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2020 Volume 36 Issue 9
2020, 36(9): 1613-1619
doi: 10.11862/CJIC.2020.196
Abstract:
2-Picolinic acid (2-PA) has been integrated with Keggin-type[SiW12O40]4- and[PMo12O40]3- polyoxometalates units to achieve final products:H2[(CH3)4N]6[Cu(2-PA)2(SiW12O40)2] (1) and (H3O)[Cu6(2-PA)9(PMo12O40)(NO3)] (2). These two inorganic-organic hybrid compounds have been characterized by single-crystal X-ray diffraction, infrared spectroscopy and powder X-ray diffraction. Compound 1 crystalizes in monoclinic system with space group P21/c, and the asymmetric unit is composed of one Cu(Ⅱ) ion, two 2-PA ligands and two[SiW12O40]4- Keggin-type polyoxometalate anions. Compound 1 is a zero-dimensional structure. The cyclic voltammogram of 1-CPE(the bulk-modified carbon paste electrode) showed that the half-wave potentials (E1/2=(Ecp+Eap)/2) of Ⅰ-Ⅰ', Ⅱ-Ⅱ' and Ⅲ-Ⅲ' were -270, -516 and -708 mV, respectively, when the sweep speed was 100 mV·s-1. Compound 2 crystallizes in trigonal system with space group R3c, there are two crystallographically independent Cu ions with two kinds of coordination modes in 2 and it is a two-dimensional networks containing hexanuclear clusters.
2-Picolinic acid (2-PA) has been integrated with Keggin-type[SiW12O40]4- and[PMo12O40]3- polyoxometalates units to achieve final products:H2[(CH3)4N]6[Cu(2-PA)2(SiW12O40)2] (1) and (H3O)[Cu6(2-PA)9(PMo12O40)(NO3)] (2). These two inorganic-organic hybrid compounds have been characterized by single-crystal X-ray diffraction, infrared spectroscopy and powder X-ray diffraction. Compound 1 crystalizes in monoclinic system with space group P21/c, and the asymmetric unit is composed of one Cu(Ⅱ) ion, two 2-PA ligands and two[SiW12O40]4- Keggin-type polyoxometalate anions. Compound 1 is a zero-dimensional structure. The cyclic voltammogram of 1-CPE(the bulk-modified carbon paste electrode) showed that the half-wave potentials (E1/2=(Ecp+Eap)/2) of Ⅰ-Ⅰ', Ⅱ-Ⅱ' and Ⅲ-Ⅲ' were -270, -516 and -708 mV, respectively, when the sweep speed was 100 mV·s-1. Compound 2 crystallizes in trigonal system with space group R3c, there are two crystallographically independent Cu ions with two kinds of coordination modes in 2 and it is a two-dimensional networks containing hexanuclear clusters.
2020, 36(9): 1728-1734
doi: 10.11862/CJIC.2020.181
Abstract:
Two 1D cadmium(Ⅱ) coordination polymers, namely[Cd2(μ5-L)(phen)2]n (1) and {[Cd2(μ4-L)(2, 2'-bipy)2 (H2O)2]·2H2O}n (2), have been constructed hydrothermally using H4L (H4L=2, 3, 3', 4'-diphenyl ether tetracarboxylic acid), phen (phen=1, 10-phenanthroline), 2, 2'-bipy (2, 2'-bipy=2, 2'-bipyridine), and cadmium chloride. Single-crystal X-ray diffraction analyses reveal that two polymers crystallize in the monoclinic or triclinic systems, space groups P21/c or P1. Polymers 1 and 2 show 1D chains composed of Cd4 or Cd2 units. The luminescent properties for two compounds were also investigated.
