Deep eutectic solvents (DESs), a new type of green solvents, were applied for the extraction of proteins with aqueous biphasic systems (ABSs) in this study. The structures of the prepared DES were confirmed by FT-IR and 1H NMR. The DES–salt (NaH2PO4/Na2CO3/Na3C6H5O7)-based ABSs were established and applied to extract the bovine serum albumin and papain. DES–Na2CO3 ABS was selected as the suitable extraction system. Single-factor experiments were investigated to achieve complete extraction by properly tailoring the concentration of different compositions (e.g. proteins, Na2CO3, DES), the temperature and pH values. The experimental results indicated that the extraction efficiency could reach up to 95.16% for bovine serum albumin and 90.95% for papain under the optimum conditions. UV-vis spectra, fluorescence spectra and CD spectra were investigated to confirm that the conformation of bovine serum albumin did not change after extraction. The transmission electron microscopy (TEM) was used to explore the mechanism of the extraction. All of these results indicated that DES-based ABSs may provide a new possibility for the separation of proteins.

•Gd-DTPA-FITC-CS11 has higher binding affinity to BSA.•Gd-DTPA-FITC-CS11 exhibited higher in vitro properties than commercial Gd-DTPA.•Gd-DTPA-FITC-CS11 was a promising dual-modal imaging contrast agent.The fusion of molecular and anatomical modalities facilitates more reliable and accurate detection in clinic. In this work, we prepared gadolinium (III) complex Gd-DTPA-FITC-CS11 with magnetic resonance (MR) and fluorescence dual-modal imaging modalities. Gd-DTPA-FITC-CS11 consisted of fluorescein isothiocyanate and low-molecular-weight chitosan (CS11) units conjugated with gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA). Gd-DTPA-FITC-CS11 exhibited a higher longitudinal relaxivity (14.09 mM−1 s−1) than the clinical Gd-DTPA (3.85 mM−1 s−1). T1-weighted MR contrast enhancement was also demonstrated the comparability to Gd-DTPA at lower dosage. The binding with bovine serum albumin (BSA) was investigated. The fluorescence of BSA in the presence of Gd-DTPA-FITC-CS11 was weakened due to static quenching mechanism. The conformation of BSA was slightly changed but α-helix was dominant. The binding was entropy-driven and spontaneous and the main contribution was hydrophobic interaction. Our results suggested the potential of Gd-DTPA-FITC-CS11 as an MR/fluorescence dual-modal imaging contrast agent in improving the diagnostic sensitivity and accuracy.

A series of hybrid materials tungsten-containing meso-ceria characterized in detail have been designed from polyoxometalates-based ionic liquids using a one-pot hydrothermal and calcination method for heterogenous oxidative desulfurization. The experimental results indicated that the as-prepared catalysts possessed mesoporous structures and the tungsten species were well dispersed in the ceria. The effect of calcination temperature and tungsten content on the hybrid materials during the removal of dibenzothiophene was also investigated. Based on the experimental results, the optimal molar ratio of tungsten/ceria and calcination temperature of the hybrid materials were 0.25 and 400 °C, respectively, wherein the catalytic performance could reach 99.2% under mild conditions. It is also found that the catalyst could remove other sulfur-containing compounds in the order of DBT > BT > 4,6-DMDBT.

