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2015 Volume 74 Issue 2
2015, 74(2): 113-129
doi: 10.6023/A15080547
Abstract:
Emerging as a relatively new class of porous materials, metal-organic frameworks (MOFs), possessing diversified, designable and tailorable structures as well as ultrahigh surface area, have captured broad research interest and shown potential applications in many fields in recent years. In particular, MOFs have attracted intensive attention in catalysis. In the first two parts of this review, according to the origin of active sites, for examples, coordinatively unsaturated metal centers, functional organic linkers, functional sites chemically grafted onto the framework, as well as metal complexes or metal nanoparticles (MNPs) encapsulated inside the MOFs, etc., we have summarized the recent progress in heterogeneous catalysis over MOFs and their composites in recent several years. In addition, the MOF-based photocatalysis and electrocatalysis have also been briefly introduced in the subsequent two parts. Finally, the further development and challenge in MOF catalysis are discussed.
Emerging as a relatively new class of porous materials, metal-organic frameworks (MOFs), possessing diversified, designable and tailorable structures as well as ultrahigh surface area, have captured broad research interest and shown potential applications in many fields in recent years. In particular, MOFs have attracted intensive attention in catalysis. In the first two parts of this review, according to the origin of active sites, for examples, coordinatively unsaturated metal centers, functional organic linkers, functional sites chemically grafted onto the framework, as well as metal complexes or metal nanoparticles (MNPs) encapsulated inside the MOFs, etc., we have summarized the recent progress in heterogeneous catalysis over MOFs and their composites in recent several years. In addition, the MOF-based photocatalysis and electrocatalysis have also been briefly introduced in the subsequent two parts. Finally, the further development and challenge in MOF catalysis are discussed.
2015, 74(2): 130-148
doi: 10.6023/A15090617
Abstract:
In the mid 1990s, Lu and co-workers reported the nucleophilic phosphine-triggered annulation reactions of allenoates with electron-deficient olefins or imines. As one of the most efficient and straightforward synthetic strategies for the construction of highly functionalized carbocycle or heterocycle structural motifs, the development and application of nucleophilic phosphine-triggered annulation of allenoates by using various nucleophilic phosphines and electron-deficient partners have attracted more and more interests of chemists over the past decades. Furthermore, the development of asymmetric phosphine-triggered annulation of allenoates cleaved a new way to the total synthesis of bioactive natural products and medicinally important substances. In addition, aldehydes and ketones were also employed into this reaction, leading to a wide range of O-fused heterocycles. This review focuses on the important developments concerning racemic and asymmetric annulation reactions of allenoates in the past two decades.
In the mid 1990s, Lu and co-workers reported the nucleophilic phosphine-triggered annulation reactions of allenoates with electron-deficient olefins or imines. As one of the most efficient and straightforward synthetic strategies for the construction of highly functionalized carbocycle or heterocycle structural motifs, the development and application of nucleophilic phosphine-triggered annulation of allenoates by using various nucleophilic phosphines and electron-deficient partners have attracted more and more interests of chemists over the past decades. Furthermore, the development of asymmetric phosphine-triggered annulation of allenoates cleaved a new way to the total synthesis of bioactive natural products and medicinally important substances. In addition, aldehydes and ketones were also employed into this reaction, leading to a wide range of O-fused heterocycles. This review focuses on the important developments concerning racemic and asymmetric annulation reactions of allenoates in the past two decades.
2015, 74(2): 149-154
doi: 10.6023/A15090584
Abstract:
Glycoproteins play very important roles in many biological processes. The separation and enrichment of glycoproteins/glycopeptides is still considered a challenging task because of the low abundance and microheterogenity. This review introduces the chemistry method of separation and enrichment of glycoproteins and glycopeptides:hydrozide chemistry, amine chemistry, boronic acid chemistry, beta-elimination and Michael addition chemistry.
Glycoproteins play very important roles in many biological processes. The separation and enrichment of glycoproteins/glycopeptides is still considered a challenging task because of the low abundance and microheterogenity. This review introduces the chemistry method of separation and enrichment of glycoproteins and glycopeptides:hydrozide chemistry, amine chemistry, boronic acid chemistry, beta-elimination and Michael addition chemistry.
