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Two novel fluorescent probes based on phenothiazine: synthesis and “naked-eye” colorimetric recognition of Hg2+
摘要： Two novel colorimetric and fluorescent probes 2-(1,3-dithiolanes)-10-ethyl phenothiazine (PHE–Ed) and 2-(1,3-dithianes)-10-ethyl phenothiazine (PHE–Pd) based on phenothiazine were successfully synthesized, and their structure was confirmed by NMR and high resolution mass spectra. Fluorescence investigations revealed that the synthesized probes could be used for the selective detection of Hg2+, which was accompanied with an obvious color change from colorless to light yellow. The applicable ability of the two probes was investigated by a series of competitive experiments, solid colorimetric experiments, and applied experiments, which proved that these probes showed high sensitivity and great potential to detect Hg2+ in environmental analysis systems. Furthermore, the detection mechanism of the probes was investigated by FT-IR spectra and NMR spectra, and the results indicated that the detection of Hg2+ was accomplished through the Hg2+-promoted deprotection of thioacetal.
关键词： Phenothiazine,ICT fluorophore,1,3-propanedithiol,Naked-eye,1,2-ethanedithiol
更新于2025-09-23 15:22:29
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Two novel rhodamine-based fluorescent probes for the rapid and sensitive detection of Fe3+: Experimental and DFT calculations
摘要： Fe3+ ions play an important role in both biological and environmental field. In this work, two novel rhodamine-based colorimetric and fluorescent probes (RBA2 and RBA3) were designed and synthesized for the efficient detection of Fe3+. Upon the addition of Fe3+, the fluorescence intensity of RBA2 and RBA3 enhanced 108-fold and 222-fold, respectively. RBA2 and RBA3 exhibited a low detection limit which could achieve 12.8 nM and 11.0 nM. In addition, the binding modes of RBA2 and RBA3 with Fe3+ were proved to be 1:1 stoichiometry in the complexes by Job’s plot, ESI-MS and 1H NMR results. The complexing ability of RBA3 with Fe3+ excessed to that of RBA2 that was determined by the binding association constants, and highly consistent with DFT calculations results. Furthermore, RBA2 and RBA3 were further utilized to detect Fe3+ in living cells and real water samples, indicating their promising prospects in biological and environmental field.
关键词： Cell imaging,DFT calculation,Binding ability,Naked eye,Fe3+
更新于2025-09-23 15:22:29
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Crown-Porphyrin Ligand for Optical Sensors Development
摘要： A novel porphyrin ligand, Zn(II)TPP-BPI-crown (ZnPC), functionalized with two dibenzo-crown-ether moieties was synthesized and tested as cation-sensitive ionophore. Fluorescence studies on ligand sensitivity towards a number of different metal cations (Na+, K+, Li+, Ca2+, Mg2+, Co2+, Cd2+, Pb2+, Cu2+, Zn2+ and NH4+) were carried out first in solution and then inside polymeric membrane optodes. Emission light signal was sufficiently brilliant to be captured by a low-cost computer webcam, while a commercial blue-light LED served as monochromic excitation light source. The influence on the ZnPC optode response of the lipophilic sites functionalization was investigated. The visibly (naked eye) observed color change of sensing material from green to red demonstrated the suitability of the ZnPC-based optodes to perform fast monitoring of Cu(II) ions in the concentration range between 6.6 × 10?7 and 2.4 × 10?2 mol/L with a low detection limit (estimated by s/n = 3 method) of 0.3 mg/L, which is lower than WHO guideline value of 2 mg/L.
关键词： chemical optical sensor,novel Zn(II)-porphyrin ligand functionalized with two dibenzo-crown-ether moieties,naked eye detection of Cu(II) ions
更新于2025-09-23 15:21:01
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The naked-eye NH3 sensor based on fluorinated graphene
摘要： Graphene has aroused continual and tremendous interest in gas sensing applications because of its unique properties. However, the graphene-based sensors still meet limitations such as inconvenient device fabrication, sustained power supply, specific measuring equipment, etc. Here, we find that fluorinated graphene (FG) shows an obvious color change (from white to dark yellow) in the presence of NH3 which can be observed directly by the naked eye. PL measurement shows that the sensitivity of color change can reach a high value of ca. 4.05 % ppm-1. The density functional theory calculations reveal that the F atoms on FG increase the adsorption ability and charge transfer of NH3 molecules, resulting in the efficient color change. This work develops a naked-eye sensor which needs no device fabrication, power supply or measuring equipment, thus, can be potentially used to manufacture a cheap, sensitive and miniaturized NH3 sensor.