•Solvent-controlled difluoromethylation of 2′-hydroxychalcones is developed.•The difluoromethyl ethers are obtained with 47–97% yields in p-xylene.•The difluorinated cyclic ethers are obtained with 21–75% yields in acetonitrile.•Difluorocarbene forms two chemical bonds between phenol O and carbonyl C.The solvent-controlled difluoromethylation of 2′-hydroxychalcones using the shelf-stable reagent difluoromethylene phosphabetaine for divergent synthesis of 2′-difluoromethoxychalcones and 2,2-difluoro-3-styryl-2,3-dihydrobenzofuran-3-ols is developed. When difluoromethylation was performed in p-xylene, 2′-difluoromethoxychalcones were the major product with 47–97% yields, while 2,2-difluoro-3-styryl-2,3-dihydrobenzofuran-3-ols were obtained in 21–75% yields using acetonitrile as solvent. A plausible reaction mechanism was proposed according to the experimental results.The solvent-controlled difluoromethylation of 2′-hydroxychalcones using the shelf-stable reagent difluoromethylene phosphabetaine for divergent synthesis of 2′-difluoromethoxychalcones and 2,2-difluoro-3-styryl-2,3-dihydrobenzofuran-3-ols is developed. When difluoromethylation was performed in p-xylene, 2′-difluoromethoxychalcones were the major product with 47–97% yields, while 2,2-difluoro-3-styryl-2,3-dihydrobenzofuran-3-ols were obtained in 21–75% yields using acetonitrile as solvent.

•A simple and sensitive PEC strategy based on the Au/BiOCl composites is designed for 4-chlorophenol detection.•The Au/BiOCl composites have been prepared in the [C16mim]Cl by a facile one-pot solvothermal reaction.•The PEC detection method shows wide detectable range and low detection limit.The Au/BiOCl composites have been prepared by a facile one-pot ethylene glycol (EG) assisted solvothermal reaction in the presence of ionic liquid 1-hexadecyl-3-methylimidazolium chloride ([C16mim]Cl). During the synthesis procedure, the [C16mim]Cl has been used as Cl source, solvent of this system, and dispersing agent to effectively disperse Au on the surface of BiOCl. The as-prepared samples have been systematically characterized by multiple instruments to investigate the structure, morphology, and photoelectrochemical properties. According to the photoelectrochemical data, the Au/BiOCl composites exhibit better photoelectrochemical performance toward the detection of 4-chlorophenol than that of the pure BiOCl. The photocurrent response of Au/BiOCl modified electrode is high and stable under light irradiation. The proposed Au/BiOCl modified electrode shows a wide linear response ranging from 0.16 to 20 mg L−1 with detection limit of 0.05 mg L−1. It indicates a dramatically promising application of bismuth oxyhalides in photoelectrochemical detection. It will be expected that the present study may be lightly extended to the monitor of other organic pollutants by photoelectrochemical detection of the Au/BiOCl composites.

•The calculated spectra agree well with the experimental results. Experimental characteristic peaks have been assigned.•Redshifts were observed and the formation of hydrogen bonds mainly contributes to the redshifts.•Both of the B3LYP and B3LYP-D3 are excellent to reproduce the experimental results.•The hydrogen bonds were proved to exist in DESs between the HBD and HBA by structure analysis and RDG analysis.Deep eutectic solvents (DESs), as ionic liquid analogues for green solvents, have gained increasing attentions in chemistry. In this work, three typical kinds of DESs (ChCl/Gly, ChCl/AcOH and ChCl/Urea) were successfully synthesized and characterized by Fourier transform infrared spectroscopy (FTIR) and Raman. Then comprehensive and systematical analyses were performed by the methods of density functional theory (DFT). Two methods (B3LYP/6-311 + +G(2d,p) and dispersion-corrected B3LYP-D3/6-311 + +G(2d,p)) were employed to investigate the structures, vibrational frequencies and assign their ownership of vibrational modes for the DESs, respectively. Nearly all the experimental characteristic peaks of IR and Raman were identified according to the calculated results. By linear fitting of the combined calculated vs experimental vibration frequencies, it can be found that both of the two methods are excellent to reproduce the experimental results. Besides, hydrogen bonds were proved to exist in DESs by IR spectrum, structure analysis and RDG analysis. This work was aimed at predicting and understanding the vibrational spectra of the three typical DESs based on DFT methods. Moreover, by comparing experimental and theoretical results, it provides us a deep understanding of the formation mechanisms of DESs.A bridge connecting experiment and calculation for deep eutectic solvents (DESs) has been built by density functional theory. The infrared and Raman spectra have been calculated to compare with experiment. Almost all the experimental characteristic peaks can be assigned according to computational results. Structure analysis and reduced density gradient analysis (RDG) have been carried out to deep understand the interactions in deep eutectic solvents.