Two 1D cadmium(Ⅱ) coordination polymers, namely[Cd2(μ5-L)(phen)2]n (1) and {[Cd2(μ4-L)(2, 2'-bipy)2 (H2O)2]·2H2O}n (2), have been constructed hydrothermally using H4L (H4L=2, 3, 3', 4'-diphenyl ether tetracarboxylic acid), phen (phen=1, 10-phenanthroline), 2, 2'-bipy (2, 2'-bipy=2, 2'-bipyridine), and cadmium chloride. Single-crystal X-ray diffraction analyses reveal that two polymers crystallize in the monoclinic or triclinic systems, space groups P21/c or P1. Polymers 1 and 2 show 1D chains composed of Cd4 or Cd2 units. The luminescent properties for two compounds were also investigated.
2020, 36(9): 1735-1743
doi: 10.11862/CJIC.2020.183
Abstract:
A new Co(Ⅱ)-based coordination polymer (CP), namely {[Co(H3bcba)(bdmi)]·H2O}n (1), where H3bcba is 4, 4'-biscarboxyl-N, N-dibenzylamine and bdmi is 4, 4'-bis(2-methyl-1H-imidazol-1-yl)-1, 1'-biphenyl, has been hydrothermally synthesized and characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental analysis, thermogravimetric and Hirshfeld surface analyses. X-ray diffraction crystallographic analyses show that the partly deprotonated H3bcba ligand coordinates two Co (Ⅱ) ions with two carboxylate groups bending bidentate chelate modes, while bdmi serves as a μ2-bridging ligand in 1, result in a 2D polymeric grid frameworks with a 4-connected (4, 4) topology. In the crystal, a 3D supramolecular architecture is further formed by O-H…O and N-H…O hydrogen bonds, C-H…O and C-H…N interactions, as well as C-H…π stacking in 1. Complex 1 showed intense luminescence in the solid state, and exhibited a high selectivity and sensitivity for Fe3+ ions through the fluorescence quenching effect in aqueous solution at room temperature.
A new Co(Ⅱ)-based coordination polymer (CP), namely {[Co(H3bcba)(bdmi)]·H2O}n (1), where H3bcba is 4, 4'-biscarboxyl-N, N-dibenzylamine and bdmi is 4, 4'-bis(2-methyl-1H-imidazol-1-yl)-1, 1'-biphenyl, has been hydrothermally synthesized and characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental analysis, thermogravimetric and Hirshfeld surface analyses. X-ray diffraction crystallographic analyses show that the partly deprotonated H3bcba ligand coordinates two Co (Ⅱ) ions with two carboxylate groups bending bidentate chelate modes, while bdmi serves as a μ2-bridging ligand in 1, result in a 2D polymeric grid frameworks with a 4-connected (4, 4) topology. In the crystal, a 3D supramolecular architecture is further formed by O-H…O and N-H…O hydrogen bonds, C-H…O and C-H…N interactions, as well as C-H…π stacking in 1. Complex 1 showed intense luminescence in the solid state, and exhibited a high selectivity and sensitivity for Fe3+ ions through the fluorescence quenching effect in aqueous solution at room temperature.
2020, 36(9): 1744-1752
doi: 10.11862/CJIC.2020.194
Abstract:
A green fluorescent carbon dots (CDs) was synthesized from citric acid, formamide and concentrated nitric acid. The phase compositions, morphologies and fluorescence properties were characterized. The applications of the as-prepared CDs in ion detection and fluorescence imaging were studied as well. The results show that the as-synthesized CDs presented a good water-solubility and emitted bright green fluorescence with an excitation-independent photoluminescence (PL) behavior when the excitation wavelength ranged from 360 to 460 nm. The quantum yield was as high as 44.2%. Meanwhile, the green fluorescent CDs was pH sensitive and the normalized fluorescence intensity was linearly proportional to the pH values of solutions in a range of 4.5~8.5. Furthermore, the CDs also exhibited excellent selective response to Fe3+ with a good linear relationship between the fluorescence quenching efficiency (I0/I) and the Fe3+ concentration in a range of 0~1 000 μmol·L-1, and the detection limit was calculated to be 9.8 μmol·L-1.