2015, 74(2): 155-164
doi: 10.6023/A15090597
Abstract:
Protein tyrosine phosphatase 1B (PTP1B) is an enzyme that downregulates the insulin receptor. It has been considered as one of the drug targets of diabetes, and the inhibitors for PTP1B to treat type II diabetes have received considerable attention. The study reports a discovery of a new lead compound inhibiting PTP1B. In this work, PTP1B protein was expressed, purified and crystallized to the resolution of 2.1 Angstrom in the condition of 19%~21% PEG8000, 200 mmol/L Mg(Ac)2·4H2O. Structural based fragment screening was then performed against 768 fragment chemical compounds. These small molecular fragments were soaked with the PTP1B crystals, and three of them were found to bind at the active site A of PTP1B in the crystals. Then 14 kinds of published molecules which bind to the second active site (site B) were chosen. With the structures of these bound fragment compounds, hundreds of moleculars were calculated by computer aided drug design. Compound 20 was selected as the target compound, and it was synthesized by 13 steps with the total yield of 1.7%. The structure of compound 20 was characterized by 1H NMR and HRMS data. Bioassay of inhibition of PTP1B by the new compounds revealed its IC50 at (3.4±1.2) μmol/L, which was better than that of the positive control drug-sodium vanadate. The result of measurement of glucose uptake by insulin resistant HepG2 cells showed that the new compound can improve glucose uptake and had similar effect as Pioglitazone. The acute toxicity of the new compound was tested by using zebrafish larvae at two different concentrations (50 and 500 μmol/L). The results showed there was no significant difference in heart rate, blood flow and morphology between the experiment and control group of zebrafish. All the results above implied the new compound has a good inhibition on PTP1B and low acute toxicity. It may be a potential lead compound for further drug discovery.
Protein tyrosine phosphatase 1B (PTP1B) is an enzyme that downregulates the insulin receptor. It has been considered as one of the drug targets of diabetes, and the inhibitors for PTP1B to treat type II diabetes have received considerable attention. The study reports a discovery of a new lead compound inhibiting PTP1B. In this work, PTP1B protein was expressed, purified and crystallized to the resolution of 2.1 Angstrom in the condition of 19%~21% PEG8000, 200 mmol/L Mg(Ac)2·4H2O. Structural based fragment screening was then performed against 768 fragment chemical compounds. These small molecular fragments were soaked with the PTP1B crystals, and three of them were found to bind at the active site A of PTP1B in the crystals. Then 14 kinds of published molecules which bind to the second active site (site B) were chosen. With the structures of these bound fragment compounds, hundreds of moleculars were calculated by computer aided drug design. Compound 20 was selected as the target compound, and it was synthesized by 13 steps with the total yield of 1.7%. The structure of compound 20 was characterized by 1H NMR and HRMS data. Bioassay of inhibition of PTP1B by the new compounds revealed its IC50 at (3.4±1.2) μmol/L, which was better than that of the positive control drug-sodium vanadate. The result of measurement of glucose uptake by insulin resistant HepG2 cells showed that the new compound can improve glucose uptake and had similar effect as Pioglitazone. The acute toxicity of the new compound was tested by using zebrafish larvae at two different concentrations (50 and 500 μmol/L). The results showed there was no significant difference in heart rate, blood flow and morphology between the experiment and control group of zebrafish. All the results above implied the new compound has a good inhibition on PTP1B and low acute toxicity. It may be a potential lead compound for further drug discovery.