•BiPO4 photocatalyst have been synthesized in the presence of ionic liquids [Omim]H2PO4.•Ionic liquid played the role of solvent, reactant and template at the same time.•The different photocatalytic activities of BiPO4 samples is mainly attributed to the different morphologies and microstructures.Bismuth phosphate (BiPO4) has been researched as one of the important bismuth-containing salts with high-efficient photocatalytic activity under UV light irradiation. However, the morphologies and microstructures of BiPO4 photocatalyst on photocatalytic activity have not been clearly investigated. Herein, BiPO4 photocatalyst with various morphologies and microstructures have been synthesized via a facile reactable ionic liquid [Omim]H2PO4 assisted solvothermal process in H2O, ethanol, ethylene glycol (EG) and ethylene glycol monomethyl ether (EGME), respectively. The photocatalytic ability of the as-prepared samples was evaluated using ciprofloxacin (CIP) as target pollutant. The result implied that different photocatalytic activities for CIP degradation is mainly attributed to different morphologies and microstructures of BiPO4 samples prepared in different solvents. The BiPO4 sample which was prepared under H2O condition showed the highest photocatalytic activity. In addition, inorganic salt NaH2PO4·2H2O was utilized to prepare BiPO4 samples instead of [Omim]H2PO4. It can be found that the photocatalytic efficiency of BiPO4 prepared via ionic liquid exhibited higher photocatalytic activity than that of inorganic salt for the degradation of CIP under UV light irradiation.

•CS8PA-GLA was characterized with FTIR, SEM, TG/DSC, XRD and BET.•Cd(II) was removed.•The sorption mechanism was chelation.A 23 factorial design was used to examine the sorption of Cd2+ onto cross-linked low molecular weight chitosan pyruvic acid derivative. Three factors and two levels of solution pH (A) (6.0 or 10.0), temperature (B) (45 or 70 °C) and Cd(II) concentration (C) (1 or 3 mg/L) were considered. Batch mode system was employed with 0.05 g of the sorbent and 25 mL of Cd(II) solution. The efficiency of cadmium removal during an exposition time of 4 h was then evaluated. The factors and their interaction effect on the cadmium removal efficiency followed the order: Cd(II) concentration > solution pH > interaction between solution pH and Cd(II) concentration > interaction between solution pH, temperature and Cd(II) concentration. Langmuir isotherm model was the best isotherm model. The Pseudo second order fitted well the kinetic data. The thermodynamic studies revealed the nature of the cadmium sorption.

Difluoromethylation of 2-hydroxychalcones using sodium 2-chloro-2,2-difluoroacetate as the difluoromethylating agent was developed. Under facile conditions, a wide range of aryl difluoromethyl ethers were obtained in yields of 36%–80%. It is noteworthy that the new addition products, 2,2-difluoro-2H-benzofuran derivatives, were also synthesized in the reactions. The yield of 2,2-difluoro-2H-benzofuran derivative could be up to 35% when 3-methyl-2-hydroxychalcone was used as the reactant. A plausible reaction mechanism was proposed.

