•A triazole-based UiO-66-PSM is synthesized by the CuAAC click reaction.•The triazole unit can act as the metal binding sites to coordinate with Hg2+.•It is capable of detecting Hg2+ in environmental water samples.A novel metal-organic framework (MOF) fluorescent probe UiO-66-PSM is obtained by the copper-catalyzed azide-alkyne click (CuAAC) reaction of UiO-66-N3 with phenylacetylene. The click-generated triazole unit can act as the metal binding site to coordinate with Hg2+, which exhibits the most pronounced fluorescence response (rapid response, excellent selectivity, and high sensitivity) over other metal ions. Moreover, it is capable of detecting Hg2+ in environmental water samples without any structural disintegration of the framework, indicating its high potential in practical applications.A novel metal-organic framework (MOF) UiO-66-PSM is obtained by the copper-catalyzed azide-alkyne click (CuAAC) reaction of UiO-66-N3 with phenylacetylene. This MOF exhibits the high potential in detecting Hg2+ in environmental water samples.Download high-res image (152KB)Download full-size image

A novel fluorescent probe was synthesized and explored to detect cadmium ions (Cd2+) based on an imine functionalized metal–organic framework (MOF). The nanoscale MOF probe (∼100 nm) displayed a turn-on fluorescence in aqueous environments with the addition of Cd2+ which could be ascribed to the interaction between the CN group and specific metal ions, presenting a low-toxicity, highly selective and sensitive detection method for Cd2+ with a detection limit of 0.336 μM (37.8 ppb) and a broad linear range of 0–500 μM, which is promising for application in intracellular sensing and imaging of Cd2+. The probing mechanism was studied and discussed in detail.

A nanoscale cationic porous drug carrier ZJU-101 (ZJU = Zhejiang University), synthesized by the solvothermal method to get the crystal size of ∼300 nm, was used to load diclofenac sodium, an anionic drug. This positively charged host materials showed a large loading capacity of diclofenac sodium (∼0.546 g/g) through ion exchange and penetration procedures. The drug delivery in the inflamed tissues (pH = 5.4) exhibited a more effective release in comparison with that in the normal tissues (pH = 7.4), demonstrating a physiological pH responsive drug release. This discriminating drug release process was controlled by anion exchange between anions in phosphate buttered saline (PBS) and coordinated/free diclofenac anions.

The sensing of hydrogen sulfide (H2S) has become a long-time challenging task. In this work, we developed a general strategy for sensing of H2S utilizing postsynthetic modification of a nano metal–organic frameworks (MOF) UiO-66-(COOH)2 with Eu3+ and Cu2+ ions. The nano MOF Eu3+/Cu2+@UiO-66-(COOH)2 displays the characteristic Eu3+ sharp emissions and the broad ligand-centered (LC) emission simultaneously. Because H2S can strongly increase the fluorescence of Eu3+ and quench the broad LC emission through its superior affinity for Cu2+ ions, the MOF Eu3+/Cu2+@UiO-66-(COOH)2 exhibits highly sensitive turn-on sensing of H2S over other environmentally and biologically relevant species under physiological conditions. Furthermore, this approach for fluorescent turn-on sensing of H2S is expected to extend to other water-stable MOFs containing uncoordinated −COOH.Keywords: fluorescent probes; hydrogen sulfide; metal−organic frameworks; ratiometric sensing; turn-on;

•Pyrromethene dyes doped elastic films as active layers of organic VCSELs.•Mechanically tunable single mode laser emission from 590 to 690 nm.•High slope efficiencies with low laser threshold and wide tuning range.•Under somewhat tough pumping, laser output kept almost unchanged after 1 × 105 pulses.•Fast self-recovery on laser output depending on the dye molecular structure.In this work, various pyrromethene dyes were doped into elastic films of polydimethylsiloxane (PDMS) as active layers of organic VCSELs and the laser properties of such PDMS-based VCSELs were systematically investigated. Mechanically tunable laser emission with high slope efficiencies, low threshold and wide tuning range were obtained. By uploading various stress or changing distributed-Bragg reflector (DBR) mirrors, single mode laser emission could be tuned from ∼590 to 690 nm, indicating their potential applications as cost-effective coherent sources on bio-chips. Under the pump energy 10 times higher than the threshold, the laser emission of organic VCSELs remained at its initial level after 1.2 × 105 pulses and a fast self-recovery process on the laser output energy with the elapse of aging time was observed. The differences between the self-recovery rates of various pyrromethene dyes were also discussed.

