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2020 Volume 36 Issue 4
2020, 36(4): 585-596
doi: 10.11862/CJIC.2020.069
Abstract:
As an important bulk chemical, the annual production of propylene oxide (PO) is around ten million tons, but its industrial production methods are still suffering from severe drawbacks such as high cost, many by-products and serious pollution. In contrast, direct epoxidation of propylene with molecular O2 (DEP) has the advantages of atomic economy, environmental friendship and so on, which attracts more and more attention. However, the competing process of α-H abstraction of propylene and high activity of PO make it a grand challenge to simultaneously obtain high PO selectivity and high propylene conversion. It has been recognized that among the coinage metals, Cu-based catalysts exhibit excellent catalytic performance. The present work would summarize recent developments of Cu-based catalysts for DEP reaction. We would concentrate on how to tailor the Cu-based catalysts and pointed out some of the existing problems that need to be further studied.
As an important bulk chemical, the annual production of propylene oxide (PO) is around ten million tons, but its industrial production methods are still suffering from severe drawbacks such as high cost, many by-products and serious pollution. In contrast, direct epoxidation of propylene with molecular O2 (DEP) has the advantages of atomic economy, environmental friendship and so on, which attracts more and more attention. However, the competing process of α-H abstraction of propylene and high activity of PO make it a grand challenge to simultaneously obtain high PO selectivity and high propylene conversion. It has been recognized that among the coinage metals, Cu-based catalysts exhibit excellent catalytic performance. The present work would summarize recent developments of Cu-based catalysts for DEP reaction. We would concentrate on how to tailor the Cu-based catalysts and pointed out some of the existing problems that need to be further studied.
2020, 36(4): 597-606
doi: 10.11862/CJIC.2020.086
Abstract:
More than 50% of modern drugs used clinically come from natural products, which can prevent tumor growth and progression by influencing multiple biological pathways such as blocking cell cycle progression, inhibiting cancer cell survival signaling pathway and regulating immune cells. They also show low toxicity to normal tissues. Metal antitumor drugs represented by cisplatin have been widely used in clinical practice. However, they also have severe drug resistance and side effects, such as nephrotoxicity and neurotoxicity. Therefore, modified platinum drugs with natural products are beneficial for overcoming their deficiencies. On the other hand, the emergence of arene-metal complexes provides more possibilities for the development of high-efficiency and low-toxicity anticancer drugs due to their good water solubility and low toxicity towards normal organisms. Combining the respective advantages of natural products and metals opened up new opportunities for the development of anti-cancer drugs, and the development of metal complexes based on natural products as anticancer agents has become a research hotspot. In this paper, the research and mechanism of platinum and arene-metal complexes based on natural products are reviewed comprehensively, and the future development in this field has prospected.
More than 50% of modern drugs used clinically come from natural products, which can prevent tumor growth and progression by influencing multiple biological pathways such as blocking cell cycle progression, inhibiting cancer cell survival signaling pathway and regulating immune cells. They also show low toxicity to normal tissues. Metal antitumor drugs represented by cisplatin have been widely used in clinical practice. However, they also have severe drug resistance and side effects, such as nephrotoxicity and neurotoxicity. Therefore, modified platinum drugs with natural products are beneficial for overcoming their deficiencies. On the other hand, the emergence of arene-metal complexes provides more possibilities for the development of high-efficiency and low-toxicity anticancer drugs due to their good water solubility and low toxicity towards normal organisms. Combining the respective advantages of natural products and metals opened up new opportunities for the development of anti-cancer drugs, and the development of metal complexes based on natural products as anticancer agents has become a research hotspot. In this paper, the research and mechanism of platinum and arene-metal complexes based on natural products are reviewed comprehensively, and the future development in this field has prospected.
2020, 36(4): 607-619
doi: 10.11862/CJIC.2020.085
Abstract:
Four Dy(Ⅲ) and Zn/Ni-Dy(Ⅲ) complexes with polyamine phenol ligand were synthesized and structurally characterized, namely[Dy(CH3OCH3)L] (1), [Dy2(μ-H2O)L2] (2), [Zn2DyL2]ClO4·H2O (3) and[Ni2DyL2]ClO4·H2O (4) (H3L=N, N', N″-tris(3, 5-dimethyl-2-hydroxybenzyl)-1, 4, 7-triazacyclononane). X-ray crystallographic analysis reveals that 1 and 2 take mononuclear and binuclear structures, respectively, and both 3 and 4 take trinuclear M-Dy(Ⅲ)-M structures (M=Zn (3), Ni (4)). Magnetic measurements showed that complexes 1 and 2 exhibited field-induced slow magnetic relaxation behaviours, while 2 had multiple magnetic relaxation processes. However, no obvious slow magnetic relaxation behaviors were observed in 3 and 4. Fluorescence analyses reveal that complexes 1~3 have narrow-band characteristic emissions of Dy(Ⅲ) ions, but no significant emission was observed in 4 because of the fluorescence quenching effect of Ni(Ⅱ) ions.
Four Dy(Ⅲ) and Zn/Ni-Dy(Ⅲ) complexes with polyamine phenol ligand were synthesized and structurally characterized, namely[Dy(CH3OCH3)L] (1), [Dy2(μ-H2O)L2] (2), [Zn2DyL2]ClO4·H2O (3) and[Ni2DyL2]ClO4·H2O (4) (H3L=N, N', N″-tris(3, 5-dimethyl-2-hydroxybenzyl)-1, 4, 7-triazacyclononane). X-ray crystallographic analysis reveals that 1 and 2 take mononuclear and binuclear structures, respectively, and both 3 and 4 take trinuclear M-Dy(Ⅲ)-M structures (M=Zn (3), Ni (4)). Magnetic measurements showed that complexes 1 and 2 exhibited field-induced slow magnetic relaxation behaviours, while 2 had multiple magnetic relaxation processes. However, no obvious slow magnetic relaxation behaviors were observed in 3 and 4. Fluorescence analyses reveal that complexes 1~3 have narrow-band characteristic emissions of Dy(Ⅲ) ions, but no significant emission was observed in 4 because of the fluorescence quenching effect of Ni(Ⅱ) ions.
