Guangyou Zhang

An efficient metal- and solvent-free organocatalytic system for chemical fixation of CO2 into cyclic carbonates under mild conditions

An efficient, metal- and solvent-free catalytic system was developed for the conversion of CO2 and epoxides to the corresponding cyclic carbonates under mild conditions (T = 25–45 °C, 1 atm CO2) in high-to-excellent yields. The catalyst could be easily recycled, providing a more sustainable process for the chemical fixation of CO2.

Facile strategy for fabrication of transparent superhydrophobic coatings on the surface of paper

A one-step dip coating process was applied to fabricate a transparent superhydrophobic coating on the surface of paper using silica nanoparticles modified with long-chain hydrocarbon hexadecyltrimethoxysilane in an ethanolic solution.

A differentially selective probe based on diketopyrrolopyrrole with fluorescence turn-on response to Fe3+, and dual-mode turn-on and ratiometric response to Au3+, and its application in living cell imaging

A diketopyrrolopyrrole-based probe DPP-PyR was able to recognize Fe(3+) and Au(3+) with fluorescent turn-on response via different emission modes with relatively low detection limit. Moreover, DPP-PyR exhibited preferential second mode of selectivity for Au(3+) as it ratiometrically displaced Fe(3+) from the [DPP-PyR+Fe(3+)] complex. Furthermore, the imaging experiments indicated that this probe was cell-permeable and could be used to detect Fe(3+) and Au(3+) ions within living cell. To the best of our knowledge, it was the first probe for detection Fe(3+) and Au (3+) at the same time ever reported.

A new diketopyrrolopyrrole-based probe for sensitive and selective detection of sulfite in aqueous solution

A new probe was synthesized by incorporating an α,β-unsaturated ketone to a diketopyrrolopyrrole fluorophore. The probe had exhibited a selective and sensitive response to the sulfite against other thirteen anions and biothiols (Cys, Hcy and GSH), through the nucleophilic addition of sulfite to the alkene of probe with the detection limit of 0.1 μM in HEPES (10 mM, pH 7.4) THF/H2O (1:1, v/v). Meanwhile, it could be easily observed that the probe for sulfite changed from pink to colorless by the naked eye, and from pink to blue under UV lamp after the sulfite was added for 20 min. The NMR and Mass spectral analysis demonstrated the expected addition of sulfite to the C=C bonds.

Novel fluorescent sensors based on benzimidazo[2,1-a]benz[de]isoquinoline-7-one-12-carboxylic acid for Cu2+

Fluorescent sensors of N-(4-methylpiperazin-1-yl)benzimidazo[2,1-a]benz[de]isoquinoline-7-one-12-carboxylamide (C1) and its corresponding quaternary ammonium salt (C2) were prepared. C1 showed 45-fold fluorescence turn-on response towards Cu2+ with a detection limit of 5.7 × 10−8 mol L−1 in acetonitrile–H2O (9:1) buffer solution and C2 showed 18-fold fluorescence enhancement towards Cu2+ with a detection limit of 3.4 × 10−7 mol L−1 in the same condition. The Cu2+ sensing of C1 and C2 were both based on the photoinduced electron transfer (PET) process. Such behaviors confirmed that the benzimidazo[2,1-a]benz[de]isoquinoline-7-one-12-carboxylic acid based C1 and C2 could be utilized as fluorescent sensors for Cu2+. The mechanism of fluorescence enhancement of C1 towards Cu2+ was verified by DFT/TDDFT calculation using Gaussian 03. In addition, an obvious color change was observed when an aqueous solution of C2 was treated with aqueous NaOH. Such behavior confirms that C2 could be used as a fluorescent OH− sensor in water.

Simple, robust and large-scale fabrication of superhydrophobic surfaces based on silica/polymer composites

Superhydrophobic surfaces were facilely fabricated by a brush coating process based on silica/polymer composites. The hydrophobicity of the obtained surfaces can be tuned by varying the weight ratio of silica/polymer. The simple and robust strategy can facilitate the fabrication of superhydrophobic surfaces in large-scale on general substrates.

Colorimetric and fluorogenic signalling of fluoride ions by diketopyrrolopyrrole-based chemosensor

A new colorimetric and on–off fluorescence sensor based on diketopyrrolopyrrole (DPP) was synthesized for detection of fluoride anion. The sensor displayed a rapid responsivity and high selectivity and sensitivity towards F− over other anions, and it also exhibited a very low detection limit of 4.07 × 10−8 M. The signaling process was confirmed by UV-vis, fluorescence measurements as well as 1H and 19F NMR spectroscopy. The experimental results revealed that the formation of anionic species from deprotonation of the hydrazone N–H moiety by fluoride ion was responsible for the spectral changes. Density function theory calculations were conducted to rationalize the optical response of the sensor.

A novel polythiophene derivative as a sensitive colorimetric and fluorescent sensor for anionic surfactants in water

A novel cationic polythiophene derivative, poly[N,N,N-trimethyl-4-(thiophen-3-ylmethylene)cyclohexanaminium chloride] (PTCA-Cl), has been prepared successfully and applied as a colorimetric and fluorometric probe for the detection of anionic surfactants. In particular, a new method for the polymerization of cationic polythiophene derivatives is found, which has not been reported previously. The colorimetric and fluorescent response of PTCA-Cl to anionic surfactants have been investigated by absorption and emission spectroscopy. The sensing interaction can be apparently observed by the naked eye, which presents a great advantage for its practical applications. Moreover, the sensor (PTCA-Cl) shows high selectivity towards anionic surfactants in the presence of other negatively charged analytes, as well as high sensitivity with a detection limit at 10−9 M by using fluorimetry, which is the lowest ever achieved among all synthetic anionic surfactants sensors available. Therefore, the water soluble polythiophene derivative can be applied as a colorimetric and fluorescent probe for the detection of anionic surfactants with high selectivity and sensitivity.

A ratiometric fluorescent probe for quantification of alkaline phosphatase in living cells

A ratiometric fluorescent probe with strong intramolecular charge transfer (ICT) character has been designed for the detection of alkaline phosphatase (ALP). In the presence of ALP, probe 1 showed a dramatic bathochromic shift from 550 to 650 nm in the fluorescence spectrum and an obvious ratiometric signal with an isoemissive point was observed. The spectral change was attributed to the hydrolysis and cleavage of a phosphate group from the probe that changed the ability of the intramolecular charge transfer. The fluorescence intensity ratio displayed a linear relationship against the concentration of ALP in the concentration range from 50 to 200 U L−1. Other biological species, including lysozyme, trypsin, pepsin, acetyl cholinesterase, carboxylesterase, and bovine serum albumin, did not induce distinct spectral changes of the probe, indicating its selective sensing ability to ALP. Furthermore, probe 1 was also successfully applied to image endogenous ALP activity in living cells.

A fluorescence chemosensor based on imidazo[1,2-a]quinoline for Al3+ and Zn2+ in respective solutions

A new chemosensor, N′-[(2-hydroxyphenyl)methylidene]imidazo[1,2-a]quinoline-2-carbohydrazide (L2), was developed, which could detect Al3+ in DMSO/H2O HEPES buffer and Zn2+ in EtOH/H2O HEPES buffer. The chemosensor exhibits high selectivity and sensitivity for sensing Al3+ and Zn2+ with a fluorescence “turn-on” mode.