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2020 Volume 78 Issue 1
2020, 78(1): 9-22
doi: 10.6023/A19090340
Abstract:
Carbon dioxide (CO2) is an abundant, inexpensive, non-toxic and renewable C1 resource, and it is also a kind of green monomer. The polymerizations based on CO2 have been one of the hot research topics. The copolymerization of CO2 and epoxide monomers was widely studied in the past few years and has been industrialized. Some new polymerizations based on CO2 have also been reported recently. There are two ways to produce polymeric materials from CO2. One is converting CO2 into monomers for further ring opening or step growth polymerizations, such as lactone, cyclic carbonates, furan-2, 5-dicarboxylic acid. Another is directly using CO2 as a monomer for the copolymerization with other monomers to generate polymers. They are both significant for developing new polymerizations based on CO2 and expanding CO2-based polymeric materials. The advances in converting CO2 into polymeric materials during the past few years are summarized in this review and the perspective in this area is discussed.
Carbon dioxide (CO2) is an abundant, inexpensive, non-toxic and renewable C1 resource, and it is also a kind of green monomer. The polymerizations based on CO2 have been one of the hot research topics. The copolymerization of CO2 and epoxide monomers was widely studied in the past few years and has been industrialized. Some new polymerizations based on CO2 have also been reported recently. There are two ways to produce polymeric materials from CO2. One is converting CO2 into monomers for further ring opening or step growth polymerizations, such as lactone, cyclic carbonates, furan-2, 5-dicarboxylic acid. Another is directly using CO2 as a monomer for the copolymerization with other monomers to generate polymers. They are both significant for developing new polymerizations based on CO2 and expanding CO2-based polymeric materials. The advances in converting CO2 into polymeric materials during the past few years are summarized in this review and the perspective in this area is discussed.
2020, 78(1): 23-33
doi: 10.6023/A19110407
Abstract:
Phosphorescent ion-paired complexes, which consist of two oppositely charged transition metal complexes with excellent photophysical properties, are called "soft salts" because of the soft nature of the ions. In recent decades, phosphorescent soft salt complexes have gained an increasing attention and this review aims to summarize the syntheses and photophysical properties of those complexes, and recent advances of them in different optoelectronic applications. Generally, phosphorescent soft salt complexes are synthesized via salt metathesis reactions between two oppositely charged organometallic components. By changing the chemical structure of ligands or the metal centers of the different ionic complexes, the photophysical properties of soft salt complexes can be easily regulated. Moreover, most of the soft salt complexes show concentration-dependent photoluminescence (PL) spectra due to the energy transfer between positive and negative ions. Thus, white light emission can be obtained by dissolving ion-paired complex consisting of two ionic components with blue and yellow emission in solution at certain concentration. Considering the excellent photophysical properties and easy tunability of phosphorescent soft salt complexes, the application of them in diverse optoelectronic fields, such as organic light emitting diodes, bioimaging, photodynamic therapy, electrochromic luminescence devices, and so on, have been explored. For example, Thompson and co-workers utilized iridium(Ⅲ) complexes based phosphorescent soft salts to fabricate organic light emitting diodes for the first time. Our group have first developed soft salts based phosphorescent probes for ratiometric and lifetime imaging of pH and oxygen changes in living cells. In addition, we have found that soft salt complexes showed an enhanced singlet oxygen generation rate due to the efficient energy transfer between two ionic components, which has great potential to act as a photosensitizer for photodynamic therapy of cancer cells. Huang and co-workers have proposed a new strategy to design electrochromic luminescence materials based on soft salt complexes, which display tunable and reversible electrochromic luminescence. In summary, phosphorescent soft salt complexes possessing excellent photophysical properties show great potential in diverse optoelectronic applications.