A green fluorescent carbon dots (CDs) was synthesized from citric acid, formamide and concentrated nitric acid. The phase compositions, morphologies and fluorescence properties were characterized. The applications of the as-prepared CDs in ion detection and fluorescence imaging were studied as well. The results show that the as-synthesized CDs presented a good water-solubility and emitted bright green fluorescence with an excitation-independent photoluminescence (PL) behavior when the excitation wavelength ranged from 360 to 460 nm. The quantum yield was as high as 44.2%. Meanwhile, the green fluorescent CDs was pH sensitive and the normalized fluorescence intensity was linearly proportional to the pH values of solutions in a range of 4.5~8.5. Furthermore, the CDs also exhibited excellent selective response to Fe3+ with a good linear relationship between the fluorescence quenching efficiency (I0/I) and the Fe3+ concentration in a range of 0~1 000 μmol·L-1, and the detection limit was calculated to be 9.8 μmol·L-1.
2020, 36(9): 1753-1762
doi: 10.11862/CJIC.2020.191
Abstract:
In this work, we synthesized visible-light-driven Bi6Fe1.9Co0.1Ti3O18/Au (BFCTO/Au) nanocomposite photo-catalysts by a facile assembly method. The photocatalytic activity of BFCTO was enhanced by introducing Au nanoparticles with different sizes (~23 nm, ~36 nm, ~55 nm and~80 nm) into the BFCTO nanoplates. In particular, the BFCTO/Au-1 sample that was loaded with~23 nm Au nanoparticles exhibited the strongest photocatalytic activity under visible light irradiation.
In this work, we synthesized visible-light-driven Bi6Fe1.9Co0.1Ti3O18/Au (BFCTO/Au) nanocomposite photo-catalysts by a facile assembly method. The photocatalytic activity of BFCTO was enhanced by introducing Au nanoparticles with different sizes (~23 nm, ~36 nm, ~55 nm and~80 nm) into the BFCTO nanoplates. In particular, the BFCTO/Au-1 sample that was loaded with~23 nm Au nanoparticles exhibited the strongest photocatalytic activity under visible light irradiation.
2020, 36(9): 1763-1773
doi: 10.11862/CJIC.2020.204
Abstract:
A family of ruthenium(Ⅱ) polypyridyl complexes, namely[Ru(bpy)2(DMBbimHx)]y+ (bpy=2, 2'-bipyridine, DMBbimH2=7, 7'-dimethyl-2, 2'-bibenzimidazole, 1-A:x=2, y=2; 1-B:x=1, y=1; 1-C:x=0, y=0), were synthesized and determined by 1H NMR, UV-Vis absorption and electrochemical measurements. With the deprotonation of N-H in DMBbimHx ligands, the spectroscopic and electrochemical properties of complexes showed evident differences. Interestingly, the electrochemical properties of mono-deprotonated 1-B behaved very differently in dichloromethane and acetonitrile, which is due to different polarities of the solvents. In dichloromethane, mononuclear complex 1-B underwent a two-step oxidation. This is because[Ru(bpy)2(DMBbimH)]+ cations are bonded by hydrogen bonds to form dimers in weakly polar solvent, and proton-coupled electron transfer (PCET) exists between the[Ru(bpy)2 (DMBbimH)]+ cations. Single crystals of[Ru(bpy)2(DMBbimH)]PF6·2CH2Cl2 (2) were obtained from the solution of complex 1-B in dichloromethane. Crystal structure analysis shows that[Ru(bpy)2(DMBbimH)]+ cations are bonded by hydrogen bonds to form dimers, which is consistent with the result of the electrochemical measurements. However, hydrogen-bonded dimers couldn't exist stably in the more polar acetonitrile, therefore only one peak existing in the CV curve.