A positively charged porous drug carrier MOF-74-Fe(III) (1, MOF = metal–organic framework), which could not be directly synthesized using ferric salts, was prepared through the oxidation of the neutral crystal MOF-74-Fe(II). This cationic host material exhibits very low cytotoxicity upon PC12 cells by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium (MTT) assay and high drug loading capacity of ibuprofen anions (∼15.9 wt %) through ion exchange and salt penetration procedures. Controlled by anion exchange, two mechanisms were involved in the drug release process with different drug delivery rates due to the presence of coordinated or free ibuprofen anions, making the administration of drug release more flexible.

A new fluorescent probe, (E)-3-(3-(4-([2,2′:6′,2′′-terpyridin]-4′-yl)phenyl)acryloyl)-7-(diethylamino)-2H-chromen-2-one (ZC-F4), composed of coumarin as the fluorophore and terpyridine as the receptor was designed and synthesized. This probe showed good selectivity and sensitivity towards Zn2+ even at the ppb level with significant variation of emission wavelength (more than 100 nm shifts) after combination with Zn2+. One can observe that the emission colour changed from green to red. A Job's plot test suggested a 1:1 stoichiometry between ZC-F4 and Zn2+, and the theoretical calculation based on density functional theory has been carried out to gain an insight into the sensing mechanism. Furthermore, imaging of Zn2+ in cells was also performed to test its feasibility in biology. This fluorescence probe should be a promising candidate for applications in cell-imaging, environment protection, water treatment and safety inspection.

•A new fluorescent and colorimetric probe with strong ICT effect.•Significant fluorescence enhancement and changes in color toward hydrazine.•High sensitivity at ppb level with a detection limit lower than that regulated by EPA.•Wide range detection resulted from large conjugated system.A new fluorescent and colorimetric probe based on the reaction and intramolecular charge transfer (ICT) effect is designed and synthesized. The probe responds rapidly toward hydrazine and exhibits distinct color changes from yellow to colorless, indicating its use as a color indicator for hydrazine. Moreover, the probe also shows a significant broad band fluorescence (410–700 nm) enhancement by ∼120-fold after the addition of hydrazine. With a detection limit as low as 0.11 ppb, the probe can detect hydrazine in a wide concentration range because of the blunted sensing functional group. The contrast test shows almost no interruption from common elements in water, suggesting the high selectivity of this probe toward hydrazine. The theoretical calculation based on density functional theory (DFT) is also performed and two different ICT modes are found. This hydrazine probe would be a promising candidate applicable in environment protection, water treatment and safety inspection.

A new fluorescence probe for distinguishing Zn2+ and Cd2+ is designed and synthesized. For the first time to our knowledge, this probe can recognize similar metal ions by coherently utilizing intramolecular charge transfer (ICT) and different electronic affinities of various metal ions, instead of by selective coordination alone, which may be interfered with and lose its selectivity easily in a complicated environment, providing a distinct recognition even by the naked eye for Zn2+ and Cd2+ with the sensitivity at the ppb level. This design strategy may initiate a straightforward approach for the selective detection of various metal ions with similar chemical properties in extensive applications such as environmental, industrial, and bio-science.

Three novel organic dyes containing 2,6-dicarbonyl-pyridine as the central electron acceptor with different end-caped amino groups as donors in the D-π-A-π-D arrangement are designed and synthesized. All three molecules exhibit large TPA cross-sections (δ > 1000 GM). The cooperative effects of donor strength, conjugation length and solvent polarity on the TPA activity are studied. The conjugated system plays an important role on the enhancement of δ in the highly polar solvent, while donor strength has more impact on TPA properties. The influence of the solvent polarity on TPA properties is studied by two-photon excited fluorescence (TPEF) measurement. The result shows a nonmonotonic relationship between the TPA cross-section and the solvent, and the maximum of δ is found in solvents with moderate polarity. The δ of molecules with stronger donor reaches the maximum in more polar solvents. The highest δ is found to be 5250 GM in CHCl3. All compounds exhibit large Stokes shifts due to the strong intramolecular charge transfer (ICT) effect.Highlights► Large TPA cross-section was obtained on three small molecules. ► Strengthened acceptor consisting two strong electron-withdrawing groups. ► Nonmonotonic but regular TPA response towards the variation of solvent polarity. ► Red emission was observed in one of the three molecules.