Phosphorescent ion-paired complexes, which consist of two oppositely charged transition metal complexes with excellent photophysical properties, are called "soft salts" because of the soft nature of the ions. In recent decades, phosphorescent soft salt complexes have gained an increasing attention and this review aims to summarize the syntheses and photophysical properties of those complexes, and recent advances of them in different optoelectronic applications. Generally, phosphorescent soft salt complexes are synthesized via salt metathesis reactions between two oppositely charged organometallic components. By changing the chemical structure of ligands or the metal centers of the different ionic complexes, the photophysical properties of soft salt complexes can be easily regulated. Moreover, most of the soft salt complexes show concentration-dependent photoluminescence (PL) spectra due to the energy transfer between positive and negative ions. Thus, white light emission can be obtained by dissolving ion-paired complex consisting of two ionic components with blue and yellow emission in solution at certain concentration. Considering the excellent photophysical properties and easy tunability of phosphorescent soft salt complexes, the application of them in diverse optoelectronic fields, such as organic light emitting diodes, bioimaging, photodynamic therapy, electrochromic luminescence devices, and so on, have been explored. For example, Thompson and co-workers utilized iridium(Ⅲ) complexes based phosphorescent soft salts to fabricate organic light emitting diodes for the first time. Our group have first developed soft salts based phosphorescent probes for ratiometric and lifetime imaging of pH and oxygen changes in living cells. In addition, we have found that soft salt complexes showed an enhanced singlet oxygen generation rate due to the efficient energy transfer between two ionic components, which has great potential to act as a photosensitizer for photodynamic therapy of cancer cells. Huang and co-workers have proposed a new strategy to design electrochromic luminescence materials based on soft salt complexes, which display tunable and reversible electrochromic luminescence. In summary, phosphorescent soft salt complexes possessing excellent photophysical properties show great potential in diverse optoelectronic applications.
2020, 78(1): 34-55
doi: 10.6023/A19090330
Abstract:
Lanthanide-based single molecule magnets have received tremendous attentions in recent years owing to the strong magnetic anisotropies of the lanthanide ions arising from the strong spin-orbital couplings. Cyclic metal clusters, also called molecular wheels or metallacrown ether, are a subclass of metal clusters. From the magnetic point of view, cyclic transition metal clusters can be devided into three types, e.g. ferromagnetically coupled cyclic clusters which favor single molecule magnet behavior, and antiferromagnetically coupled even-or odd-numbered cyclic clusters with S=0 or S=1/2 ground state. The magnetic properties of lanthanide-based cyclic clusters are more complicated because the magnetic interactions between the lanthanide ions are extremely weak. The overall magnetic behavior is largely dominated by the single ion anisotropy and the dipole-dipole interactions between the metal ions. When the anisotropy axes of the lanthanide ions in the cyclic clusters are arranged in a toroidal manner, single-molecule toroics could be achieved. Therefore, the design and synthesis of cyclic lanthanide-based clusters can provide not only new materials with architectural beauty and single molecule magnet behavior, but also single-molecule toroics with vortex distribution of the magnetic dipoles of lanthanide ions, which would have potential applications in information storage, quantum computing, spintronic devices and multiferroic materials. Noting that lanthanide-based single-molecule toroics have been described detailly in several reviews, this article will summarize the current status of the cyclic lanthanide clusters with the focus on the design and assembly strategies, the structural characteristics and magnetic studies. Most work have been concentrated on the Ln3, Ln4 and Ln6 cyclic clusters, including those containing oxygen centers. Examples of even-numbered cyclic clusters Lnx (x ≥ 8) are much less, and those of odd-numbered cyclic clusters Lnx (x ≥ 5) are rare. As the cyclic clusters are frequently distorted to different extent, many of them exhibit single molecule magnet behavior, and only few of them show toroic magnetization. It remains future challenges to design and synthesize new lanthanide-based cyclic clusters with regular and flat geometries and toroically arranged magnetic moments, and to achieve the multifunctions in the same molecular composite.