2015, 74(2): 165-171
doi: 10.6023/A15090628
Abstract:
Three new D-π-A type quinoxalines modified with tetraphenylethylenes BTPQ, DBTPQ and BTBQ were synthesized via Suzuki coupling reactions between (4-(1,2,2-triphenylvinyl)phenyl)boronic acid and bromo aromatic hydrocarbons. It was found that BTPQ and DBTPQ, in which tetraphenylethylenes were substituted on 5,8-positions of quinoxalines gave the absortion bands at 316 nm and 303 nm, respectively, originated from π-π* transition. For BTBQ, in which tetraphenylethylene units were located at 2,3-positions of quinoxaline, the π-π* transition absorption blue-shifted to 287 nm on account of the poor planarity and low conjugation. Meanwhile, the intermolecular charge transfer (ICT) emission could be detected for BTPQ and DBTPQ, whose emission bands red-shifted significantly and emission intensities decreased with increasing the solvent polarities. It should be noted that the three compounds exhibited aggregation-induced emission (AIE) behaviors. For instance, when the water faction in the THF solution increased to 90%, the emission intensity at ca. 400 nm for BTBQ, was ca. 54 times higher than that in THF. Additionally, trifluoroacetic acid (TFA) could lead to the changes of color and emitting color of BTBQ in solution as well as in solid state due to the formation of protonated quinoxaline. We found that the grey solid of BTBQ could turn into red one upon exposed to gaseous TFA, accompanying with the quench of the emission. Other kinds of acids of HCl, HNO3 and acetic acid also could lead to the fluorescence quenching of solid BTBQ to some extent. Therefore, BTBQ could be used as sensory material to detect acid vapors by naked eyes. However, the protonation would be prohibited in BTPQ and DBTPQ on account of the steric effect of tetraphenylethylene units linked to 5,8-positions of quinoxaline, so BTPQ and DBTPQ could not detect acid. Interestingly, the solid emitting colors of BTPQ as well as DBTPQ were quite different before and after grinding, exhibiting mechanochromic properties. The as-prepared crystal of BTPQ emitting blue light under UV irradiation could be changed into amorphous powder with bluish green emission. The XRD patterns suggested that the mechanochromism was originated from the transition between the crystalline and amorphous states. Such mechanochromism was reversible under the treatment of grinding and heating/fuming with DCM.
Three new D-π-A type quinoxalines modified with tetraphenylethylenes BTPQ, DBTPQ and BTBQ were synthesized via Suzuki coupling reactions between (4-(1,2,2-triphenylvinyl)phenyl)boronic acid and bromo aromatic hydrocarbons. It was found that BTPQ and DBTPQ, in which tetraphenylethylenes were substituted on 5,8-positions of quinoxalines gave the absortion bands at 316 nm and 303 nm, respectively, originated from π-π* transition. For BTBQ, in which tetraphenylethylene units were located at 2,3-positions of quinoxaline, the π-π* transition absorption blue-shifted to 287 nm on account of the poor planarity and low conjugation. Meanwhile, the intermolecular charge transfer (ICT) emission could be detected for BTPQ and DBTPQ, whose emission bands red-shifted significantly and emission intensities decreased with increasing the solvent polarities. It should be noted that the three compounds exhibited aggregation-induced emission (AIE) behaviors. For instance, when the water faction in the THF solution increased to 90%, the emission intensity at ca. 400 nm for BTBQ, was ca. 54 times higher than that in THF. Additionally, trifluoroacetic acid (TFA) could lead to the changes of color and emitting color of BTBQ in solution as well as in solid state due to the formation of protonated quinoxaline. We found that the grey solid of BTBQ could turn into red one upon exposed to gaseous TFA, accompanying with the quench of the emission. Other kinds of acids of HCl, HNO3 and acetic acid also could lead to the fluorescence quenching of solid BTBQ to some extent. Therefore, BTBQ could be used as sensory material to detect acid vapors by naked eyes. However, the protonation would be prohibited in BTPQ and DBTPQ on account of the steric effect of tetraphenylethylene units linked to 5,8-positions of quinoxaline, so BTPQ and DBTPQ could not detect acid. Interestingly, the solid emitting colors of BTPQ as well as DBTPQ were quite different before and after grinding, exhibiting mechanochromic properties. The as-prepared crystal of BTPQ emitting blue light under UV irradiation could be changed into amorphous powder with bluish green emission. The XRD patterns suggested that the mechanochromism was originated from the transition between the crystalline and amorphous states. Such mechanochromism was reversible under the treatment of grinding and heating/fuming with DCM.
