest or to catalyze a chosen chemical reaction. This technique is now widely known as “in vitro selection” or “SELEX” (which stands for “Systematic Evolution of Ligands by EXponential enrichment”). Such experiments always start with an extraordinarily large pool containing up to 1016 different DNA or RNA sequences. A small number of the sequences in the pool are separated based on their ability to perform the targeted binding or catalytic function. The isolated sequences are multiplied using nucleic acid amplification techniques. The resulting pool, now much more abundant with functional species, is then used to restart the same cycle. Iterating this process for many rounds leads to the enrichment of a few species that are proficient at performing the desired activity.
关键词： Functional nucleic acids,biosensing,SELEX,fluorescence sensing,in vitro selection
更新于2025-09-10 09:29:36