Lanthanide-based single molecule magnets have received tremendous attentions in recent years owing to the strong magnetic anisotropies of the lanthanide ions arising from the strong spin-orbital couplings. Cyclic metal clusters, also called molecular wheels or metallacrown ether, are a subclass of metal clusters. From the magnetic point of view, cyclic transition metal clusters can be devided into three types, e.g. ferromagnetically coupled cyclic clusters which favor single molecule magnet behavior, and antiferromagnetically coupled even-or odd-numbered cyclic clusters with S=0 or S=1/2 ground state. The magnetic properties of lanthanide-based cyclic clusters are more complicated because the magnetic interactions between the lanthanide ions are extremely weak. The overall magnetic behavior is largely dominated by the single ion anisotropy and the dipole-dipole interactions between the metal ions. When the anisotropy axes of the lanthanide ions in the cyclic clusters are arranged in a toroidal manner, single-molecule toroics could be achieved. Therefore, the design and synthesis of cyclic lanthanide-based clusters can provide not only new materials with architectural beauty and single molecule magnet behavior, but also single-molecule toroics with vortex distribution of the magnetic dipoles of lanthanide ions, which would have potential applications in information storage, quantum computing, spintronic devices and multiferroic materials. Noting that lanthanide-based single-molecule toroics have been described detailly in several reviews, this article will summarize the current status of the cyclic lanthanide clusters with the focus on the design and assembly strategies, the structural characteristics and magnetic studies. Most work have been concentrated on the Ln3, Ln4 and Ln6 cyclic clusters, including those containing oxygen centers. Examples of even-numbered cyclic clusters Lnx (x ≥ 8) are much less, and those of odd-numbered cyclic clusters Lnx (x ≥ 5) are rare. As the cyclic clusters are frequently distorted to different extent, many of them exhibit single molecule magnet behavior, and only few of them show toroic magnetization. It remains future challenges to design and synthesize new lanthanide-based cyclic clusters with regular and flat geometries and toroically arranged magnetic moments, and to achieve the multifunctions in the same molecular composite.
2020, 78(1): 56-62
doi: 10.6023/A19110406
Abstract:
It is an important pathway in the field of phosphorescent organic light-emitting diodes (PhOLED) that endowing iridium (Ⅲ) emitters with the features of low-cost, decent photoelectric properties, and high doping-concentration application by harmonizing electronic and steric effects of corresponding ligands. Based on our previous research that introducing spiro ligand into IrⅢ complexes to protect emitting-center and to suppress concentration quenching, herein, for pushing the emission to orange region, we extend the conjugated structure of spiro[fluorene-9, 9'-xanthene] (SFX) by connected benzo[d]-thiazole-2-yl on the fluorene moiety of SFX via Suzuki-Miyaura coupling, acting as a new spiro ligand. A homoleptic IrⅢ complex, fac-Ir(SFXbtz)3, was synthesized successfully, and the structure and the photophysical and electrochemical properties were studied by nuclear magnetic resonance, single crystal X-ray diffraction, absorption and emission measurements, as well as cyclic voltammetry. The crystallographic data revealed an enlarged Ir…Ir distance and weakly intermolecular π-π interactions between the spiro ligands. The emission spectrum of fac-Ir(SFXbtz)3 showed a maximum peak at 587 nm and a shoulder peak at 635 nm with a photoluminescence (PL) quantum yield (QY) of 64.7% (relative to tris[2-phenylpyridinato-C2, N]iridium(Ⅲ), PLQY=40%). The highest occupied molecular orbital level was determined to be -5.28 eV according to the onset oxidation potential (0.48 V). In view of the orange light-emitting and the high PLQY of fac-Ir(SFXbtz)3, the monochromatic and two-element white PhOLED were fabricated to investigate its electroluminescence (EL) performance in high doping concentrations, ω=12% for monochromatic device and ω=15% for two-element white device, respectively. The EL spectrum of the monochromatic PhOLED (device D1) using common 4, 4'-bis(N-carbazolyl)-1, 1'-biphenyl as host exhibits two emission peaks, a maximum emission peak at 581 nm and shoulder emission peak at 631 nm, corresponding to its PL spectrum. The device D1 shows a peak performance of 10.8 cd·A-1 and 8.4 lm·W-1, maximum brightness of 7217 cd·m-2, respectively. The two-element white PhOLED selecting bis[2-(4, 6-difluorophenyl)pyridinato-C2, N](picolinato)iridium(Ⅲ) as complementary blue-light component, possesses a peak performance of 11.6 cd·A-1 and 8.0 lm·W-1, maximum brightness of 8763 cd·m-2, and stabilized CIE 1931 (0.34~0.37, 0.36~0.38) under operated voltages of 3~9 V, respectively. These results indicate that the fac-Ir(SFXbtz)3 is a potential phosphor for efficient orange PhOLED, possessing the advantages of low-cost, suitable doping in high concentration, and stabilized color coordinates.
