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A new multi-analyte fluorogenic sensor for efficient detection of Al <sup>3+</sup> and Zn <sup>2+</sup> ions based on ESIPT and CHEF features
摘要： The fluorogenic chemosensor 3-(((2-hydroxy-4-methylphenyl)imino)methyl)-[1,10-biphenyl]-4-ol (H2L) efficiently detects Zn2+ and Al3+ ions and subsequently fluoride ion in methanol–water (4/1, v/v, pH = 7.2) solution. The probe itself is non-emissive but upon treatment with Al3+ and Zn2+, it exhibits high fluorescence emission at two different wavelengths of 546 nm and 529 nm, respectively. Both excited-state intramolecular proton transfer (ESIPT) and chelation enhanced fluorescence (CHEF) processes play important roles in the enhancement of fluorescence intensity. Chelation of Zn2+ and Al3+ with the probe (H2L) inhibits CQN isomerization and ESIPT which consequently enhances the emission intensity. The emission intensity of H2L–Al3+ is selectively quenched upon titration with F- anions. The structure of the probe is confirmed by the single crystal X-ray diffraction method. The electronic structure and sensing mechanism of the probe (H2L) are supported by density functional theory (DFT) and time-dependent density functional theory (TDDFT).
关键词： Zn2+ detection,fluoride detection,CHEF,fluorogenic sensor,ESIPT,Al3+ detection
更新于2025-11-19 16:46:39
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A colorimetric, ultraviolet absorption and fluorescence three-signal probe based on bis-carbazole for Al3+ detection and the application in cell imaging
摘要： A novel Schiff-base, [9-(2-Chloro-ethyl)-9H-carbazol-3-yl-methylene]-(9-ethyl-9H-carbazol-3-yl)-amine (CECA) was designed and synthesized, which was highly selective and sensitive for the detection of Al3+ by colorimetric, ultraviolet absorption and fluorescence three-signal methods. The detection limit was evaluated to be as low as 74 nmol/L for the ultraviolet absorption method and 19 nmol/L for fluorometric method. These three methods could determine qualitatively and quantitatively the concentrations of Al3+ and been used in different conditions. The mechanism was explored that the double bond (C=N) of CECA was broken to form the carbazole aldehyde and carbazole amine complex accompanied by fluorescence enhancement by the Job's plot, 1H NMR, the electrospray ionization mass spectra (EI-MS) and fluorescence methods. More significantly, the fluorescence imaging showed that CECA could detect Al3+ in living cells.
关键词： Schiff base,Al3+,Detection,Imaging,Three-signal
更新于2025-11-14 15:29:11
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Luminescence Tuning of Layered Rare-Earth Hydroxides (LRHs, R = Tb, Y) Composites with 3-Hydroxy-2-naphthoic Acid and Application to the Fluorescent Detection of Al <sup>3+</sup>
摘要： Tunable luminescence (quenching or blue shift) of HNA/OS-LRH composites (HNA is 3-hydroxy-2-naphthoic acid; OS is the anionic surfactant of 1-octanesulfonic acid sodium; LRHs are layered rare-earth hydroxides, R = Tb3+, Y3+) in the solid state and delaminated state is reported, which is utilized as an effective fluorescent probe for detecting metal ions. HNA/OS species are intercalated into LRH layers to generate composites of HNAxOS1?x-LTbH (x = 0.10, 0.15, 0.20 , 0.25) and HNAyOS1?y-LYH (y = 0.05, 0.10, 0.15, 0.20, 0.25, 0.30). In the solid state, LYH composites exhibit green emissions (from 493 to 504 nm) with a large blue shift in comparison to the 542 nm emission of free HNA? anions, while in the delaminated state in formamide (FM), the composites display blue emission (480 nm) relative to the green emission (512 nm) of an HNA soltuion in FM. However, LTbH composites display coquenched luminescence in both the solid state and delaminated state. Also, HNA0.25OS0.75-1:1-LYH, HNA0.25OS0.75-1:2-LYH, and HNA0.05OS0.95-1:1-LYH (1:1 and 1:2 are HNA:NaOH molar ratios) show significantly elongated fluorescence lifetimes of 15.35, 14.37, and 12.72 ns, respectively, in comparison with free HNA-Na (6.44 ns), and their quantum yields of 23.40%, 21.97%, and 22.31%, respectively, are much larger than that of free HNA-Na (4.86%). The LTbH composite (HNA0.25OS0.75-1:1-LTbH) has also a relatively higher quantum yield of 12.46%. The HNA0.25OS0.75-1:1-LYH colloid exhibits excellent recognition selectivity for Al3+ over other metal ions (Mg2+, Co2+, Ni2+, Cu2+, Zn2+, Pb2+, Cd2+, and Hg2+) with distinct fluorescence sensitization. It shows an intense change in its fluorescence emission when it is bound to Al3+ ions, giving a lower detection limit of 6.32 × 10?6 M. This is novel research on the fluorescence chemosensing of LRH composites.