Due to their unprecedented electronic, surface and optical properties, the atomic-thick graphene-like materials have aroused great interest. Compared with the bulk counterparts, the graphene-like material can not only enhance the internal properties, but also gives rise to new promising properties. Herein, the graphene-like carbon nitride (graphene-like C3N4) was synthesized via liquid exfoliation from the bulk graphitic carbon nitride (g-C3N4) in 1,3-butanediol (1,3-BUT) for the first time. And the graphene-like C3N4 was characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), transmission electron microscopy (TEM), thermogravimetric analysis (TG), and X-ray photoelectron spectroscopy (XPS). The obtained graphene-like C3N4 exhibited a two-dimensional thin-layer structure with about 3–6 atoms thickness, a high specific surface area of 32.54 m2 g−1, increased photocurrent responses, improved electron transport ability and enhanced photocatalytic activity. The photocatalytic reaction for the organic dye methylene blue (MB) by the graphene-like C3N4 followed first-order kinetics. Moreover, the graphene-like C3N4 exhibited a higher apparent rate of 0.1262 min−1, which was 3.1 times higher than that of the bulk g-C3N4 (0.0409 min−1). The enhanced photocatalytic reaction was due to a high specific surface area and a larger bandgap (by 0.14 eV). The yield of the graphene-like C3N4 was up to ∼0.35 mg mL−1. Moreover, the graphene-like C3N4 had a new property that it could be used as the sensor for trace amounts of Cu2+ determination, so the graphene-like C3N4 is a new but promising candidate for heavy metal ions (Cu2+) determination in water environment. Photoelectrochemical selective sensing of trace amounts of Cu2+ was also discussed.

•The GO/Ag2CO3 composite based on GO was prepared by a facile one-step synthesis.•The photocatalytic degradation followed the pseudo-first-order reaction model.•GO promoted the separation of photoexcited electron–hole pairs in the GO/Ag2CO3.Ag2CO3 coupled with graphene-oxide composites were prepared by a facile one-step synthesis. The samples were characterized by Scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), Fourier transformed infrared (FT-IR) spectroscopy and Raman spectra. The as-prepared graphene-oxide/Ag2CO3 (GO/Ag2CO3) exhibited universally high photocatalytic activity toward typical methylene blue (MB) and methyl orange (MO) in aqueous solution. A possible photocatalytic mechanism was investigated by a series of radical trapping experiment. The kinetics of the GO/Ag2CO3 composites were also proposed. The result showed that GO might serve as an electron collector and a transporter to promote the separation of photoexcited electron–hole pairs and to decrease the possibility of electron and hole recombination efficiently. This work has set up a simple method for exploring the excellent GO-based photocatalysts.

Mn-TCPP-CSn(n=6, 11, 20) as a type of potential magnetic resonance imaging(MRI) contrast agents were synthesized via manganese(II) meso-tetra(4-carboxyphenyl) porphyrin(Mn-TCPP) modified with chitosan oligosaccharides(CSn). Experimental data of infared(IR), UV-Vis, MS, inductively coupled plasma-atomic emission spectrometer(ICP-AES) and size exclusion chromatography evidenced the formation of Mn-TCPP-CSn. The stability results show that Mn-TCPP-CSn in aqueous solution was stable enough to prevent Mn(II) ions from leaking. The magnetic properties in vitro indicate that Mn-TCPP-CS20 possesses higher longitudinal relaxivity(r1=10.38 L·mmol−1·s−1) in aqueous solution than unmodified porphyrin Mn-TCPPNa4[manganese(II) meso-tetra(4-carboxyphenyl) porphyrin, tetrasodium salt](r1=5.10 L·mmol−1·s−1) and the commercial contrast agent Gd-DTPA(r1=4.05 L·mmol−1·s−1). The preliminary T1-weighted flash image studies in vitro show that the contrast and the imaging signal of Mn-TCPP-CSn were superior to those of Mn-TCPPNa4 and Gd-DTPA under the same conditions. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) assay shows that Mn-TCPP-CSn has a good biocompatibility. In addition, the thermodynamical parameters(ΔH<0, ΔS<0, ΔG<0) of Mn-TCPP-CSn bound to bovine serum albumin(BSA) show that Mn-TCPP-CSn could bind to BSA spontaneously, where the binding complex was stabilized mainly by van der Waals interactions and hydrogen bonds. These results suggest that Mn-TCPP-CSn have the advantage of becoming a potential MRI contrast agent.