It is an important pathway in the field of phosphorescent organic light-emitting diodes (PhOLED) that endowing iridium (Ⅲ) emitters with the features of low-cost, decent photoelectric properties, and high doping-concentration application by harmonizing electronic and steric effects of corresponding ligands. Based on our previous research that introducing spiro ligand into IrⅢ complexes to protect emitting-center and to suppress concentration quenching, herein, for pushing the emission to orange region, we extend the conjugated structure of spiro[fluorene-9, 9'-xanthene] (SFX) by connected benzo[d]-thiazole-2-yl on the fluorene moiety of SFX via Suzuki-Miyaura coupling, acting as a new spiro ligand. A homoleptic IrⅢ complex, fac-Ir(SFXbtz)3, was synthesized successfully, and the structure and the photophysical and electrochemical properties were studied by nuclear magnetic resonance, single crystal X-ray diffraction, absorption and emission measurements, as well as cyclic voltammetry. The crystallographic data revealed an enlarged Ir…Ir distance and weakly intermolecular π-π interactions between the spiro ligands. The emission spectrum of fac-Ir(SFXbtz)3 showed a maximum peak at 587 nm and a shoulder peak at 635 nm with a photoluminescence (PL) quantum yield (QY) of 64.7% (relative to tris[2-phenylpyridinato-C2, N]iridium(Ⅲ), PLQY=40%). The highest occupied molecular orbital level was determined to be -5.28 eV according to the onset oxidation potential (0.48 V). In view of the orange light-emitting and the high PLQY of fac-Ir(SFXbtz)3, the monochromatic and two-element white PhOLED were fabricated to investigate its electroluminescence (EL) performance in high doping concentrations, ω=12% for monochromatic device and ω=15% for two-element white device, respectively. The EL spectrum of the monochromatic PhOLED (device D1) using common 4, 4'-bis(N-carbazolyl)-1, 1'-biphenyl as host exhibits two emission peaks, a maximum emission peak at 581 nm and shoulder emission peak at 631 nm, corresponding to its PL spectrum. The device D1 shows a peak performance of 10.8 cd·A-1 and 8.4 lm·W-1, maximum brightness of 7217 cd·m-2, respectively. The two-element white PhOLED selecting bis[2-(4, 6-difluorophenyl)pyridinato-C2, N](picolinato)iridium(Ⅲ) as complementary blue-light component, possesses a peak performance of 11.6 cd·A-1 and 8.0 lm·W-1, maximum brightness of 8763 cd·m-2, and stabilized CIE 1931 (0.34~0.37, 0.36~0.38) under operated voltages of 3~9 V, respectively. These results indicate that the fac-Ir(SFXbtz)3 is a potential phosphor for efficient orange PhOLED, possessing the advantages of low-cost, suitable doping in high concentration, and stabilized color coordinates.
2020, 78(1): 63-68
doi: 10.6023/A19110397
Abstract:
Nitrogen heterocyclic compound like imidazole and triazole are often loaded in porous material for proton conduction. Inspired by this, we employ 5, 5'-diamino-3, 3'-bis(1H-1, 2, 4-triazole) (BTDA) containing triazole fragments in the structure as the construction unit to react with 2, 4, 6-triformylphloroglucinol (TFP) through Schiff-base condensation reaction to synthesize a novel two-dimensional covalent organic framework named TFP-BTDA-COF. The theoretical results were simulated using the Accelrys Material Studios 7.0 software package and compared with the powder X-ray diffraction (PXRD) test data to confirm the crystal structure of TFP-BTDA-COF. The porosity and pore structure of TFP-BTDA-COF were characterized by N2 adsorption-desorption at 77 K. The condensation reaction was confirmed by Fourier transform infrared spectroscopy (FTIR). Due to the π-π accumulation of the 2D-COF, the N-H bond of the triazole in BTDA connecting unit is periodically and regularly arranged on each layer of the COF to form an ordered array. Under certain humidity conditions, the protons can be transmitted along the array in the one-dimensional pore channel by the intermediary of water molecules. Therefore, the TFP-BTDA-COF has the ability to conduct proton through the skeleton. The proton conductivity of TFP-BTDA-COF is tested by the AC impedance method. The results show that the proton conductivity of the material is gradually enhanced with the increase of the ambient humidity, and the maximum value is 1.4×10-3 S·cm-1 at 98% relative humidity. The PXRD of TFP-BTDA-COF in boiling water for 2 h and after 12 h AC impedance test were compared with the original experimental value to evaluate its tolerance under the working conditions of the proton membrane fuel cell. The PXRD diffraction peak intensity did not change obviously compared with that of the original experimental value. The thermogravimetric analysis results show that the thermal stability of TFP-BTDA-COF can reach high to 400℃. The above evidence proves that it has the potential to be used in proton membrane fuel cells.