2015, 74(2): 172-178
doi: 10.6023/A15100664
Abstract:
Effect of temperature on near-infrared (NIR) spectra has been studied and applied to structural and quantitative analyses. To investigate the effect of temperature on NIR spectra of alkyl organic system, n-alkanes were studied in this work. NIR spectra of pure n-alkanes (hexane to decane), binary (hexane and octane) and ternary (octane, nonane and decane) mixtures were measured. In the experiments, temperature was controlled to change from 60 to 20℃ with a step of ca. 5℃. Comparing the spectra at different temperatures, only a little difference in peak intensity of some bands can be found. Therefore, alternating trilinear decomposition (ATLD) algorithm was adopted to analyze the three-order data matrix. The results show that two spectral loadings are obtained because the influence of temperature on the spectra of terminal ethyl (C2H5) groups differs from that of mid-chain methylene (CH2) groups. Furthermore, the temperature scores of CH2 and C2H5 groups decrease linearly with temperature, implying that the temperature effect can be quantitatively described by a quantitative spectra-temperature relationship (QSTR) model. The QSTR model provides an efficient way to predict the temperature of n-alkane solutions. Good linearity also exists between sample scores and carbon number or the relative content of CH2 and C2H5 groups in the molecules of the n-alkanes. Linear models between the two scores and the relative content of CH2 and C2H5 groups are obtained, respectively, using the least square fitting of the score and the relative contents. The model can be used for prediction of the relative content of CH2 and C2H5 groups in mixtures, which can further be used to estimate the composition of the mixtures. Furthermore, the relationship between the scores and the carbon atom numbers is modeled using multivariate linear regression (MLR). The composition of n-alkane mixtures can also be estimated through the predicted carbon number using the MLR model. These models are validated by binary and ternary mixtures of the n-alkanes. It was indicated that the relative contents of CH2 and C2H5 groups or the carbon atom number can be predicted using the models. Therefore, a new way for quantitative estimation of the composition in n-alkane mixtures was developed using the temperature effect of the near-infrared spectra.
Effect of temperature on near-infrared (NIR) spectra has been studied and applied to structural and quantitative analyses. To investigate the effect of temperature on NIR spectra of alkyl organic system, n-alkanes were studied in this work. NIR spectra of pure n-alkanes (hexane to decane), binary (hexane and octane) and ternary (octane, nonane and decane) mixtures were measured. In the experiments, temperature was controlled to change from 60 to 20℃ with a step of ca. 5℃. Comparing the spectra at different temperatures, only a little difference in peak intensity of some bands can be found. Therefore, alternating trilinear decomposition (ATLD) algorithm was adopted to analyze the three-order data matrix. The results show that two spectral loadings are obtained because the influence of temperature on the spectra of terminal ethyl (C2H5) groups differs from that of mid-chain methylene (CH2) groups. Furthermore, the temperature scores of CH2 and C2H5 groups decrease linearly with temperature, implying that the temperature effect can be quantitatively described by a quantitative spectra-temperature relationship (QSTR) model. The QSTR model provides an efficient way to predict the temperature of n-alkane solutions. Good linearity also exists between sample scores and carbon number or the relative content of CH2 and C2H5 groups in the molecules of the n-alkanes. Linear models between the two scores and the relative content of CH2 and C2H5 groups are obtained, respectively, using the least square fitting of the score and the relative contents. The model can be used for prediction of the relative content of CH2 and C2H5 groups in mixtures, which can further be used to estimate the composition of the mixtures. Furthermore, the relationship between the scores and the carbon atom numbers is modeled using multivariate linear regression (MLR). The composition of n-alkane mixtures can also be estimated through the predicted carbon number using the MLR model. These models are validated by binary and ternary mixtures of the n-alkanes. It was indicated that the relative contents of CH2 and C2H5 groups or the carbon atom number can be predicted using the models. Therefore, a new way for quantitative estimation of the composition in n-alkane mixtures was developed using the temperature effect of the near-infrared spectra.
2015, 74(2): 179-184
doi: 10.6023/A15090603
Abstract:
A novel diboron-bridged ladder-type molecule with extended π-conjugated skeleton has been designed and synthesized. Single crystal of the compound has been grown by the method of vacuum sublimation and the molecular structure determined by X-ray diffraction analysis demonstrate that this ladder-type molecule has a seven-ring fused skeleton, which is almost coplanar. And the two mesityl groups coordinated to each boron atom can effectively keep the luminescent units apart. No π-π interaction can be observed between the two extended π-conjugated planes. In the packing structures, we cannot find the intramolecular hydrogen bond, C-H…π interaction and other weak interaction. Based on UV-vis absorption and fluorescence emission spectra, the longest absorption band is peaked at 372 nm in dichloromethane solution and the emission band is at 544 nm which has a large stokes shift of 8499 cm-1. In the solid state, the compound shows yellow fluorescence with emission peak at 582 nm. The compound in condensed phase displays only slightly red shifted emission spectra and almost the same fluorescence quantum yield compared to that in dispersed phase, which is attributed to the bulky side groups on the boron atoms. The compound possesses a very high melting point (Tm=352℃) and decomposition temperature (Td5=360℃) due to the rigid π-conjugated plane that indicates its good thermal stability. The compound has two pairs of reversible reduction peaks and an irreversible oxidation peak which are similar to the reported four-coordinate compounds. The cyclic voltammogram curves indicate boron chelation can greatly lower the lowest unoccupied molecular orbital (LUMO). Thus, it makes cathodic reductions easier and thereby endows the π-conjugated ladder with enhanced electron-accepting nature. The electrochemical property suggests that the compound is suitable as an electron-transporting layer in organic light-emitting diode (OLED) devices. To obtain a deeper insight into the electronic structure and energy levels of the π-conjugated skeleton, density functional theory (DFT) calculations were performed. The LUMOs are delocalized on the entire seven-ring π-conjugated ladder while the central benzene ring and the mesityl chelated with the boron atom make a main contribution to the HOMOs. The general trend of the calculated HOMO/LUMO levels and energy gaps are basically consistent with the electrochemical and the photophysical data. Therefore, we fabricated OLEDs devices using the molecule as emitter and/or electron-transporting layers, which showed good EL performance.