2020, 36(4): 620-626
doi: 10.11862/CJIC.2020.083
Abstract:
A Nasicon-type LiTi2-xMnx(PO4)3@C (x=0.02, 0.05, 0.08 and 0.1) has been successfully synthesized by a simple sol-gel method. The precipitates were annealed at 700℃ for 10 h in Ar. The metallic ion doping could increase their lattice parameters, along with the large available tunnels for Li+ diffusion, and then decrease the electrochemical resistance. The carbon layer plays an important role in improving the electronic conductivity. These composites were characterized via powder X-ray diffractometry with Cu Kα line as a radiation (λ=0.154 18 nm). The morphologies were observed by a transmission electron microscopy. The molar ratio of nMn:nTi was obtained from ICP-AES analysis. Among the samples, LiTi1.92Mn0.08(PO4)3@C exhibited the best electrochemical performance as a cathode material for lithium ion batteries, with a discharge capacity of 145 mAh·g-1 after 150 cycles at 0.1 C. It even delivered a discharge capacity of 132 mAh·g-1 in the first cycle at 5 C. This superior electrochemical property could be ascribed to its enhanced lithium-diffusion induced by doping and improved electronic conductivity induced by carbon coating.
A Nasicon-type LiTi2-xMnx(PO4)3@C (x=0.02, 0.05, 0.08 and 0.1) has been successfully synthesized by a simple sol-gel method. The precipitates were annealed at 700℃ for 10 h in Ar. The metallic ion doping could increase their lattice parameters, along with the large available tunnels for Li+ diffusion, and then decrease the electrochemical resistance. The carbon layer plays an important role in improving the electronic conductivity. These composites were characterized via powder X-ray diffractometry with Cu Kα line as a radiation (λ=0.154 18 nm). The morphologies were observed by a transmission electron microscopy. The molar ratio of nMn:nTi was obtained from ICP-AES analysis. Among the samples, LiTi1.92Mn0.08(PO4)3@C exhibited the best electrochemical performance as a cathode material for lithium ion batteries, with a discharge capacity of 145 mAh·g-1 after 150 cycles at 0.1 C. It even delivered a discharge capacity of 132 mAh·g-1 in the first cycle at 5 C. This superior electrochemical property could be ascribed to its enhanced lithium-diffusion induced by doping and improved electronic conductivity induced by carbon coating.
2020, 36(4): 627-635
doi: 10.11862/CJIC.2020.079
Abstract:
In order to solve the problems of high cost and poor stability of fuel cell cathode catalysts, Cu, N co-doped carbon based catalyst (Cu-N-KB) was prepared by simple heat treatment using α-nitroso-β-naphthol copper, melamine and conductive carbon black. The characterization results show that Cu and N are uniformly distributed in the carbon support and the copper exists in the form of crystalline copper particles and amorphous Cu-Nx. The high specific surface area and mesoporous structure of the catalyst ensure a large number of active sites and fast mass transfer efficiency. The catalyst exhibits excellent oxygen reduction catalysis, methanol resistance and stability in an alkaline medium compared to commercial Pt/C catalysts.
In order to solve the problems of high cost and poor stability of fuel cell cathode catalysts, Cu, N co-doped carbon based catalyst (Cu-N-KB) was prepared by simple heat treatment using α-nitroso-β-naphthol copper, melamine and conductive carbon black. The characterization results show that Cu and N are uniformly distributed in the carbon support and the copper exists in the form of crystalline copper particles and amorphous Cu-Nx. The high specific surface area and mesoporous structure of the catalyst ensure a large number of active sites and fast mass transfer efficiency. The catalyst exhibits excellent oxygen reduction catalysis, methanol resistance and stability in an alkaline medium compared to commercial Pt/C catalysts.
2020, 36(4): 636-642
doi: 10.11862/CJIC.2020.080
Abstract:
For the β-hydroxyethylation of sulfur atoms in thiols, there should be a strong interaction between the -SH group and the methylene carbon of ethylene carbonate (EC). However, the nucleophilicity of -SH group is insufficient to interact with the methylene carbon of EC. Therefore, a catalyst should be required to activate -SH group. Under the conditions of atmospheric pressure, solvent-free and 120℃, 14 kinds of alkali metal mineral acid salts (MA, M=Li+, Na+ and K+) were investigated for the S-hydroxyethylation of n-octyl mercaptan with EC. When A- of MA are the same, the ionic radius and polarizability of Li+, Na+ and K+ increase sequentially, the ability of MA to activate SH group also increase sequentially. The general rule is that the catalytic activity of the potassium salt is higher than that of the corresponding sodium salt, while the lithium salt has no catalytic activity. In various inorganic acid potassium salts, the catalytic activity of KA has a positive correlation with the pKa of its corresponding conjugate acid HA. The catalytic activity of KA is lower when its conjugate acid HA is more acidic. In order to explore the universality of the mechanism of potassium salt catalytic activation of -SH, K3PO4 was used as catalyst to investigate the catalytic activity of β-hydroxyethylation of six different structures of thiols with EC at different reaction temperatures. Due to the acidic difference of mercaptan, the rule is that the stronger the acidity of the mercaptan, the higher the reactivity, and the easier the S-H bond is to dissociate. The advantages of the reaction are as follows:no solvent is involved, the molar ratio of mercaptan to EC is close to the theoretical amount, the selectivity of the product β-hydroxyethyl sulfide is >99%, no halogen containing reactant involved and therefore no halogen salt byproduct is formed in the final product.
For the β-hydroxyethylation of sulfur atoms in thiols, there should be a strong interaction between the -SH group and the methylene carbon of ethylene carbonate (EC). However, the nucleophilicity of -SH group is insufficient to interact with the methylene carbon of EC. Therefore, a catalyst should be required to activate -SH group. Under the conditions of atmospheric pressure, solvent-free and 120℃, 14 kinds of alkali metal mineral acid salts (MA, M=Li+, Na+ and K+) were investigated for the S-hydroxyethylation of n-octyl mercaptan with EC. When A- of MA are the same, the ionic radius and polarizability of Li+, Na+ and K+ increase sequentially, the ability of MA to activate SH group also increase sequentially. The general rule is that the catalytic activity of the potassium salt is higher than that of the corresponding sodium salt, while the lithium salt has no catalytic activity. In various inorganic acid potassium salts, the catalytic activity of KA has a positive correlation with the pKa of its corresponding conjugate acid HA. The catalytic activity of KA is lower when its conjugate acid HA is more acidic. In order to explore the universality of the mechanism of potassium salt catalytic activation of -SH, K3PO4 was used as catalyst to investigate the catalytic activity of β-hydroxyethylation of six different structures of thiols with EC at different reaction temperatures. Due to the acidic difference of mercaptan, the rule is that the stronger the acidity of the mercaptan, the higher the reactivity, and the easier the S-H bond is to dissociate. The advantages of the reaction are as follows:no solvent is involved, the molar ratio of mercaptan to EC is close to the theoretical amount, the selectivity of the product β-hydroxyethyl sulfide is >99%, no halogen containing reactant involved and therefore no halogen salt byproduct is formed in the final product.