Nitrogen heterocyclic compound like imidazole and triazole are often loaded in porous material for proton conduction. Inspired by this, we employ 5, 5'-diamino-3, 3'-bis(1H-1, 2, 4-triazole) (BTDA) containing triazole fragments in the structure as the construction unit to react with 2, 4, 6-triformylphloroglucinol (TFP) through Schiff-base condensation reaction to synthesize a novel two-dimensional covalent organic framework named TFP-BTDA-COF. The theoretical results were simulated using the Accelrys Material Studios 7.0 software package and compared with the powder X-ray diffraction (PXRD) test data to confirm the crystal structure of TFP-BTDA-COF. The porosity and pore structure of TFP-BTDA-COF were characterized by N2 adsorption-desorption at 77 K. The condensation reaction was confirmed by Fourier transform infrared spectroscopy (FTIR). Due to the π-π accumulation of the 2D-COF, the N-H bond of the triazole in BTDA connecting unit is periodically and regularly arranged on each layer of the COF to form an ordered array. Under certain humidity conditions, the protons can be transmitted along the array in the one-dimensional pore channel by the intermediary of water molecules. Therefore, the TFP-BTDA-COF has the ability to conduct proton through the skeleton. The proton conductivity of TFP-BTDA-COF is tested by the AC impedance method. The results show that the proton conductivity of the material is gradually enhanced with the increase of the ambient humidity, and the maximum value is 1.4×10-3 S·cm-1 at 98% relative humidity. The PXRD of TFP-BTDA-COF in boiling water for 2 h and after 12 h AC impedance test were compared with the original experimental value to evaluate its tolerance under the working conditions of the proton membrane fuel cell. The PXRD diffraction peak intensity did not change obviously compared with that of the original experimental value. The thermogravimetric analysis results show that the thermal stability of TFP-BTDA-COF can reach high to 400℃. The above evidence proves that it has the potential to be used in proton membrane fuel cells.
2020, 78(1): 69-75
doi: 10.6023/A19090329
Abstract:
High temperature proton exchange membrane fuel cells (HT-PEMFC) operated at a temperature range from 120℃ to 200℃ show high reaction kinetics, high tolerance of the Pt catalyst for impurities such as carbon monoxide and simplified water and heat management. HT-PEMFC has attracted great attentions in many applications including portable devices, unmanned vehicles and fuel cell cars. One of the essential components of the HT-PEMFC is high temperature proton exchange membrane (HT-PEM). The state-of-the-art HT-PEM is phosphoric acid (PA) doped polybenzimidazole (PBI) composite membrane. Phosphoric acid acts as the proton conductor while the PBI plays as a skeleton to hold the PA molecules and provides mechanical strength for the composite membrane. Nevertheless, the complex fabrication procedures and expensive cost hinder wide application of PBI in HT-PEMFC. Alternative polymer skeletons including polyvinylpyrrolidone and amino-functionalized proton exchange membrane have been developed for the HT-PEM. Generally, the high proton conductivity of the HT-PEMs results from high doping level of PA. However, the plasticizer effect of PA molecules reduces the Van der Waals force among the polymer macromolecules. That leads to the low mechanical strength of the HT-PEMs. Cross-linking method significantly increases the mechanical strength of the HT-PEMs. On the other hand, the cross-linking reaction consumes the PA doping site of the HT-PEMs, leading to the low proton conductivity of these HT-PEMs. In this research, a novel self-crosslinked polyethyleneimine-polysulfone (PEI-PSF) HT-PEM with both high mechanical strength and high proton conductivity has been designed. The PEI molecules are anchored to the PSF backbones by chloromethylation and tertiary aminating reactions. That is prone to enhance the mechanical strength of the membrane. In addition, the PEI also acts as PA adsorption sites, which improves the PA doping level and proton conductivity of the HT-PEM. The degree of crosslinking is controlled by the degree of chloromethylation. The 1H nuclear magnetic resonance characterization shows successfully graft of benzyl chloride onto the PSF backbone to form chloromethylated polysulfone (CMPSF). In addition, the