Synthesis and Application of Specific N2H4 Fluorescent Probes with AIE Effect Based on Pyrazole Structure.

Two fluorescent probes, Y1-2 were synthesized from 2-acetonaphthone, 4-acetylbiphenyl, and phenyl hydrazine by Vilsmeier-Haack reaction and Knoevenagel condensation. Their recognition efficacies for N2H4 were tested by UV-visible absorption spectroscopy and fluorescence emission spectroscopy. The recognition mechanism were studies by density-functional theory calculations, and the effect of pH on N2H4 recognition was also studied. The results showed that the probe Y1-2 has high selectivity and a low detection limit for N2H4, and the recognition of N2H4 can be accomplished at physiological pH. The probes have had obvious aggregation-induced luminescence effect, large Stokes shift, high sensitivity, and can be successfully applied to live cell imaging.

Novel Bis-pyrazoline Fluorescent Probe for Cu2+ and Fe3+ Detection and Application in Cell Imaging.

A fluorescent probe Y((1,1'-([1,1'-biphenyl]-4,4'-diylbis(3-(2-hydroxyphenyl)-4,5-dihydro-1H-pyrazole-5,1-diyl)) bis(ethan-1-one))) was designed and synthesized, which could be used to Cu2+ and Fe3+ sensors. Through the study of optical properties, the probe Y shows good selectivity and sensitivity to Cu2+ and Fe3+ in aqueous tetrahydrofuran solution [10.0 mM HEPES, pH 7.4, THF-H2O = 9:1(v/v)] with has excellent anti-interference performance, and its detection limits were 0.931 uΜ for Cu2+ and 0.401uΜ for Fe3+. The coordination mechanism of probe Y with Cu2+ and Fe3+ was speculated and verified at DFT level and HRNM. By Hela cytotoxicity and imaging tests, probe Y not only has good biocompatibility, but also can be used for sensing Cu2+ in cells.

Bis-chalcone Fluorescent Probe for Hydrazine Ratio Sensing in Environment and Organism.

In this paper, four novel hydrazine fluorescent probes X1-X4 with bis-chalcone structure were designed and synthesized. Through the measurement of its optical properties, it is found that it can quickly identify hydrazine, high sensitivity, low detection limit, and good anti-interference ability. The recognition of hydrazine by probes X1-X4 is not affected in the pH range of 4-10, X2 has the highest sensitivity, and the detection limit is as low as 0.336 × 10-7 M. Through Gaussian quantization calculation of probe molecules and their reaction products with hydrazine, it is speculated that the recognition mechanism is the closure of intramolecular charge transfer effect. In addition, the cytotoxicity and imaging of HeLa cells were tested, which showed that probes X1-X4 could be used to detect hydrazine in cells.

Cinnamyl Chalcone Based AIE Fluorescent Probes for Sensitive Detection of Hydrazine and its Application in Living Cells.

Widely utilized in the chemical industry and agriculture, hydrazine is easily absorbed by living things and can cause physical harm when in touch for an extended period of time. As a result, a novel cinnamaldehyde chalcone C5 was produced by Friedel Crafts process and aldol condensation reaction. Triphenylamine was used as the raw material for hydrazine determination in both reactions. Chalcone C5 exhibits significant AIE behavior in a mixed mixture of ethanol and water in addition to having great selectivity and a low detection limit (0.119 nm) for hydrazine. The solvent effect test revealed a linear relationship between the Stokes shift of C5 in the solvent and the rise in solvent orientation polarization. It is important to note that C5 is not harmful to MCF-7 cells, mouse kidney cells, or pig kidney cells. Furthermore, research on cell imaging has demonstrated that probe C5 may be utilized to image the fluorescence of hydrazine in active MCF-7 cells.

Aggregation-induced Emission Properties of Triphenylamine Chalcone Compounds.