2020, 36(4): 643-650
doi: 10.11862/CJIC.2020.072
Abstract:
Two new metal complexes, [Mn3(Hidc)3(DMI)2]n (1) (H3idc=4, 5-imidazoledicarboxylic acid, DMI=1, 3-dimethyl-2-imidazolidinone) and[Co(tbip)(DMPU)]n (2) (H2tbip=5-tert-butylisophthalic acid, DMPU=N, N-dime-thylpropyleneurea), have been synthesized by urothermal method. The single crystal X-ray diffraction analysis shows that complex 1 exhibits a three-dimensional structure with square-shaped pores constructed by H3idc and Mn(Ⅱ), and DMI molecules are filled in the pores. Complex 2 is a two-dimensional network structure constructed by H2tbip and Co(Ⅱ) using DMPU as a template, and DMPU molecules are filled in the grids of network by coordinating with Co(Ⅱ). Solid fluorescence measurement reveals that complex 1 possesses blue fluorescence property with a strong emission at 462 nm.
Two new metal complexes, [Mn3(Hidc)3(DMI)2]n (1) (H3idc=4, 5-imidazoledicarboxylic acid, DMI=1, 3-dimethyl-2-imidazolidinone) and[Co(tbip)(DMPU)]n (2) (H2tbip=5-tert-butylisophthalic acid, DMPU=N, N-dime-thylpropyleneurea), have been synthesized by urothermal method. The single crystal X-ray diffraction analysis shows that complex 1 exhibits a three-dimensional structure with square-shaped pores constructed by H3idc and Mn(Ⅱ), and DMI molecules are filled in the pores. Complex 2 is a two-dimensional network structure constructed by H2tbip and Co(Ⅱ) using DMPU as a template, and DMPU molecules are filled in the grids of network by coordinating with Co(Ⅱ). Solid fluorescence measurement reveals that complex 1 possesses blue fluorescence property with a strong emission at 462 nm.
2020, 36(4): 651-658
doi: 10.11862/CJIC.2020.071
Abstract:
A novel tricarbonyl complex Re(CO)33(ECAF)Cl containing the bipolar (9, 9-bis(9-ethylcarbazol-3-yl)-4, 5-diazafluorene (ECAF) ligand was synthesized and characterized by NMR spectroscopy and high resolution mass spectrometry. In order to study the thermal stability and photoelectric properties of complex Re(CO)33(ECAF)Cl, the reference complex Re(CO)33(SB)Cl containing 4, 5-diazo-9, 9-spirodifluorene (SB) ligand was also synthesized. Compared with the decomposition temperature of reference (366℃), complex Re(CO)33(ECAF)Cl (419℃) exhibited better thermal stability. As a result of the increase of the optical energy gap caused by the electron-rich carbazole group, compared with the luminescence wavelength of reference complex (572 nm), the wavelength of Re(CO)33(ECAF)Cl blue-shifted to 565 nm. The luminescent quantum efficiency (39%) of Re(CO)33(ECAF)Cl was slightly higher than that of the reference material (37%). The spin-coating electroluminescent devices were fabricated, and the optimized doping concentration of Re(CO)33(ECAF)Cl-based device was as high as 30%, which was 2.4 times that of the reference complex-based device. The quite low turn-on voltage (2.9 V) of Re(CO)33(ECAF)Cl-based device was significantly less than that of reference complex-based device (4.0 V), reflecting that ECAF can depress luminescent quenching and improve the charge transporting performance of complexes significantly. The maximum current efficiency and maximum external quantum efficiency of Re(CO)33(ECAF)Cl-based devices were 8.2 cd·A-1 and 3.0%, respectively, which were lower than the efficiencies (9.7 cd·A-1 and 3.9%) of reference complex-based device. These results show that bipolar ECAF ligand is an excellent ligand for luminescent rhenium complexes.
A novel tricarbonyl complex Re(CO)33(ECAF)Cl containing the bipolar (9, 9-bis(9-ethylcarbazol-3-yl)-4, 5-diazafluorene (ECAF) ligand was synthesized and characterized by NMR spectroscopy and high resolution mass spectrometry. In order to study the thermal stability and photoelectric properties of complex Re(CO)33(ECAF)Cl, the reference complex Re(CO)33(SB)Cl containing 4, 5-diazo-9, 9-spirodifluorene (SB) ligand was also synthesized. Compared with the decomposition temperature of reference (366℃), complex Re(CO)33(ECAF)Cl (419℃) exhibited better thermal stability. As a result of the increase of the optical energy gap caused by the electron-rich carbazole group, compared with the luminescence wavelength of reference complex (572 nm), the wavelength of Re(CO)33(ECAF)Cl blue-shifted to 565 nm. The luminescent quantum efficiency (39%) of Re(CO)33(ECAF)Cl was slightly higher than that of the reference material (37%). The spin-coating electroluminescent devices were fabricated, and the optimized doping concentration of Re(CO)33(ECAF)Cl-based device was as high as 30%, which was 2.4 times that of the reference complex-based device. The quite low turn-on voltage (2.9 V) of Re(CO)33(ECAF)Cl-based device was significantly less than that of reference complex-based device (4.0 V), reflecting that ECAF can depress luminescent quenching and improve the charge transporting performance of complexes significantly. The maximum current efficiency and maximum external quantum efficiency of Re(CO)33(ECAF)Cl-based devices were 8.2 cd·A-1 and 3.0%, respectively, which were lower than the efficiencies (9.7 cd·A-1 and 3.9%) of reference complex-based device. These results show that bipolar ECAF ligand is an excellent ligand for luminescent rhenium complexes.