X-ray photoelectron spectra confirm the reaction of PEI with CMPSF to form a self-crosslinked PEI-PSF membrane. With the increase of crosslinking degree, the PA doping level of the PEI-PSF membrane increases whereas its tensile strength decreases. A proton conductivity of 3.4×10-2 S·cm-1 is obtained for a PEI-PSF membrane with a chloromethylation degree of 58%, denoted as PEI-PSF-58, and PA doping level of 122 wt% at 150℃ under anhydrous conditions. Meanwhile, the PEI-PSF-58 membrane remains excellent mechanical property with tensile strength of 30 MPa at room temperature. Moreover, HT-PEMFC based on the PEI-PSF-58 membrane exhibits a high peak power density of 200 mW·cm-2 and outstanding stability under 150℃ with a constant cell voltage of 0.4 V. In summary, a series of self-crosslinked PEI-PSF HT-PEMs with both high proton conductivity and excellent mechanical properties have been synthesized. The self-crosslinking is a promising strategy to cope with trade-off between high proton conductivity and mechanical strength for the conventional PA doped HT-PEMs.
High temperature proton exchange membrane fuel cells (HT-PEMFC) operated at a temperature range from 120℃ to 200℃ show high reaction kinetics, high tolerance of the Pt catalyst for impurities such as carbon monoxide and simplified water and heat management. HT-PEMFC has attracted great attentions in many applications including portable devices, unmanned vehicles and fuel cell cars. One of the essential components of the HT-PEMFC is high temperature proton exchange membrane (HT-PEM). The state-of-the-art HT-PEM is phosphoric acid (PA) doped polybenzimidazole (PBI) composite membrane. Phosphoric acid acts as the proton conductor while the PBI plays as a skeleton to hold the PA molecules and provides mechanical strength for the composite membrane. Nevertheless, the complex fabrication procedures and expensive cost hinder wide application of PBI in HT-PEMFC. Alternative polymer skeletons including polyvinylpyrrolidone and amino-functionalized proton exchange membrane have been developed for the HT-PEM. Generally, the high proton conductivity of the HT-PEMs results from high doping level of PA. However, the plasticizer effect of PA molecules reduces the Van der Waals force among the polymer macromolecules. That leads to the low mechanical strength of the HT-PEMs. Cross-linking method significantly increases the mechanical strength of the HT-PEMs. On the other hand, the cross-linking reaction consumes the PA doping site of the HT-PEMs, leading to the low proton conductivity of these HT-PEMs. In this research, a novel self-crosslinked polyethyleneimine-polysulfone (PEI-PSF) HT-PEM with both high mechanical strength and high proton conductivity has been designed. The PEI molecules are anchored to the PSF backbones by chloromethylation and tertiary aminating reactions. That is prone to enhance the mechanical strength of the membrane. In addition, the PEI also acts as PA adsorption sites, which improves the PA doping level and proton conductivity of the HT-PEM. The degree of crosslinking is controlled by the degree of chloromethylation. The 1H nuclear magnetic resonance characterization shows successfully graft of benzyl chloride onto the PSF backbone to form chloromethylated polysulfone (CMPSF). In addition, the X-ray photoelectron spectra confirm the reaction of PEI with CMPSF to form a self-crosslinked PEI-PSF membrane. With the increase of crosslinking degree, the PA doping level of the PEI-PSF membrane increases whereas its tensile strength decreases. A proton conductivity of 3.4×10-2 S·cm-1 is obtained for a PEI-PSF membrane with a chloromethylation degree of 58%, denoted as PEI-PSF-58, and PA doping level of 122 wt% at 150℃ under anhydrous conditions. Meanwhile, the PEI-PSF-58 membrane remains excellent mechanical property with tensile strength of 30 MPa at room temperature. Moreover, HT-PEMFC based on the PEI-PSF-58 membrane exhibits a high peak power density of 200 mW·cm-2 and outstanding stability under 150℃ with a constant cell voltage of 0.4 V. In summary, a series of self-crosslinked PEI-PSF HT-PEMs with both high proton conductivity and excellent mechanical properties have been synthesized. The self-crosslinking is a promising strategy to cope with trade-off between high proton conductivity and mechanical strength for the conventional PA doped HT-PEMs.