关键词： Layered rare-earth hydroxides,Fluorescent detection,Chemosensing,Luminescence tuning,Al3+ ions
更新于2025-11-14 15:28:36
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Significant improved selectivity of a fluorescent sensor for Al3+ made from a fluorinated rhodamine B Schiff base
摘要： Two rhodamine B-based Schiff bases (RBF, RBC) with different substituent groups (–F and –COOH) have been synthesized. In order to study the sensing properties of two Schiff bases for metal ions, the interaction of Schiff bases with different metal ions was studied over UV–Vis absorption spectra and photofluorescent spectra. The results show that the RBF is a turn-on fluorescent chemosensor for Al3+ ions with being highly selective and sensitive in ethanol. The value of the fluorescence increase factor shows a good linear relationship with the concentration of Al3+ in the range of 1–9 μM with a detection limit of 0.8 μM. Meanwhile, upon addition of Al3+ or Fe3+ ions, the fluorescence intensity of RBC increased significantly (FAl3+/FFe3+ = 0.77). These studies show that, compared with the carboxyl group (–COOH), the introduction of fluorine atoms (–F) to a rhodamine B-based Schiff base can significantly improve selectivity to Al3+.
关键词： Al3+ ion,Fluorine atoms,Fluorescent sensor,Rhodamine B
更新于2025-09-23 15:23:52
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A selective diaminomaleonitrile-based dual channel emissive probe for Al3+ and its application in living cell imaging
摘要： A selective diaminomaleonitrile-based fluorescent probe for Al3+(L) has been synthesized and characterized. The sensing behavior of L towards different metal ions was investigated by fluorescent spectra and competition experiment. The results showed that L exhibited a dual channel emission (λem 522 & 558 nm) with yellow fluorescence in the presence of Al3+ over other metal ions in EtOH solution. The probe L was bound to Al3+ in a 1: 2 stoichiometric manner as supported by Job’s plot analysis. The binding constant was 9.55×108 M-2 with the detection limit of 10.3 nM. The turn-on response was attributed to the inhibition of PET and C=N isomerization after binding with Al3+ while the dual emissions were due to ESIPT and ICT processes. In addition, the application of L for imaging Al3+ in living Hela cells was achieved.
关键词： diaminomaleonitrile-based,Al3+,living cell imaging,selective,dual channel
更新于2025-09-23 15:22:29
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Self-Assembly of Amphiphilic Schiff Base and Selectively Turn on Circularly Polarized Luminescence by Al3+
摘要： We designed glutamide-derived amphiphilic Schiff bases containing three different aldehyde moieties for the fabrication of circularly polarized luminescence (CPL) emitting materials. Upon self-assembly in acetonitrile, Schiff bases featuring 4-(dimethylamino)-2-hydroxylbenzaldehyde and 1-hydroxy-2-naphthaldehyde groups form supramolecular gels with twist and fiber structures, respectively, while Schiff bases featuring 2-hydroxy-1-naphthaldehyde groups forms precipitation with flakes structures. Although emission and circular dichroism (CD) signals can be detected from the supramolecular gels formed by amphiphilic Schiff bases, none of them exhibits circularly polarized luminescence (CPL). While Mg2+, Zn2+ and Al3+ can both significantly enhance the fluorescence of the Schiff bases, interestingly, only Al3+ ion is able to turn on the CPL emission. This study on the one hand provides a simple method to the fabrication of CPL emitting supramolecular materials, and on the other hand offers a novel way to the sensing of aluminum ion with supramolecular materials.
关键词： Self-assembly,Schiff bases,Circularly polarized luminescence,Al3+,Supramolecular gels
更新于2025-09-23 15:21:21
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Investigation on the mechanism of ESIPT of 2-hydroxy-1-naphthaldehyde-(4-pyridinecarboxylic)- hydrazone and detection of Al<sup>3+</sup> ion
摘要： The sensing mechanism of 2-hydroxy-1-naphthaldehyde-(4-pyridinecarboxylic)-hydrazone for Al3+ is investigated based on the excited-state intramolecular proton transfer (ESIPT) and photo-induced electron transfer (PET) processes. Absorption and fluorescence spectra are calculated, which are well consistent with experimental results. By analyzing the major bond parameters, infrared (IR) vibrational spectra as well as frontier molecular orbitals (MOs), it can be concluded that the hydrogen bond is enhanced in the first singlet excited state (S1), which can also be visualized by the reduced density gradient function. Potential energy curves (PECs) are also scanned, which can elucidate that the ESIPT process is more likely to occur in the S1 state. Changes in molecular configuration and intensity of fluorescence emission confirmed that the ESIPT and PET processes are forbidden in the presence of Al3+.