This study was to describe the synthesis of complexes of gadolinium diethylenetriaminepentaacetic acid conjugates of low-molecular-weight chitosan oligosaccharide Gd-DTPA-CSn (n = 6, 8, 11) as a new class of contrast agent as well as its magnetic property in a pilot magnetic resonance imaging. The efficacy of the contrast agent was assessed by measuring the longitudinal relaxivity (r1), FLASH imaging in phantoms in vitro and signal intensity in vivo of the rat abdominal axial imaging. The r1 of Gd-DTPA-CS11 was up to 11.65 mM− 1·s− 1, which was 3 times higher than that of the analogous MRI contrast agent Gd-DTPA in commercial use. In vivo MR images of rat obtained with Gd-DTPA-CS11 showed strong signal enhancement in liver and the vessels of the liver parenchyma during the extended period of time. The present study suggests that the new synthesized gadolinium complexes can be used as a new class of practical liver-specific MRI contrast agent because of its superior performance compared with Gd-DTPA.

A new gadolinium diethylenetriamine pentaacetic acid (DTPA) complex (Gd-DTPA-DMABA-CS11) as a potential bimodal magnetic resonance imaging (MRI) contrast agent with fluorescence was synthesized. It was synthesized by the incorporation of 4-dimethylaminobenzaldehyde (DMABA) and chitosan oligosaccharide (CSn; n = 11) with low polydispersity index to DTPA anhydride and then chelated with gadolinium chloride. The structure was characterized by Fourier transform infrared (FTIR), 1H NMR, elemental analysis and size exclusion chromatography (SEC). MRI measurements in vitro were evaluated. The results indicated that Gd-DTPA-DMABA-CS11 provided higher molar longitudinal relaxivity (r1) (12.95 mM− 1 · s− 1) than that of commercial Gd-DTPA (3.63 mM− 1 · s− 1) at 0.5 T. Gd-DTPA-DMABA-CS11 also emitted fluorescence, and the intensity was much stronger than that of Gd-DTPA. Therefore, it can be meanwhile used in fluorescent imaging for improving the sensitivity in clinic diagnosis. Gd-DTPA-DMABA-CS11 as a potential contrast agent is preliminarily stable in vitro. The results of thermodynamic action between Gd-DTPA-DMABA-CS11 and bovine serum albumin (BSA) illustrated that the binding process was exothermic and spontaneous, and the main force was van der Waals’ interaction and hydrogen bond. The preliminary study suggested that Gd-DTPA-DMABA-CS11 could be used in both magnetic resonance and fluorescent imaging as a promising bimodal contrast agent.

Due to their unprecedented electronic, surface and optical properties, the atomic-thick graphene-like materials have aroused great interest. Compared with the bulk counterparts, the graphene-like material can not only enhance the internal properties, but also gives rise to new promising properties. Herein, the graphene-like carbon nitride (graphene-like C3N4) was synthesized via liquid exfoliation from the bulk graphitic carbon nitride (g-C3N4) in 1,3-butanediol (1,3-BUT) for the first time. And the graphene-like C3N4 was characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), transmission electron microscopy (TEM), thermogravimetric analysis (TG), and X-ray photoelectron spectroscopy (XPS). The obtained graphene-like C3N4 exhibited a two-dimensional thin-layer structure with about 3–6 atoms thickness, a high specific surface area of 32.54 m2 g−1, increased photocurrent responses, improved electron transport ability and enhanced photocatalytic activity. The photocatalytic reaction for the organic dye methylene blue (MB) by the graphene-like C3N4 followed first-order kinetics. Moreover, the graphene-like C3N4 exhibited a higher apparent rate of 0.1262 min−1, which was 3.1 times higher than that of the bulk g-C3N4 (0.0409 min−1). The enhanced photocatalytic reaction was due to a high specific surface area and a larger bandgap (by 0.14 eV). The yield of the graphene-like C3N4 was up to ∼0.35 mg mL−1. Moreover, the graphene-like C3N4 had a new property that it could be used as the sensor for trace amounts of Cu2+ determination, so the graphene-like C3N4 is a new but promising candidate for heavy metal ions (Cu2+) determination in water environment. Photoelectrochemical selective sensing of trace amounts of Cu2+ was also discussed.