2020, 36(4): 659-665
doi: 10.11862/CJIC.2020.066
Abstract:
Quantum spin liquids are the third type of magnetism that has just been confirmed in recent years besides ferromagnets and antiferromagnets. They have attracted much attention in the fields of physics and materials because they are expected to explain the mechanism of high temperature superconductors and to change the storage mode of computer hard disk information. Spin frustration, as the smallest unit of quantum spin liquids, may be the key to solve many problems of quantum spin liquids. Based on the reported three-nuclear copper complexes, [Cu3(μ3-OH)(μ-OPz)3(NO3)2(H2O)2]·CH3OH (1) (HOPz=methyl(2-pyrazinyl)ketone oxime), we synthesized a three-dimensional metal-organic framework (MOF), {[Ag(HOPz)Cu3(μ3-OH)(NO3)3(OPz)2Ag(NO3)]·6H2O]}n (2). Their magnetic properties were analyzed in detail from the perspective of spin frustration by comparison. The magnetic studies indicate that there exists a strong antiferromagnetic interactions between spins and antisymmetric exchanges. The magnetic data are fitted and the magnetostructural correlation is studied by Hamiltonian containing isotropic and antisymmetric exchanges. The best fitting parameters obtained are:Jav=-426 cm-1, g⊥=1.83, g//=2.00 for 1 and Jav=-401 cm-1, g⊥=1.85, g//=2.00 for 2.
Quantum spin liquids are the third type of magnetism that has just been confirmed in recent years besides ferromagnets and antiferromagnets. They have attracted much attention in the fields of physics and materials because they are expected to explain the mechanism of high temperature superconductors and to change the storage mode of computer hard disk information. Spin frustration, as the smallest unit of quantum spin liquids, may be the key to solve many problems of quantum spin liquids. Based on the reported three-nuclear copper complexes, [Cu3(μ3-OH)(μ-OPz)3(NO3)2(H2O)2]·CH3OH (1) (HOPz=methyl(2-pyrazinyl)ketone oxime), we synthesized a three-dimensional metal-organic framework (MOF), {[Ag(HOPz)Cu3(μ3-OH)(NO3)3(OPz)2Ag(NO3)]·6H2O]}n (2). Their magnetic properties were analyzed in detail from the perspective of spin frustration by comparison. The magnetic studies indicate that there exists a strong antiferromagnetic interactions between spins and antisymmetric exchanges. The magnetic data are fitted and the magnetostructural correlation is studied by Hamiltonian containing isotropic and antisymmetric exchanges. The best fitting parameters obtained are:Jav=-426 cm-1, g⊥=1.83, g//=2.00 for 1 and Jav=-401 cm-1, g⊥=1.85, g//=2.00 for 2.
2020, 36(4): 666-672
doi: 10.11862/CJIC.2020.077
Abstract:
Metal string complexes, with the structure of linear metal chain helically wrapped by four equatorial ligands, have attracted extensively attention due to their unique electronic, magnetic, and potential applications in molecular electronics. Some factors such as difference of metal atoms, axial ligands and equatorial ligands would affect the physical properties of conductance and magnetic properties of metal string complexes. The diversity of equatorial ligands provides more possibilities for such changes. The coordination structures of metal string complexes[MoMoCo(npo)4(NCS)2] (npo=1, 8-naphthyl-2-ketone) with potential applications as molecular wires have been investigated using the density functional theory B3LYP method by considering the effects of an external electric field (EF). The coordination mode is denoted as (n, m), where n and m represent the number of oxygen atoms coordinated with the Co3 and Mo1, respectively, and n=0, 1, 2, 3, 4; m=4, 3, 2, 1, 0. The energies and polarities of these molecules increase gradually as the coordination modes of four npo- ligands become more and more consistent, but all of them can exist stably and compete with each other. The Mo-Mo quadruple bond exists in all molecules, and the bond length decreases with the decrease of the Z-direction dipole moment μ(Z). In addition, as the value of μ(Z) decreases, the orbital energy of πNCS*(1) decreases but that of πNCS*(2) increases. The geometric and electronic structures of the five coordination modes change regularly under the action of electric field. Under the electric field effect of Z direction, the Mo1-N8 bond lengths of all coordination modes except (0, 4) increase obviously, leading to structural instability. Moreover, the phenomenons of energy level interlacing in the frontier orbitals, and the reduction of LUMO-HOMO energy gap are related to the value of μ(Z). When μ(Z) is positive, the energy gaps of (0, 4) and (1, 3) decrease more significantly under the electric field effect of -Z direction. However, when μ(Z) is negative, the energy gaps of (2, 2), (3, 1) and (4, 0) decrease more obviously under the electric field effect of Z direction. Therefore, the complexes of (0, 4), (3, 1) and (4, 0) may have the rectification effect, but (3, 1) and (4, 0) are less stable.
Metal string complexes, with the structure of linear metal chain helically wrapped by four equatorial ligands, have attracted extensively attention due to their unique electronic, magnetic, and potential applications in molecular electronics. Some factors such as difference of metal atoms, axial ligands and equatorial ligands would affect the physical properties of conductance and magnetic properties of metal string complexes. The diversity of equatorial ligands provides more possibilities for such changes. The coordination structures of metal string complexes[MoMoCo(npo)4(NCS)2] (npo=1, 8-naphthyl-2-ketone) with potential applications as molecular wires have been investigated using the density functional theory B3LYP method by considering the effects of an external electric field (EF). The coordination mode is denoted as (n, m), where n and m represent the number of oxygen atoms coordinated with the Co3 and Mo1, respectively, and n=0, 1, 2, 3, 4; m=4, 3, 2, 1, 0. The energies and polarities of these molecules increase gradually as the coordination modes of four npo- ligands become more and more consistent, but all of them can exist stably and compete with each other. The Mo-Mo quadruple bond exists in all molecules, and the bond length decreases with the decrease of the Z-direction dipole moment μ(Z). In addition, as the value of μ(Z) decreases, the orbital energy of πNCS*(1) decreases but that of πNCS*(2) increases. The geometric and electronic structures of the five coordination modes change regularly under the action of electric field. Under the electric field effect of Z direction, the Mo1-N8 bond lengths of all coordination modes except (0, 4) increase obviously, leading to structural instability. Moreover, the phenomenons of energy level interlacing in the frontier orbitals, and the reduction of LUMO-HOMO energy gap are related to the value of μ(Z). When μ(Z) is positive, the energy gaps of (0, 4) and (1, 3) decrease more significantly under the electric field effect of -Z direction. However, when μ(Z) is negative, the energy gaps of (2, 2), (3, 1) and (4, 0) decrease more obviously under the electric field effect of Z direction. Therefore, the complexes of (0, 4), (3, 1) and (4, 0) may have the rectification effect, but (3, 1) and (4, 0) are less stable.