A novel diboron-bridged ladder-type molecule with extended π-conjugated skeleton has been designed and synthesized. Single crystal of the compound has been grown by the method of vacuum sublimation and the molecular structure determined by X-ray diffraction analysis demonstrate that this ladder-type molecule has a seven-ring fused skeleton, which is almost coplanar. And the two mesityl groups coordinated to each boron atom can effectively keep the luminescent units apart. No π-π interaction can be observed between the two extended π-conjugated planes. In the packing structures, we cannot find the intramolecular hydrogen bond, C-H…π interaction and other weak interaction. Based on UV-vis absorption and fluorescence emission spectra, the longest absorption band is peaked at 372 nm in dichloromethane solution and the emission band is at 544 nm which has a large stokes shift of 8499 cm-1. In the solid state, the compound shows yellow fluorescence with emission peak at 582 nm. The compound in condensed phase displays only slightly red shifted emission spectra and almost the same fluorescence quantum yield compared to that in dispersed phase, which is attributed to the bulky side groups on the boron atoms. The compound possesses a very high melting point (Tm=352℃) and decomposition temperature (Td5=360℃) due to the rigid π-conjugated plane that indicates its good thermal stability. The compound has two pairs of reversible reduction peaks and an irreversible oxidation peak which are similar to the reported four-coordinate compounds. The cyclic voltammogram curves indicate boron chelation can greatly lower the lowest unoccupied molecular orbital (LUMO). Thus, it makes cathodic reductions easier and thereby endows the π-conjugated ladder with enhanced electron-accepting nature. The electrochemical property suggests that the compound is suitable as an electron-transporting layer in organic light-emitting diode (OLED) devices. To obtain a deeper insight into the electronic structure and energy levels of the π-conjugated skeleton, density functional theory (DFT) calculations were performed. The LUMOs are delocalized on the entire seven-ring π-conjugated ladder while the central benzene ring and the mesityl chelated with the boron atom make a main contribution to the HOMOs. The general trend of the calculated HOMO/LUMO levels and energy gaps are basically consistent with the electrochemical and the photophysical data. Therefore, we fabricated OLEDs devices using the molecule as emitter and/or electron-transporting layers, which showed good EL performance.