2020, 78(1): 76-81
doi: 10.6023/A19100371
Abstract:
With the development of nanotechnology and its penetration into the field of medicine, nanotechnology has opened a new way for the treatment of tumors. Building an effective nanocarrier system is significant for the treatment of tumors. Compared with the traditional drug therapy, the drug which uses the nanomaterial as the carrier can greatly improve the treatment effect of the medicine and the side effect caused by the medicine in the in-vivo circulation process is extremely reduced simultaneously. At the same time, due to the protective effect of the carrier, the stability of the drug can be improved obviously. In this paper, we report a composite nanomaterial Bi@ZIF-8@TPZ (BZT) which is the formation of Bi nanoparticles and tirapazamine (TPZ) embedded in ZIF-8, this novel nanomaterial combines chemotherapy with photothermal therapy in the second near-infrared region (NIR-Ⅱ), and achieves a good therapeutic effect. First, we prepared a Bi@ZIF-8 (BZ) nanoparticle by a simple one-step reduction method. The morphology and microstructure of the nanoparticle were analyzed by transmission electron microscopy (TEM) and X-ray diffraction (XRD). Next, the anticancer drug tirapazamine (TPZ) was efficiently loaded into the BZ nanomaterial by physical mixing. The UV absorption spectrum proved that it could be successfully loaded, and the loading efficiency (LE) was 30%. Furthermore, the embedded Bi nanoparticles make the composite nanomaterials have good photothermal properties in NIR-Ⅱ area, and the photothermal conversion efficiency is about 31.75%. Because ZIF-8 has a good pH response ability, the material can achieve controllable drug release under weak acid (pH=5.5) and light conditions. In vitro results show that BZ loaded with the chemotherapeutic drug TPZ can achieve a good therapeutic effect. The composite materials reported in this article realize the synergistic treatment of chemotherapy and NIR-Ⅱ photothermal treatment, which makes it highly clinically useful.
With the development of nanotechnology and its penetration into the field of medicine, nanotechnology has opened a new way for the treatment of tumors. Building an effective nanocarrier system is significant for the treatment of tumors. Compared with the traditional drug therapy, the drug which uses the nanomaterial as the carrier can greatly improve the treatment effect of the medicine and the side effect caused by the medicine in the in-vivo circulation process is extremely reduced simultaneously. At the same time, due to the protective effect of the carrier, the stability of the drug can be improved obviously. In this paper, we report a composite nanomaterial Bi@ZIF-8@TPZ (BZT) which is the formation of Bi nanoparticles and tirapazamine (TPZ) embedded in ZIF-8, this novel nanomaterial combines chemotherapy with photothermal therapy in the second near-infrared region (NIR-Ⅱ), and achieves a good therapeutic effect. First, we prepared a Bi@ZIF-8 (BZ) nanoparticle by a simple one-step reduction method. The morphology and microstructure of the nanoparticle were analyzed by transmission electron microscopy (TEM) and X-ray diffraction (XRD). Next, the anticancer drug tirapazamine (TPZ) was efficiently loaded into the BZ nanomaterial by physical mixing. The UV absorption spectrum proved that it could be successfully loaded, and the loading efficiency (LE) was 30%. Furthermore, the embedded Bi nanoparticles make the composite nanomaterials have good photothermal properties in NIR-Ⅱ area, and the photothermal conversion efficiency is about 31.75%. Because ZIF-8 has a good pH response ability, the material can achieve controllable drug release under weak acid (pH=5.5) and light conditions. In vitro results show that BZ loaded with the chemotherapeutic drug TPZ can achieve a good therapeutic effect. The composite materials reported in this article realize the synergistic treatment of chemotherapy and NIR-Ⅱ photothermal treatment, which makes it highly clinically useful.