A family of ruthenium(Ⅱ) polypyridyl complexes, namely[Ru(bpy)2(DMBbimHx)]y+ (bpy=2, 2'-bipyridine, DMBbimH2=7, 7'-dimethyl-2, 2'-bibenzimidazole, 1-A:x=2, y=2; 1-B:x=1, y=1; 1-C:x=0, y=0), were synthesized and determined by 1H NMR, UV-Vis absorption and electrochemical measurements. With the deprotonation of N-H in DMBbimHx ligands, the spectroscopic and electrochemical properties of complexes showed evident differences. Interestingly, the electrochemical properties of mono-deprotonated 1-B behaved very differently in dichloromethane and acetonitrile, which is due to different polarities of the solvents. In dichloromethane, mononuclear complex 1-B underwent a two-step oxidation. This is because[Ru(bpy)2(DMBbimH)]+ cations are bonded by hydrogen bonds to form dimers in weakly polar solvent, and proton-coupled electron transfer (PCET) exists between the[Ru(bpy)2 (DMBbimH)]+ cations. Single crystals of[Ru(bpy)2(DMBbimH)]PF6·2CH2Cl2 (2) were obtained from the solution of complex 1-B in dichloromethane. Crystal structure analysis shows that[Ru(bpy)2(DMBbimH)]+ cations are bonded by hydrogen bonds to form dimers, which is consistent with the result of the electrochemical measurements. However, hydrogen-bonded dimers couldn't exist stably in the more polar acetonitrile, therefore only one peak existing in the CV curve.
2020, 36(9): 1774-1782
doi: 10.11862/CJIC.2020.205
Abstract:
Orotic acid as a pyrimidine derivative was less studied in the synthesis of metal-organic complexes. In this article, reactions of orotic acid as ligand with transition metal salts under solvothermal conditions gave rise to three new complexes, namely {[Cu(HOr)2]·2NH2(CH3)2}n (R-1), [Co2(HOr)2(bipy)(H2O)6]·2H2O (R-2) and {[Ni2(HOr)2 (1, 3-dpp)2(H2O)2] [Ni(HOr)(1, 3-dpp)(H2O)]2·(1, 3-dpp)·2H2O}n (R-3) (H3Or=orotic acid, bipy=4, 4'-bipyridine, 1, 3-dpp=1, 3-di(4-pyridyl)propane). All the complexes have been structurally characterized by single-crystal X-ray diffraction analyses and characterized by elemental analysis, infrared spectra (IR) and thermogravimetric analysis (TGA). X-ray crystallography analysis reveals that R-1 is mononuclear complex with 2D sheet structure, R-2 is a simple monomolecular complex, and R-3 is a complicated sandwich structure containing layers and chains. All the complexes are linked to form 3D framework through intermolecular hydrogen bonding interaction.
Orotic acid as a pyrimidine derivative was less studied in the synthesis of metal-organic complexes. In this article, reactions of orotic acid as ligand with transition metal salts under solvothermal conditions gave rise to three new complexes, namely {[Cu(HOr)2]·2NH2(CH3)2}n (R-1), [Co2(HOr)2(bipy)(H2O)6]·2H2O (R-2) and {[Ni2(HOr)2 (1, 3-dpp)2(H2O)2] [Ni(HOr)(1, 3-dpp)(H2O)]2·(1, 3-dpp)·2H2O}n (R-3) (H3Or=orotic acid, bipy=4, 4'-bipyridine, 1, 3-dpp=1, 3-di(4-pyridyl)propane). All the complexes have been structurally characterized by single-crystal X-ray diffraction analyses and characterized by elemental analysis, infrared spectra (IR) and thermogravimetric analysis (TGA). X-ray crystallography analysis reveals that R-1 is mononuclear complex with 2D sheet structure, R-2 is a simple monomolecular complex, and R-3 is a complicated sandwich structure containing layers and chains. All the complexes are linked to form 3D framework through intermolecular hydrogen bonding interaction.