2015, 74(2): 191-198
doi: 10.6023/A15040257
Abstract:
In this paper we report the infrared to visible upconversion(UC) luminescence properties of Hf4+ and Zr4+ codoped NaYF4:Yb3+/Tm3+. Samples were synthesised by hydrothermal method. Concentration of Tm3+ and Yb3+ ions were fixed to be 2 mol% and 5 mol% for all samples, respectively. NaY0.93-xYb0.05Tm0.02F4 was tridoped with 0, 2, 4, 6, 8 mol% Hf4+ or Zr4+ and corresponding samples were named as Hf0, Hf2, Hf4, Hf6, Hf8 and Zr0, Zr2, Zr4, Zr6, Zr8, respectively. In a typical procedure, trivalent nitrate stock solutions of 0.2 mol/L were prepared at first by dissolving the corresponding metal oxide in concentrated nitric acid or hydrofluoric acid at elevated temperatures. And then, a certain mole percentage of trivalent nitrate solutions were added into 20 mL 0.04 mmol EDTA aqueous solution. After vigorous stirring for 30 min, 25 mL ethanol solution containing 0.2 mmol NaF, 0.2 mmol NH4HF2 and corresponding stoichiometric amount Hf4+ or Zr4+ were dropwise added into the solution, and then pH value of solution was adjusted to 3.0 by addition 1 mol/L HF, and stirring continued for 30 min. Then the emulsion mixture was moved to PTFE-lined high pressure pot and incubated in oven at 180℃ for 12 h. The final products were collected, washed several times with water and ethanol alternately, and gathered by centrifugation, and then dried in oven at 60℃. Crystal microstructure, morphology and UC luminescence properties of samples were investigated by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and upconversion photoluminescence spectra. Results revealed the bond distance of F1-Y and F2-Y become close with the rising of Hf4+ or Zr4+ codoped concentration, indicating crystal field asymmetry of rare earth ions were tuned effectively by Hf4+ or Zr4+ codoping. Electron hypersensitive transition was promoted, and the intensity of 802 nm emission was enhanced obviously. Hf4+ ion was a better dopant than Zr4+, for the extranuclear electronic structure of Hf4+ was the same with rare earth ions, and Hf4+ ion was involved in UC process as a migrator to improve Tm3+ upper state levels'population. UC luminescence of Hf4+ codoped sample were enhanced obviously, especially the shortwave emissions. The reported work establishes the understanding of Hf4+ as a migrator for Tm3+ ions upconversion luminescence, which may be helpful for design and synthesis of high-performance upconversion materials.
In this paper we report the infrared to visible upconversion(UC) luminescence properties of Hf4+ and Zr4+ codoped NaYF4:Yb3+/Tm3+. Samples were synthesised by hydrothermal method. Concentration of Tm3+ and Yb3+ ions were fixed to be 2 mol% and 5 mol% for all samples, respectively. NaY0.93-xYb0.05Tm0.02F4 was tridoped with 0, 2, 4, 6, 8 mol% Hf4+ or Zr4+ and corresponding samples were named as Hf0, Hf2, Hf4, Hf6, Hf8 and Zr0, Zr2, Zr4, Zr6, Zr8, respectively. In a typical procedure, trivalent nitrate stock solutions of 0.2 mol/L were prepared at first by dissolving the corresponding metal oxide in concentrated nitric acid or hydrofluoric acid at elevated temperatures. And then, a certain mole percentage of trivalent nitrate solutions were added into 20 mL 0.04 mmol EDTA aqueous solution. After vigorous stirring for 30 min, 25 mL ethanol solution containing 0.2 mmol NaF, 0.2 mmol NH4HF2 and corresponding stoichiometric amount Hf4+ or Zr4+ were dropwise added into the solution, and then pH value of solution was adjusted to 3.0 by addition 1 mol/L HF, and stirring continued for 30 min. Then the emulsion mixture was moved to PTFE-lined high pressure pot and incubated in oven at 180℃ for 12 h. The final products were collected, washed several times with water and ethanol alternately, and gathered by centrifugation, and then dried in oven at 60℃. Crystal microstructure, morphology and UC luminescence properties of samples were investigated by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and upconversion photoluminescence spectra. Results revealed the bond distance of F1-Y and F2-Y become close with the rising of Hf4+ or Zr4+ codoped concentration, indicating crystal field asymmetry of rare earth ions were tuned effectively by Hf4+ or Zr4+ codoping. Electron hypersensitive transition was promoted, and the intensity of 802 nm emission was enhanced obviously. Hf4+ ion was a better dopant than Zr4+, for the extranuclear electronic structure of Hf4+ was the same with rare earth ions, and Hf4+ ion was involved in UC process as a migrator to improve Tm3+ upper state levels'population. UC luminescence of Hf4+ codoped sample were enhanced obviously, especially the shortwave emissions. The reported work establishes the understanding of Hf4+ as a migrator for Tm3+ ions upconversion luminescence, which may be helpful for design and synthesis of high-performance upconversion materials.