•Miniaturized organic photodiodes fabricated by a piezoelectric inkjet method.•Spectral-resolving capability resulted from the J-aggregate formed during droplet drying.•J-aggregate formation is improved at the lower dye concentration.•Sensitivity of the photodiode is improved by 3 orders of magnitude at optimized dye concentration.•Inkjet printed spots can be stacked without deteriorating the J-aggregate formation.In this work, wavelength sensitive organic bulk-hetero photodiodes were fabricated by a piezoelectric inkjet method based on the J-type aggregates of cyanine dye molecules doped into poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) thin films on indium tin oxide anodes. The cyanine dye concentration in the inkjet printed films was optimized and the J-aggregate formation during the drying process was investigated by local absorption spectra. It was found that at lower dye concentrations, not only the J-aggregate formation but also the radiation sensitivities of the films were improved significantly. Moreover, the stacking of the cyanine dye – poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) spots demonstrated the linear increase on the optical density and film thickness without deteriorating the J-aggregate formation, indicating their potential in application as narrow band filters.

A BA-derived fluorescent pH sensor for use under strongly acidic conditions based on the ICT effect was realized to exhibit high stability, sensitivity and selectivity. This probe can be used to detect acidity within the pH range 0.5–2.5. The design strategy may help to develop probes for targets at high concentrations.

•A new chemosensor based on the ortho-methylation of boron-dipyrromethene.•Fluorescent “turn-on” detection for HTM ions with high sensitivity and selectivity.•The detection upper limit for Ag+ is as low as 1.2 ppm.•The ortho-methyl group enhances the quantum efficiency and detection sensitivity.A fluorescent chemosensor, ortho-methylated boron-dipyrromethene (o-MBDP) has been synthesized and characterized. It featured excellent selectivity and sensitivity for Ag+ and Hg2+ ions, which could enhance the weak fluorescence of o-MBDP drastically by several hundred times through coordination and as a result, behave as an efficient “turn-on” fluorescent probe. The detection upper limit for Ag+ ion could be decreased by at least one order of magnitude with the introduction of the ortho-methyl group, in comparison with analogous boron-dipyrromethene (BDP) sensors, indicating the feasibility in extensive application areas as chemosensors.

In this work, the laser dye PM567 was incorporated into various organically modified silicate gel glasses (ORMOSILs) derived by methyltriethoxysilane (MTES) and vinyltriethoxysilane (VTES) precursors mixed in various ratios. The laser performances of PM567 doped into MTES–VTES-derived ORMOSILs including the laser slope efficiency, threshold and lifetime together with the spectroscopic properties were investigated. Blue-shifts of fluorescent peaks, extended fluorescent lifetime, improved laser efficiency and lifetime of PM567 doped into ORMOSILs derived by mixed precursors of MTES and VTES have been observed, which might related to the microstructures and micro-chemical environment of the dye in ORMOSILs.

A new fluorescence probe for distinguishing Zn2+ and Cd2+ is designed and synthesized. For the first time to our knowledge, this probe can recognize similar metal ions by coherently utilizing intramolecular charge transfer (ICT) and different electronic affinities of various metal ions, instead of by selective coordination alone, which may be interfered with and lose its selectivity easily in a complicated environment, providing a distinct recognition even by the naked eye for Zn2+ and Cd2+ with the sensitivity at the ppb level. This design strategy may initiate a straightforward approach for the selective detection of various metal ions with similar chemical properties in extensive applications such as environmental, industrial, and bio-science.

A new fluorescent probe, (E)-3-(3-(4-([2,2′:6′,2′′-terpyridin]-4′-yl)phenyl)acryloyl)-7-(diethylamino)-2H-chromen-2-one (ZC-F4), composed of coumarin as the fluorophore and terpyridine as the receptor was designed and synthesized. This probe showed good selectivity and sensitivity towards Zn2+ even at the ppb level with significant variation of emission wavelength (more than 100 nm shifts) after combination with Zn2+. One can observe that the emission colour changed from green to red. A Job's plot test suggested a 1:1 stoichiometry between ZC-F4 and Zn2+, and the theoretical calculation based on density functional theory has been carried out to gain an insight into the sensing mechanism. Furthermore, imaging of Zn2+ in cells was also performed to test its feasibility in biology. This fluorescence probe should be a promising candidate for applications in cell-imaging, environment protection, water treatment and safety inspection.