Two triphenylamine chalcone derivatives 1 and 2 were synthesized through the Vilsmeier-Haack reaction and Claisen-Schmidt condensation reaction. Through ultraviolet absorption spectroscopy and fluorescence emission spectroscopy experiments, it was confirmed that these two compounds exhibited good aggregation-induced emission (AIE) behavior in ethanol/water mixtures. The solvent effect test showed with the increase of the orientation polarizability of the solvent, the Stokes shift in the solvent of compound 1 and compound 2 shows a linear change trend. Through solid state fluorescence test and universal density function theory (DFT), the existence of π-π stacking interaction in the solid state of the compound has been studied, resulting in weak fluorescence emission. pH has no effect on the fluorescence intensity of the aggregate state of excited state intramolecular proton transfer (ESIPT) molecules in an acidic environment, but greatly weakens its fluorescence intensity in an alkaline environment. Cyclic voltammetry (CV) test shows that compound 1 was more prone to oxidation reaction than compound 2. The results of thermal stability test show that the thermal stability of compound 1 was better than that of compound 2, indicating that triphenylamine chalcone derivatives can improve the thermal stability of compounds by increasing the number of branches.

A Novel Fluorescent Probe Based on Pyrazole-Pyrazoline for Fe (III) Ions Recognition.

Firstly, a novel pyrazole-pyrazoline fluorescent probe was developed and synthesized. The probe can be used to determine Fe3+ ions in a series of cations in tetrahydrofuran aqueous solution with high selectivity and high sensitivity. After the addition of iron ions, the fluorescence intensity is significantly reduced, Its structure was characterized by 1H NMR, 13C NMR and HR-ESI-MS. UV absorption spectra and Fluorescence spectroscopy were used to study the selective recognition of probe M on metal ions. The probe M can selectivity and sensitivity to distinguish the target ion from other ions through different fluorescence phenomena. In addition, the binding modes of M with Fe3+ were proved to be 1:1 stoichiometry in the complexes by Job's plot, IR results. The combination of probe M and iron ions is 1:1, and the detection limit is 3.9 × 10-10 M. The binding mode and sensing mechanism of M with Fe3+ was verified by theoretical calculations using Gaussian 09 based on B3LYP/6-31G(d) basis.

A novel coumarin-derived acylhydrazone Schiff base gelator for synthesis of organogels and identification of Fe3.

A novel coumarin-derived acylhydrazone Schiff base fluorescent organogel (G1) was designed and synthesized. Gelator G1 can form stable organogels in isopropanol, tert-amyl alcohol, n-butanol and phenylamine. The organogel could be converted to solution by heating and the solution could be restored to gel state by cooling. The self-assemble mechanism of G1 was investigated by XRD, FT-IR and SEM techniques. The results indicated the intermolecular hydrogen bonding, Van der Waals interaction and π-π stacking are the forces for the self-assembly of the gelator to form the organogel. The optical properties of the compound were studied by UV-visible spectroscopy and fluorescence spectra. Further study presented that gelator G1 could selectively and sensitively response to Fe3+ only among tested cations. Beside the above functions, the organic gel factor G1 could also response to irradiation, heating and shaking, thus endowing the organogel with multi stimulus responsive properties.

Synthesis of nitrogen-doped graphene quantum dots (N-GQDs) from marigold for detection of Fe3+ ion and bioimaging.

Graphene quantum dots (GQDs) are synthesized by the method of high-temperature pyrolysis from marigold granules and subsequently nitrogen-doped graphene quantum dots (N-GQDs) are synthesized from ethylenediamine by hydrothermal treatment, which shows a strong blue emission with 7.84% quantum yield (QY). This will be used in detection of Fe3+ in water environments and the field of bioimaging.

A novel biphenyl-derived salicylhydrazone Schiff base fluorescent probes for identification of Cu2+ and application in living cells.

A novel biphenyl-derived salicylhydrazone Schiff base (BSS) fluorescent probes for highly sensitive and selective identification of Cu2+ has been synthesized. In addition, the recognition has been proved experimentally. The results indicated that the complex forms a 1:1 complex with Cu2+ shows fluorescent quenching. Furthermore, the detection limit of 1.54×10-8M. More interesting, the probe BSS not only have a good biocompatibility in living cells, but also the sense behavior of Cu2+ in the cell nucleus.

A new pyrazoline-based probe of quenched fluorescent reversible recognition for Cu2+ and its application in cells.

A new pyrazoline-based probe D was designed and synthesized, which can be used as a highly sensitive, selective and reversible recognizing fluorescent to detect Cu2+. The recognition properties of this compound was investigated by UV-vis absorption and fluorescence spectrophotometry. The results showed that the probe D forms a 1:1 complex with Cu2+ and displayed a linear fluorescence response to Cu2+ with a detection limit of 1.94×10-7M. In addition, the probe have a good biocompatibility in living cells.