关键词： ESIPT,Hydrogen bond,Reduced density gradient,Potential energy curve,Al3+ sensing
更新于2025-09-23 15:21:01
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A novel coumarin-based fluorescence chemosensor for Al3+ and its application in cell imaging
摘要： As an efficient turn-on fluorescent chemosensor for Al3+, a new coumarin derivative (CND) has been designed and synthesized by the condensation of 8-formyl-7-hydroxycoumarin with niacin hydrazide. The spectroscopic studies revealed that the sensor CND exhibited a remarkable fluorescence enhancement towards Al3+ with high selectivity and sensitivity in EtOH-HEPES (95:5, v/v, pH = 7.40), which was attributed to the photoinduced electron transfer (PET) and -C=N isomerization mechanism. Fluorescence titration calculations data showed that the detection limit and the association constants of CND for Al3+ were found to be 2.51×10-7 M and 9.64×104 M-1, respectively. The results of experiments, including Job,s plot, 1H NMR titration and ESI-MS, revealed that the stoichiometric binding between CND and Al3+ was 1:1. The investigations of the pH dependency of CND for Al3+ detection, and the cell imaging suggested the sensor CND could be promisingly applied for the recognition of Al3+ in biological cells.
关键词： chemosensor,coumarin,live cells,Al3+
更新于2025-09-23 15:21:01
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Self-agglomerated crystalline needles harnessing ESIPT and AIEE features for the ‘turn-on’ fluorescence detection of Al <sup>3+</sup> ions
摘要： We report the synthesis of probe 2 for the fluorescence "turn-on" detection of Al3+ ions in CH3OH. Probe 2 has been designed via utilizing the aggregation-induced emission properties of the tetraphenylethylene unit, with further enhancement from Schiff base units for the ESIPT phenomenon. Probe 2 exhibits emission at 548 nm (lex = 360 nm), with a large Stokes shift of 188 nm, indicating the ESIPT phenomenon. Probe 2 also exhibits emission enhancement via increasing the H2O ratio up to 70–90% H2O/THF (v/v) and altering the spherical morphology to needle shapes. Probe 2 has been found to be highly selective and sensitive towards Al3+ ions over other metal ions in pure CH3OH using absorption and emission spectroscopy. FESEM analysis revealed that the size of probe 2 increases upon the addition of Al3+ ions. Thus, the fluorescence "turn-on" behaviour of probe 2(cid:2)Al3+ is due to metal-induced aggregation.
关键词： fluorescence detection,ESIPT,Al3+ ions,AIEE,aggregation-induced emission
更新于2025-09-19 17:15:36
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An efficient new dual fluorescent pyrene based chemosensor for the detection of bismuth (III) and aluminium (III) ions and its applications in bio-imaging
摘要： A new simple pyrene based schiff base chemosensor 1 (nicotinic acid pyren-1-ylmethylene-hydrazide) has been constructed and is prepared from 1-pyrenecarboxaldehyde and nicotinic hydrazide. Notably, the chemosensor 1 exhibited remarkable colour changes while in the presence of trivalent metal ions like Bi3+ & Al3+ ion in DMSO-H2O, (1:1 v/v, HEPES = 50 mM, pH = 7.4). The UV-Vis spectral investigation of chemosensor 1 showed that the maximum absorption peak appeared at 378 nm. In emission studies, chemosensor 1 develops weak fluorescence, while upon the addition of Bi3+ and Al3+ ions, it exhibits an enhancement of fluorescence intensity. Nevertheless, rest of metal ions have no changes in the emission spectra. The association constant of chemosensor 1 for binding to Bi3+ & Al3+ system had a value of 1.27 × 104 M-1 and 1.53 × 104 M-1. The detection limits were 0.12 μM for Bi3+ and 0.17 μM for Al3+ respectively. The overall results reveal that chemosensor 1 can act as a dual-channel, highly selective, and sensitive probe for Bi3+ and Al3+ ions. Moreover, the fluorescence imaging of chemosensor 1 was applied in RAW 264.7 cell line and cytotoxicity assay prove that this chemosensor 1 is non-toxic as well as highly biocompatible.
关键词： Pyrene Schiff base,Spectroscopic studies,Live cell imaging,PET,Bi3+ and Al3+ detection
更新于2025-09-19 17:15:36