2020, 36(4): 673-680
doi: 10.11862/CJIC.2020.088
Abstract:
Nano-NiO was prepared by hydrothermal synthesis and cross-linked with multi-walled carbon nanotubes (MWCNTs) and aramid paper (AP) to form a novel composite interlayer (NMAP). The NMAP interlayer has a three-dimensional porous structure, which not only reduces the loss of active materials, but also captures soluble polysulfides; NMAP material has strong chemical adsorption capacity for adsorbing polysulfide. The morphology and structure of the composite interlayer were observed by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD). The electrochemical test results showed that the first discharge capacity of electrode with NMAP interlayer reached 1 437 mAh·g-1 at a rate of 0.05C, and the utilization rate of active material was as high as 85.8%. The specific discharge capacity still reached 668 mAh·g-1 at 4C, and the coulomb efficiency remained at 99.1%, showing excellent magnification and cycling performance.
Nano-NiO was prepared by hydrothermal synthesis and cross-linked with multi-walled carbon nanotubes (MWCNTs) and aramid paper (AP) to form a novel composite interlayer (NMAP). The NMAP interlayer has a three-dimensional porous structure, which not only reduces the loss of active materials, but also captures soluble polysulfides; NMAP material has strong chemical adsorption capacity for adsorbing polysulfide. The morphology and structure of the composite interlayer were observed by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD). The electrochemical test results showed that the first discharge capacity of electrode with NMAP interlayer reached 1 437 mAh·g-1 at a rate of 0.05C, and the utilization rate of active material was as high as 85.8%. The specific discharge capacity still reached 668 mAh·g-1 at 4C, and the coulomb efficiency remained at 99.1%, showing excellent magnification and cycling performance.
2020, 36(4): 681-687
doi: 10.11862/CJIC.2020.053
Abstract:
Carbon-coated Ni3S4 nanoparticles supported on the surface of carbon nanofibers (Ni3S4@C/CNFs) was synthesized by electrospinning and hydrothermal methods. Then, the Ni3S4@C/CNFs counter electrode with film thickness of 2, 4, 6, 7, 8, 9, 10 μm were prepared by spraying method, and applied to dye-sensitized solar cells (DSSCs). The effect of Ni3S4@C/CNFs electrode film thickness on the photovoltaic performance of DSSCs was investigated. If the thickness of the counter electrode was too small, there were not enough catalytically active sites to reduce I3-. However, if the thickness of the counter electrode was too large, the connectivity of the counter electrode film may be deteriorated, and the electron transmission distance may be increased. Therefore, the resistance increased, and the recombination probability of the electron also increased. According to the results, when the Ni3S4@C/CNFs counter electrode film thickness was 9 μm, DSSCs achieved the highest photoelectric conversion efficiency (PCE) of 8.45%.
Carbon-coated Ni3S4 nanoparticles supported on the surface of carbon nanofibers (Ni3S4@C/CNFs) was synthesized by electrospinning and hydrothermal methods. Then, the Ni3S4@C/CNFs counter electrode with film thickness of 2, 4, 6, 7, 8, 9, 10 μm were prepared by spraying method, and applied to dye-sensitized solar cells (DSSCs). The effect of Ni3S4@C/CNFs electrode film thickness on the photovoltaic performance of DSSCs was investigated. If the thickness of the counter electrode was too small, there were not enough catalytically active sites to reduce I3-. However, if the thickness of the counter electrode was too large, the connectivity of the counter electrode film may be deteriorated, and the electron transmission distance may be increased. Therefore, the resistance increased, and the recombination probability of the electron also increased. According to the results, when the Ni3S4@C/CNFs counter electrode film thickness was 9 μm, DSSCs achieved the highest photoelectric conversion efficiency (PCE) of 8.45%.
2020, 36(4): 688-694
doi: 10.11862/CJIC.2020.075
Abstract:
MgAl2O4:Er3+, Yb3+ upconversion phosphors was prepared by low-temperature hydrothermal method combined with calcination process and using urea as precipitant. The crystal structure, morphology and upconversion luminescence properties of the samples were investigated. The results show that the main morphology of the product changed from hexagonal flake structure to nanorod-like structure with the increase of urea content. Pure phase of Mg-Al spinel structure can be obtained after calcinating at 1 100℃. Er3+ and Yb3+ can enter into MgAl2O4 lattice effectively and occupy Mg2+ sites to form homogeneous solid solution. MgAl2O4:1.0%(n/n)Er3+, x%(n/n)Yb3+ (x=0~8.0) phosphors show green (524 and 545 nm) and strong red (658 nm) light emission under 980 nm laser diode excitation, the red and green light intensity reached the maximum at 5.0%(n/n)Yb3+ doping, but the intensity ratio of red light vs green light reached the maximum value of 5.2 at 7.0%(n/n)Yb3+ doping, which is attributed to the major role of cross relaxation (CR) between Er3+ and Er3+ in red light emission process. The color-tunable of yellow-green light can be realized basically by adjusting the doping content of Yb3+ in the phosphor.
MgAl2O4:Er3+, Yb3+ upconversion phosphors was prepared by low-temperature hydrothermal method combined with calcination process and using urea as precipitant. The crystal structure, morphology and upconversion luminescence properties of the samples were investigated. The results show that the main morphology of the product changed from hexagonal flake structure to nanorod-like structure with the increase of urea content. Pure phase of Mg-Al spinel structure can be obtained after calcinating at 1 100℃. Er3+ and Yb3+ can enter into MgAl2O4 lattice effectively and occupy Mg2+ sites to form homogeneous solid solution. MgAl2O4:1.0%(n/n)Er3+, x%(n/n)Yb3+ (x=0~8.0) phosphors show green (524 and 545 nm) and strong red (658 nm) light emission under 980 nm laser diode excitation, the red and green light intensity reached the maximum at 5.0%(n/n)Yb3+ doping, but the intensity ratio of red light vs green light reached the maximum value of 5.2 at 7.0%(n/n)Yb3+ doping, which is attributed to the major role of cross relaxation (CR) between Er3+ and Er3+ in red light emission process. The color-tunable of yellow-green light can be realized basically by adjusting the doping content of Yb3+ in the phosphor.