关键词： fluorinated graphene,charge transfer,NH3 sensor,naked-eye color change,adsorption ability
更新于2025-09-23 15:21:01
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A novel 1,8-naphthalimide as highly selective naked-eye and ratiometric fluorescent sensor for detection of Hg2+ ions
摘要： A novel colorimetric and ratiometric fluorescent chemosensor, 2-(2-mercaptophenyl)-1H-benzo[de]isoquinoline-1,3-(2H)-dione (L3) is reported for Hg2+ ions. The selective binding of Hg2+ to L3 afforded new absorbance and fluorescence peaks at 438 nm and 480 nm, in addition to the existing bands of L3 at 332 nm and 376 nm. It also showed apparent colour change from colourless to yellowish green and weak fluorescent to bright yellowish green strong fluorescent due to selective binding of Hg2+ ion. The sensor forms a 1:1 stoichiometry with high binding constants (3.89 × 10^4 mol^-1 L) and limit of detection 1.74 × 10^-8 M with high selectivity and sensitivity towards Hg2+ in the presence of other interfering metal ions. More importantly, it has good practicability in environmental water sample. The outcome of photo-physical experiment has also been in good accordance with the time-resolved fluorescence life decays and the density functional theory (DFT) estimations. Moreover, the L3-Hg2+ solution displayed high colorimetric and fluorimetric reversibility via the addition of KI. This reversibility in fluorescence showed potential applicability of chemosensor L3 as 'on–off–on' naked eye sensor.
关键词： Molecular logic gate,Red-shift,DFT,Off–on–off Hg2+ chemosensor,Naked eye detection,Ratiometric fluorescence
更新于2025-09-19 17:15:36
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Real-time naked-eye recognizable temperature monitoring based on Ho <sup>3+</sup> (or Tm <sup>3+</sup> )-activated NaYF <sub/>4</sub> upconversion nanowires <i>via</i> visual multicolor alteration
摘要： Non-contact thermometry for real-time temperature monitoring is a challenging research topic. Advances in microelectronics and biotechnology demand precise temperature monitoring with novel materials and approaches, where conventional thermometers are burdensome because of employing expensive additional equipment (e.g. spectrometers) and further data processing. Lanthanide-doped upconversion nanomaterials that can convert single near-infrared excitation into multicolor visible emissions open the door for a novel strategy to thermometry. Herein, a real-time naked-eye recognizable color change was achieved based on Ho3+ (or Tm3+)-activated NaYF4 upconversion nanowires, depending on the different spectral sensitivities of the blue, green and red upconversion emissions to temperature. Furthermore, the luminescence color can be also directly modulated by only using 975 nm laser radiation, which extended their application scope. These desirable properties make upconversion nanomaterials promising for temperature monitoring, anti-counterfeiting, and multicolor temperature probing applications with the advantages of being simple, convenient and unreplicable.
关键词： nanowires,naked-eye recognizable,upconversion,temperature monitoring,multicolor alteration
更新于2025-09-19 17:15:36
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On the combination of luminescent rare earth MOF and rhodamine dopant with two sensing channels for picric acid
摘要： The present paper reported a hybrid structure for the optical recognition of PA (picric acid). This dye-MOF structure, named as R6h@EuBTC, consisted of a supporting matrix based on rare earth MOF and a sensing probe based on rhodamine dye, which was con?rmed using XRD, IR, thermal and photophysical analysis. R6h@EuBTC's rhodamine absorption in visible region was enhanced by increasing PA concentrations, showing obvious color change and consequently colorimetric sensing. R6h@EuBTC's rhodamine emission component was increased by increasing PA concentrations, while its Eu emission component was slightly quenched by increasing PA concentrations, which offered self-calibrated sensing signals for ratiometric ?uorescent sensing. Linear response and good selectivity were observed for both sensing channels with LOD of 3.9 μM. R6h@EuBTC's sensing mechanism towards PA was the combination of two procedures, which were the emission turn on effect of rhodamine component triggered by PA-released protons and the emission turn off effect of Eu component caused by its electron transfer procedure to PA, respectively. R6h@EuBTC's novelty was its two sensing channels and the practicability of naked eye detection.
关键词： Ratiometric sensing,Optical sensing,Explosive detection,Naked eye detection
更新于2025-09-19 17:15:36
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Metal ion sensing ability and photo-physical properties of 4-hydroxy-3-nitroso-2H-chromen-2-one: Interaction studies with calf thymus-DNA
摘要： 4-Hydroxy-3-nitroso-2H-chromen-2-one (HNC), a coumarin derivative has been synthesized through a very simple method, and its photo-physical properties were studied. HNC is used as a simple colorimetric as well as spectrophotometric chemosensor for the detection of Fe2+, Co2+, Ni2+ and Cu2+ ions, some even by naked-eyes. This process gives a sensitive readout of chemosensor HNC within a wide range of (4.5–1219.5) × 10?7 (M) at λmax 258 nm. HNC has greater binding and detection ability toward Fe2+ than that of 1,10-phenanthrolin, and it has greater binding ability for Fe2+ than that with Fe3+ also. We have also established a method for solid state sensing of iron salts by HNC. Moreover, the binding interaction of HNC with calf-thymus DNA (CT-DNA) established a groove binding mode.
关键词： CT-DNA,Coumarin,Solid state Fe2+ ion sensing,Naked-eye metal sensing,Chemosensor
更新于2025-09-10 09:29:36