2020, 36(9): 1783-1790
doi: 10.11862/CJIC.2020.208
Abstract:
A new mononuclear complex[Co(L)Cl2] (L=4-methyl-N, N-bis(pyridin-2-ylmethyl) aniline) was synthesized and characterized by infrared spectroscopy, elemental analysis and X-ray single crystal diffraction. The results show that the Co(Ⅱ) center of the complex is a distorted trigonal-bipyramidal configuration with N3Cl2 donor sets. The interaction between the complex and DNA was studied by the electron absorption, emission spectroscopy and gel electrophoresis. The results reveal that the complex bind to CT-DNA by partial intercalation binding mode, and in the presence of hydrogen peroxide as a inducer, the DNA cleavage abilities of the complex are significantly improved. The Oxidative mechanism has been demonstrated via the pathway involving both hydroxyl radicals (·OH) and singlet oxygen (1O2) as ROS, and the binding site between the complex and DNA may be in the large groove. In addition, in vitro cytotoxicity of the drug has been tested by MTT against HeLa, BGC-823 and NCI-H460 cell lines.
A new mononuclear complex[Co(L)Cl2] (L=4-methyl-N, N-bis(pyridin-2-ylmethyl) aniline) was synthesized and characterized by infrared spectroscopy, elemental analysis and X-ray single crystal diffraction. The results show that the Co(Ⅱ) center of the complex is a distorted trigonal-bipyramidal configuration with N3Cl2 donor sets. The interaction between the complex and DNA was studied by the electron absorption, emission spectroscopy and gel electrophoresis. The results reveal that the complex bind to CT-DNA by partial intercalation binding mode, and in the presence of hydrogen peroxide as a inducer, the DNA cleavage abilities of the complex are significantly improved. The Oxidative mechanism has been demonstrated via the pathway involving both hydroxyl radicals (·OH) and singlet oxygen (1O2) as ROS, and the binding site between the complex and DNA may be in the large groove. In addition, in vitro cytotoxicity of the drug has been tested by MTT against HeLa, BGC-823 and NCI-H460 cell lines.
2020, 36(9): 1791-1803
doi: 10.11862/CJIC.2020.209
Abstract:
A series of boron and/or fluorine containing ZSM-5 zeolites were synthesized and used for the methanol to propylene (MTP) reaction. The as-synthesized ZSM-5 were characterized by X-ray diffraction, N2 adsorption-desorption, 29Si solid nuclear magnetic resonance, Fourier transform infrared spectroscopy, scanning electron micro-scope, and ammonia temperature-programmed desorption methods. The ZSM-5 molecular sieve with higher crystal-linity can be synthesized under the conditions of boron and fluorine doping. The heteroatom doping improves the SiO2/Al2O3 ratio (nSiO2/nAl2O3) of the molecular sieve. Boron and fluorine doped ZSM-5 possessed reduced Lewis acid sites but increased Brønsted acid sites. Besides, the particle size of ZSM-5 decreased with both boron and fluorine doping. In the MTP reaction, the enhanced catalyst lifetime could be attributed to the low content of Lewis acid sites and less strong Brønsted acid sites on the ZSM-5 catalysts. NH4BF4 modified ZSM-5 catalyst (Z5-BF2) with reduced Lewis acid sites and appropriate Brønsted acid sites exhibited relatively high propylene selectivity and long catalyst lifetime.
A series of boron and/or fluorine containing ZSM-5 zeolites were synthesized and used for the methanol to propylene (MTP) reaction. The as-synthesized ZSM-5 were characterized by X-ray diffraction, N2 adsorption-desorption, 29Si solid nuclear magnetic resonance, Fourier transform infrared spectroscopy, scanning electron micro-scope, and ammonia temperature-programmed desorption methods. The ZSM-5 molecular sieve with higher crystal-linity can be synthesized under the conditions of boron and fluorine doping. The heteroatom doping improves the SiO2/Al2O3 ratio (nSiO2/nAl2O3) of the molecular sieve. Boron and fluorine doped ZSM-5 possessed reduced Lewis acid sites but increased Brønsted acid sites. Besides, the particle size of ZSM-5 decreased with both boron and fluorine doping. In the MTP reaction, the enhanced catalyst lifetime could be attributed to the low content of Lewis acid sites and less strong Brønsted acid sites on the ZSM-5 catalysts. NH4BF4 modified ZSM-5 catalyst (Z5-BF2) with reduced Lewis acid sites and appropriate Brønsted acid sites exhibited relatively high propylene selectivity and long catalyst lifetime.