2020, 36(4): 695-702
doi: 10.11862/CJIC.2020.068
Abstract:
Sulfur-infused CuS hollow nanospheres (denoted as CuS@S HSs) were synthesized through a facile sublimation method. Compared to pure CuS hollow nanospheres, the sulfur-infused CuS nanospheres exhibited better enrichment performance toward Hg2+, one of the most toxic heavy metal pollutants in the aquatic environment. Under an optimal sulfur mass loading of wS/wCuS=30%, CuS@S HSs exhibited a super mercury adsorption capacity of 1 207 mg·g-1, 229% higher than that without sulfur-infusion. Additionally, CuS@S HSs demonstrated highly rapid removal of Hg2+, over 99% of Hg2+ could be captured just within 3 min. Besides, CuS@S HSs captured Hg2+ selectively among other toxic heavy metal ions such as Pb2+, Ni2+, Cd2+, and Cr3+.
Sulfur-infused CuS hollow nanospheres (denoted as CuS@S HSs) were synthesized through a facile sublimation method. Compared to pure CuS hollow nanospheres, the sulfur-infused CuS nanospheres exhibited better enrichment performance toward Hg2+, one of the most toxic heavy metal pollutants in the aquatic environment. Under an optimal sulfur mass loading of wS/wCuS=30%, CuS@S HSs exhibited a super mercury adsorption capacity of 1 207 mg·g-1, 229% higher than that without sulfur-infusion. Additionally, CuS@S HSs demonstrated highly rapid removal of Hg2+, over 99% of Hg2+ could be captured just within 3 min. Besides, CuS@S HSs captured Hg2+ selectively among other toxic heavy metal ions such as Pb2+, Ni2+, Cd2+, and Cr3+.
2020, 36(4): 703-714
doi: 10.11862/CJIC.2020.082
Abstract:
Herein, we report quadruple-hierarchy micro-nano structured nickel-copper alloy electrocatalysts with phase-separated metallic Ni and Cu as the main crystal phase, which were grown in situ on nickel mesh (NM) substrate by hydrogen bubble-template method. During hybrid water electrolysis, NiCu/NM electrode only requires hydrogen evolution reaction (HER) overpotential and hydrazine oxidation (HzOR) potential of 104 and 41 mV to afford 10 mA·cm-2, respectively, in 1 mol·L-1 KOH containing 0.5 mol·L-1 N2H4·H2O. Integrated into a hybrid cell, the NiCu/NM couple require a cell voltage of only 0.536 V to deliver a current density of 100 mA·cm-2, far lower than that of overall water splitting (1.921 V), giving rise to the great improvement of hydrogen-producing efficiency. Whether in three-electrode or two-electrode devices, the as-obtained catalyst displays superior electrocatalytic activity and stability towards HER or HzOR. The remarkable catalytic performance is attributed to two key factors. On the one hand, multiple-hierarchy structured NiCu alloy films with 14-fold increased ECSA expose huge number of catalytic active sites and present sufficient channels for charge transfer and material transfer on the electrode surface in both HER and HzOR. On the other hand, the strong synergistic effect induced by Cu-doping brings great improvement of intrinsic HER activity of electrode materials. The both factors contribute collectively to the superior electrocatalytic performances of NiCu/NM during hybrid water splitting, and the structural advantages of the unique 3D hierarchical porous macro-nano structures are the dominant factors.
Herein, we report quadruple-hierarchy micro-nano structured nickel-copper alloy electrocatalysts with phase-separated metallic Ni and Cu as the main crystal phase, which were grown in situ on nickel mesh (NM) substrate by hydrogen bubble-template method. During hybrid water electrolysis, NiCu/NM electrode only requires hydrogen evolution reaction (HER) overpotential and hydrazine oxidation (HzOR) potential of 104 and 41 mV to afford 10 mA·cm-2, respectively, in 1 mol·L-1 KOH containing 0.5 mol·L-1 N2H4·H2O. Integrated into a hybrid cell, the NiCu/NM couple require a cell voltage of only 0.536 V to deliver a current density of 100 mA·cm-2, far lower than that of overall water splitting (1.921 V), giving rise to the great improvement of hydrogen-producing efficiency. Whether in three-electrode or two-electrode devices, the as-obtained catalyst displays superior electrocatalytic activity and stability towards HER or HzOR. The remarkable catalytic performance is attributed to two key factors. On the one hand, multiple-hierarchy structured NiCu alloy films with 14-fold increased ECSA expose huge number of catalytic active sites and present sufficient channels for charge transfer and material transfer on the electrode surface in both HER and HzOR. On the other hand, the strong synergistic effect induced by Cu-doping brings great improvement of intrinsic HER activity of electrode materials. The both factors contribute collectively to the superior electrocatalytic performances of NiCu/NM during hybrid water splitting, and the structural advantages of the unique 3D hierarchical porous macro-nano structures are the dominant factors.