2015, 74(2): 199-207
doi: 10.6023/A15090636
Abstract:
In this paper, dual functional monomers (concanavalin A and aminobenzeneboronic acid) method is applied to molecular imprinting technique, three synthetic methods of functional monomer were designed and their ability to adsorb glucose was evaluated. Step-by-step method (A1) was found to be a good synthetic method for selective adsorption, which could adsorb glucose powerfully. A kind of magnetic molecularly imprinted polymers (MMIPs) was synthesized by step-by-step method, in which superparamagnetic Fe3O4 nanoparticles were firstly synthesized by hydrothermal synthetic method and uniform SiO2-coated Fe3O4 (Fe3O4@SiO2) nanoparticles were prepared via Sol-gel method. The following Fe3O4@SiO2 reacted with (3-aminopropyl)triethoxysilane to produce Fe3O4@SiO2@NH2. The aminated nanoparticles combine with concanavalin A to form Fe3O4@SiO2@NH2@ConA in the presence of disuccinimidyl suberate. Subsequently, the single-functionalized nanoparticles binded with aminobenzeneboronic acid to form Fe3O4@SiO2@NH2@APBA-ConA in the presence of disuccinimidyl suberate. Eventually, the MMIPs for glucose selective recognition, with core-shell structure, were synthesized by surface molecular imprinting method, using glucose (Glu) as template molecule, concanavalin A (ConA) and aminobenzeneboronic acid (APBA) as dual functional monomers, N,N'-methylenebisacrylamide as the crosslinking agent, ammonium peroxydisulfate as the initiator, superparamagnetic nanoparticles as magnetic carrier. The MMIPs were characterized by X-ray diffraction (XRD), energy dispersive spectrometer (EDS), scanning electron microscopy (SEM), Fourier transform infrared spectra (FT-IR), vibrating sample magnetometer (VSM) and thermogravimetric analysis (TGA). The SEM showed the nanoparticles were highly dispersive and uniform. The EDS, FT-IR and TGA revealed the success of step-by-step method. The VSM demonstrated the saturation magnetization values of Fe3O4 and MMIPs were 96.661 emu/g and 45.064 emu/g, respectively. The study on kinetics of MMIPs showed that the adsorption reaction could be considered as a second order reaction. The thermodynamics research revealed that the adsorption of MMIPs was fitted to Langmuir isotherms. The study on selective adsorption displayed that MMIPs had maximum imprinting factor of 2.93 and best selectivity. The class specific study of MMIPs showed that it could be applied to extraction and separation of glucosides.
In this paper, dual functional monomers (concanavalin A and aminobenzeneboronic acid) method is applied to molecular imprinting technique, three synthetic methods of functional monomer were designed and their ability to adsorb glucose was evaluated. Step-by-step method (A1) was found to be a good synthetic method for selective adsorption, which could adsorb glucose powerfully. A kind of magnetic molecularly imprinted polymers (MMIPs) was synthesized by step-by-step method, in which superparamagnetic Fe3O4 nanoparticles were firstly synthesized by hydrothermal synthetic method and uniform SiO2-coated Fe3O4 (Fe3O4@SiO2) nanoparticles were prepared via Sol-gel method. The following Fe3O4@SiO2 reacted with (3-aminopropyl)triethoxysilane to produce Fe3O4@SiO2@NH2. The aminated nanoparticles combine with concanavalin A to form Fe3O4@SiO2@NH2@ConA in the presence of disuccinimidyl suberate. Subsequently, the single-functionalized nanoparticles binded with aminobenzeneboronic acid to form Fe3O4@SiO2@NH2@APBA-ConA in the presence of disuccinimidyl suberate. Eventually, the MMIPs for glucose selective recognition, with core-shell structure, were synthesized by surface molecular imprinting method, using glucose (Glu) as template molecule, concanavalin A (ConA) and aminobenzeneboronic acid (APBA) as dual functional monomers, N,N'-methylenebisacrylamide as the crosslinking agent, ammonium peroxydisulfate as the initiator, superparamagnetic nanoparticles as magnetic carrier. The MMIPs were characterized by X-ray diffraction (XRD), energy dispersive spectrometer (EDS), scanning electron microscopy (SEM), Fourier transform infrared spectra (FT-IR), vibrating sample magnetometer (VSM) and thermogravimetric analysis (TGA). The SEM showed the nanoparticles were highly dispersive and uniform. The EDS, FT-IR and TGA revealed the success of step-by-step method. The VSM demonstrated the saturation magnetization values of Fe3O4 and MMIPs were 96.661 emu/g and 45.064 emu/g, respectively. The study on kinetics of MMIPs showed that the adsorption reaction could be considered as a second order reaction. The thermodynamics research revealed that the adsorption of MMIPs was fitted to Langmuir isotherms. The study on selective adsorption displayed that MMIPs had maximum imprinting factor of 2.93 and best selectivity. The class specific study of MMIPs showed that it could be applied to extraction and separation of glucosides.