2020, 78(1): 82-88
doi: 10.6023/A19080313
Abstract:
Nitrogen doped reduced graphene oxide (N-RGO) was successfully prepared by carbon thermal reduction method, which annealed graphene oxide (GO) and cyanamide at 900℃. The 0.2% acetic acid solution with chitosan (CS) was used as the dispersant of N-RGO to improve the dispersivity, electronic mass transfer rate, and biocompatibility of N-RGO. The morphology, structure and electrochemical properties of N-RGO and CS/N-RGO were investigated by scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FT-IR), and cyclic voltammetry (CV). FT-IR spectrum indicated graphene oxide (GO) was reduced and N-RGO was successfully prepared. The electrochemical experiments demonstrated that CS/N-RGO possesses large electrochemical effective area, strong adsorptive ability and fast electronic mass transfer rate. Then a novel electrochemical sensor for detection of xanthine was fabricated based on CS/N-RGO modified glassy carbon electrode (CS/N-RGO/GCE). It exhibited good electrochemical response toward the oxidation of xanthine with a linear range covering 2.99×10-8~1.07×10-4 mol/L, and the corresponding detection limit (LOD) of 9.96×10-9 mol/L (S/N=3). In addition, the electrochemical behaviors of xanthine on CS/N-RGO/GCE were explored using cyclic voltammetry (CV), which included the pH effect on the oxidation of xanthine and the effect of scan rate on the peak current and peak potential of xanthine. Usually, uric acid in the body is generated by xanthine under the catalysis of xanthine oxidase (XOR), and high concentration of uric acid can cause gout. The inhibition for the formation of uric acid is the most direct method for the treatment of gout. Hence, the inhibition for the formation of uric acid by febuxostat and allopurinol was researched by electrochemical method, manifesting febuxostat and allopurinol can inhibit the activity of xanthine oxidase, which did not make xanthine generating uric acid. Thus, this work is very meaningful in the field of the diagnosis and treatment of gout.
Nitrogen doped reduced graphene oxide (N-RGO) was successfully prepared by carbon thermal reduction method, which annealed graphene oxide (GO) and cyanamide at 900℃. The 0.2% acetic acid solution with chitosan (CS) was used as the dispersant of N-RGO to improve the dispersivity, electronic mass transfer rate, and biocompatibility of N-RGO. The morphology, structure and electrochemical properties of N-RGO and CS/N-RGO were investigated by scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FT-IR), and cyclic voltammetry (CV). FT-IR spectrum indicated graphene oxide (GO) was reduced and N-RGO was successfully prepared. The electrochemical experiments demonstrated that CS/N-RGO possesses large electrochemical effective area, strong adsorptive ability and fast electronic mass transfer rate. Then a novel electrochemical sensor for detection of xanthine was fabricated based on CS/N-RGO modified glassy carbon electrode (CS/N-RGO/GCE). It exhibited good electrochemical response toward the oxidation of xanthine with a linear range covering 2.99×10-8~1.07×10-4 mol/L, and the corresponding detection limit (LOD) of 9.96×10-9 mol/L (S/N=3). In addition, the electrochemical behaviors of xanthine on CS/N-RGO/GCE were explored using cyclic voltammetry (CV), which included the pH effect on the oxidation of xanthine and the effect of scan rate on the peak current and peak potential of xanthine. Usually, uric acid in the body is generated by xanthine under the catalysis of xanthine oxidase (XOR), and high concentration of uric acid can cause gout. The inhibition for the formation of uric acid is the most direct method for the treatment of gout. Hence, the inhibition for the formation of uric acid by febuxostat and allopurinol was researched by electrochemical method, manifesting febuxostat and allopurinol can inhibit the activity of xanthine oxidase, which did not make xanthine generating uric acid. Thus, this work is very meaningful in the field of the diagnosis and treatment of gout.