2020, 36(4): 730-736
doi: 10.11862/CJIC.2020.076
Abstract:
Two coordination polymers, {[Co(bib)3](ClO4)2}n (1) and {[Cu3(bix)4.5](ClO4)3}n (2), (bib=1, 4-bis(imidazol-1-yl)-butane, bix=1, 4-bis(imidazol-1-ylmethyl)benzene) have been hydrothermally synthesized by using Co(ClO4)2·6H2O/Cu(ClO4)·6H2O, 1, 4-bis(imidazolyl-1-yl)butane/1, 4-bis(imidazolyl-1-yl) benzene and 4, 4'-(1, 3-phenylenebis(methyleneoxy))dibenzoic acid (H2pmda) as raw materials and structurally characterized by elemental analysis, IR spectrum, fluorescence spectrum, single-crystal and powder X-ray diffraction. Complex 1 crystallizes in trigonal system, space group R\begin{document}$\bar 3$\end{document} \begin{document}$\bar 3$\end{document}
Two coordination polymers, {[Co(bib)3](ClO4)2}n (1) and {[Cu3(bix)4.5](ClO4)3}n (2), (bib=1, 4-bis(imidazol-1-yl)-butane, bix=1, 4-bis(imidazol-1-ylmethyl)benzene) have been hydrothermally synthesized by using Co(ClO4)2·6H2O/Cu(ClO4)·6H2O, 1, 4-bis(imidazolyl-1-yl)butane/1, 4-bis(imidazolyl-1-yl) benzene and 4, 4'-(1, 3-phenylenebis(methyleneoxy))dibenzoic acid (H2pmda) as raw materials and structurally characterized by elemental analysis, IR spectrum, fluorescence spectrum, single-crystal and powder X-ray diffraction. Complex 1 crystallizes in trigonal system, space group R
2020, 36(4): 737-746
doi: 10.11862/CJIC.2020.078
Abstract:
Both amorphous and crystalline FeCeOx/SiO2 solid base catalysts were prepared by chemical reduction and co-precipitation methods, respectively. The activity of amorphous FeCeOx/SiO2 for the transesterification of prenyl acetate with methanol was remarkably enhanced compared with crystalline FeCeOx/SiO2. The catalysts were characterized by inductively coupled plasma mass spectrometry(ICP-MS), N2 adsorption-desorption, transmission electron microscopy (TEM) in combination with selected area electron diffraction (SAED), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and temperature programmed desorption (CO2-TPD and NH3-TPD). As a result, the activity of the catalysts is found to be closely related to its basicity, and the amorphous FeCeOx/SiO2 shows higher basicity. Prenyl acetate conversion of 95% and prenyl alcohol selectivity of 96% were obtained using amorphous FeCeOx/SiO2 catalyst in transesterification reaction at 130℃ for 10 h. The catalyst maintained a high level of activity after 10 cycles of testing. X-ray diffraction analyses of fresh and used FeCeOx/SiO2 catalyst demonstrated that this catalyst is exceptionally stable, which could be of value in industrial application related to heterogeneous catalytic transesterification.
Both amorphous and crystalline FeCeOx/SiO2 solid base catalysts were prepared by chemical reduction and co-precipitation methods, respectively. The activity of amorphous FeCeOx/SiO2 for the transesterification of prenyl acetate with methanol was remarkably enhanced compared with crystalline FeCeOx/SiO2. The catalysts were characterized by inductively coupled plasma mass spectrometry(ICP-MS), N2 adsorption-desorption, transmission electron microscopy (TEM) in combination with selected area electron diffraction (SAED), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and temperature programmed desorption (CO2-TPD and NH3-TPD). As a result, the activity of the catalysts is found to be closely related to its basicity, and the amorphous FeCeOx/SiO2 shows higher basicity. Prenyl acetate conversion of 95% and prenyl alcohol selectivity of 96% were obtained using amorphous FeCeOx/SiO2 catalyst in transesterification reaction at 130℃ for 10 h. The catalyst maintained a high level of activity after 10 cycles of testing. X-ray diffraction analyses of fresh and used FeCeOx/SiO2 catalyst demonstrated that this catalyst is exceptionally stable, which could be of value in industrial application related to heterogeneous catalytic transesterification.
2020, 36(4): 747-754
doi: 10.11862/CJIC.2020.084
Abstract:
Hydroxyapatite nanotubes (HAP NTs) were synthesized by a facile method, which were 20~40 nm in length and had a large surface area of 56 m2·g-1. Then the prepared HAP NTs were employed to immobilize Pb2+, Cd2+, Cu2+, Co2+, Ni2+, Zn2+, and Hg2+ in aqueous solution and the as-prepared HAP NTs showed a high immobilization capacity. In addition, the desorption rate of the prepared HAP NTs on seven heavy metal ions were all less than 1%, which showed a strong stability. The experimental data was analyzed by the Langmuir and Freundlich isotherm models. The obtained results from the application of the two equations showed that the adsorption equilibrium was best fitted with a Langmuir model and monolayer adsorption capacity was 958.28 mg·g-1, which showed a perfect immobilization property. The adsorption mechanisms were further studied by energy dispersive X-ray spectrum (EDS) and X-ray diffraction (XRD) patterns and the results showed that the adsorption mechanism was the dissolution of HAP NTs and the precipitation of a more stable Pb5(PO4)3(OH) when the amount of Pb2+ ions in solution was sufficient. Our study confirmed the possibilities of using HAP NTs to treat Pb-contaminated wastewater in the environmental pollution management.
Hydroxyapatite nanotubes (HAP NTs) were synthesized by a facile method, which were 20~40 nm in length and had a large surface area of 56 m2·g-1. Then the prepared HAP NTs were employed to immobilize Pb2+, Cd2+, Cu2+, Co2+, Ni2+, Zn2+, and Hg2+ in aqueous solution and the as-prepared HAP NTs showed a high immobilization capacity. In addition, the desorption rate of the prepared HAP NTs on seven heavy metal ions were all less than 1%, which showed a strong stability. The experimental data was analyzed by the Langmuir and Freundlich isotherm models. The obtained results from the application of the two equations showed that the adsorption equilibrium was best fitted with a Langmuir model and monolayer adsorption capacity was 958.28 mg·g-1, which showed a perfect immobilization property. The adsorption mechanisms were further studied by energy dispersive X-ray spectrum (EDS) and X-ray diffraction (XRD) patterns and the results showed that the adsorption mechanism was the dissolution of HAP NTs and the precipitation of a more stable Pb5(PO4)3(OH) when the amount of Pb2+ ions in solution was sufficient. Our study confirmed the possibilities of using HAP NTs to treat Pb-contaminated wastewater in the environmental pollution management.
2020, 36(4): 755-761
doi: 10.11862/CJIC.2020.089
Abstract:
Four triorganotin 1, 1'-methylenebis(1H-pyrazole-4-carboxylates) (CH2(PzCO2SnR3)2, R=Ph (1), cyclohexyl (2), Et (3), n-Bu (4)) have been synthesized via the reaction of R3SnOH or (R3Sn)2O with 1, 1'-methylenebis(1H-pyrazole-4-carboxylic acid). All these complexes were characterized by elemental analysis, IR and multinuclear NMR (1H, 13C and 119Sn). The structures of 1 and 3 have been confirmed by the X-ray single crystal diffraction analysis, suggesting that the pyrazoyl nitrogen atoms don't participate in coordination to the tin atoms, and the carboxylate groups show considerably different coordination modes in these two complexes. In addition, complex 1 only shows a dinuclear structure, while complex 3 forms a 2D-coordination polymer with 32-membered macrocyclic units through the bridging carboxylate oxygen atoms. The cytotoxic activity of these complexes for MCF-7 and A549 cells was tested, showing that they displayed good cytotoxicities for these two cells in vitro.CCDC: 1949278, 1; 1949279, 3.
Four triorganotin 1, 1'-methylenebis(1H-pyrazole-4-carboxylates) (CH2(PzCO2SnR3)2, R=Ph (1), cyclohexyl (2), Et (3), n-Bu (4)) have been synthesized via the reaction of R3SnOH or (R3Sn)2O with 1, 1'-methylenebis(1H-pyrazole-4-carboxylic acid). All these complexes were characterized by elemental analysis, IR and multinuclear NMR (1H, 13C and 119Sn). The structures of 1 and 3 have been confirmed by the X-ray single crystal diffraction analysis, suggesting that the pyrazoyl nitrogen atoms don't participate in coordination to the tin atoms, and the carboxylate groups show considerably different coordination modes in these two complexes. In addition, complex 1 only shows a dinuclear structure, while complex 3 forms a 2D-coordination polymer with 32-membered macrocyclic units through the bridging carboxylate oxygen atoms. The cytotoxic activity of these complexes for MCF-7 and A549 cells was tested, showing that they displayed good cytotoxicities for these two cells in vitro.CCDC: 1949278, 1; 1949279, 3.
2020, 36(4): 762-768
doi: 10.11862/CJIC.2020.087
Abstract:
A benzimidazole-based fluorescent turn-on probe (FP1) for the detection of HSO3- has been synthesized and characterized. The results showed that FP1 exhibited a clear off-on fluorescence response toward HSO3-, and it was highly selective and sensitive to HSO3- with strong anti-interference and a short response time (2 min). The fluorescence intensity of FP1 varied linearly with the concentration of HSO3- in the range of 1.2~8.1 μmol·L-1, and the detection limit for HSO3- was estimated to be 0.14 μmol·L-1. In addition, FP1 can be used to detect HSO3- in real samples with good recovery, and it was also applicable for fluorescence imaging of HSO3- in living HeLa cells.
A benzimidazole-based fluorescent turn-on probe (FP1) for the detection of HSO3- has been synthesized and characterized. The results showed that FP1 exhibited a clear off-on fluorescence response toward HSO3-, and it was highly selective and sensitive to HSO3- with strong anti-interference and a short response time (2 min). The fluorescence intensity of FP1 varied linearly with the concentration of HSO3- in the range of 1.2~8.1 μmol·L-1, and the detection limit for HSO3- was estimated to be 0.14 μmol·L-1. In addition, FP1 can be used to detect HSO3- in real samples with good recovery, and it was also applicable for fluorescence imaging of HSO3- in living HeLa cells.
2020, 36(4): 769-776
doi: 10.11862/CJIC.2020.070
Abstract:
Ordered mesoporous carbon CMK-3 was synthesized via the nanocasting route, and used to prepare Cu/CMK-3 catalyst for dimethyl carbonate (DMC) synthesis by oxidative carbonylation of methanol in a gas-phase reaction. The effect of activation temperature on the catalyst structure and catalytic performance were investigated. N2 adsorption-desorption, X-ray diffraction (XRD) and transmission electron microscopy (TEM) results revealed that the Cu/CMK-3 catalysts were mesoporous, the active copper species dispersed well in the surface and pore channels of CMK-3, their diameter were between 10~20 nm, far less than that of Cu/activated carbon (Cu/AC). The corresponding catalytic activity in a fixed-bed reactor increased with the activation temperature and the Cu/CMK-3 catalyst prepared at 450℃ exhibited the best catalytic activity. The space time yield (STY) was 286 mg·g-1·h-1 and the selectivity for DMC was 76% in 10 h running. A long periodic test also confirmed a better catalytic stability of Cu/CMK-3 compared to Cu/AC, the STY of DMC declined by 20% after 50 h reaction and 28% after 75 h reaction.
Ordered mesoporous carbon CMK-3 was synthesized via the nanocasting route, and used to prepare Cu/CMK-3 catalyst for dimethyl carbonate (DMC) synthesis by oxidative carbonylation of methanol in a gas-phase reaction. The effect of activation temperature on the catalyst structure and catalytic performance were investigated. N2 adsorption-desorption, X-ray diffraction (XRD) and transmission electron microscopy (TEM) results revealed that the Cu/CMK-3 catalysts were mesoporous, the active copper species dispersed well in the surface and pore channels of CMK-3, their diameter were between 10~20 nm, far less than that of Cu/activated carbon (Cu/AC). The corresponding catalytic activity in a fixed-bed reactor increased with the activation temperature and the Cu/CMK-3 catalyst prepared at 450℃ exhibited the best catalytic activity. The space time yield (STY) was 286 mg·g-1·h-1 and the selectivity for DMC was 76% in 10 h running. A long periodic test also confirmed a better catalytic stability of Cu/CMK-3 compared to Cu/AC, the STY of DMC declined by 20% after 50 h reaction and 28% after 75 h reaction.
2020, 36(4): 715-729
doi: 10.11862/CJIC.2020.081
Abstract:
CdS@DMSA-GO composites have been synthesized by introducing meso-2, 3-dimercaptosuccinic acid (DMSA) into grapheme oxide to construct three-dimensional architecture. The experimental results indicate that the temperature has an important influence on the structure and properties of the as-prepared materials. CdS@DMSA-G-100℃ exhibited the best adsorption ability and photocatalytic activity for the degradation of rhodamine B (RhB) and Congo Red (CR). The degradation rate reached over 96%. The radical trapping test illuminate that ·O2 radical was the dominant active oxygen species in the photocatalytic process.
CdS@DMSA-GO composites have been synthesized by introducing meso-2, 3-dimercaptosuccinic acid (DMSA) into grapheme oxide to construct three-dimensional architecture. The experimental results indicate that the temperature has an important influence on the structure and properties of the as-prepared materials. CdS@DMSA-G-100℃ exhibited the best adsorption ability and photocatalytic activity for the degradation of rhodamine B (RhB) and Congo Red (CR). The degradation rate reached over 96%. The radical trapping test illuminate that ·O2 radical was the dominant active oxygen species in the photocatalytic process.