2020, 36(9): 1620-1624
doi: 10.11862/CJIC.2020.184
Abstract:
K3ZrF7 was prepared by solvothermal method, and Mn4+ was doped by ion-exchange method to obtain high intensity red phosphors. The structures and morphologies of the materials were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The results show that pure K3ZrF7 can be obtained efficiently with oleylamine as solvent under anhydrous condition. When oleylamine is replaced with water, pure K2ZrF6 can be prepared successfully. The effect of doping concentration(molar fraction) of Mn4+ on PL intensity of the materials was also investigated. By comparing the luminescence behavior of two Mn4+ doped materials, it was found that the PL intensity of K3ZrF7:Mn4+ was more than 10 times higher than that of K2ZrF6:Mn4+ with the same doping concentration. The mechanism of luminescence intensity difference can be explained by crystal field theory. It is known that the crystal structure and coordination environment of doped ion are very important to PL intensity of materials. We consider that the higher PL intensity of K3ZrF7:Mn4+ may be relative to its larger asymmetry of local crystal field.
K3ZrF7 was prepared by solvothermal method, and Mn4+ was doped by ion-exchange method to obtain high intensity red phosphors. The structures and morphologies of the materials were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The results show that pure K3ZrF7 can be obtained efficiently with oleylamine as solvent under anhydrous condition. When oleylamine is replaced with water, pure K2ZrF6 can be prepared successfully. The effect of doping concentration(molar fraction) of Mn4+ on PL intensity of the materials was also investigated. By comparing the luminescence behavior of two Mn4+ doped materials, it was found that the PL intensity of K3ZrF7:Mn4+ was more than 10 times higher than that of K2ZrF6:Mn4+ with the same doping concentration. The mechanism of luminescence intensity difference can be explained by crystal field theory. It is known that the crystal structure and coordination environment of doped ion are very important to PL intensity of materials. We consider that the higher PL intensity of K3ZrF7:Mn4+ may be relative to its larger asymmetry of local crystal field.
2020, 36(9): 1625-1630
doi: 10.11862/CJIC.2020.182
Abstract:
Two 2D coordination polymers {[Eu4(HL)2(ox)2(H2O)10]·3H2O}n (1) and {[Tb2(HL) (ox) (H2O)5]·2H2O}n (2) (H5L=4-(4-carboxyphenyl)-pyridine-2, 3, 5, 6-tetracarboxylic acid; ox=oxalate) were synthesized by using europium or terbium perchlorate to react with a new organic penta-carboxylic acids under hydrothermal condition. Single crystal X-ray diffraction structure analyses show that the two complexes are isomorphic and crystallize in monoclinic crystal system, P21/c space group. The oxalate anions were formed perhaps by the decomposition of part of the ligands. A 2D layer is constructed by europium or terbium ions, oxalate anions and HL ligands. Both the complexes emitted the characteristic fluorescence of Eu (Ⅲ) or Tb (Ⅲ). The absolute quantum yields of the luminescence for 1 and 2 were 45% and 38%, respectively. The fluorescence lifetimes of 5D0 excited state for 1 and 5D4 excited state for 2 were also tested and the values were 1.83 and 1.07 ms, respectively.
Two 2D coordination polymers {[Eu4(HL)2(ox)2(H2O)10]·3H2O}n (1) and {[Tb2(HL) (ox) (H2O)5]·2H2O}n (2) (H5L=4-(4-carboxyphenyl)-pyridine-2, 3, 5, 6-tetracarboxylic acid; ox=oxalate) were synthesized by using europium or terbium perchlorate to react with a new organic penta-carboxylic acids under hydrothermal condition. Single crystal X-ray diffraction structure analyses show that the two complexes are isomorphic and crystallize in monoclinic crystal system, P21/c space group. The oxalate anions were formed perhaps by the decomposition of part of the ligands. A 2D layer is constructed by europium or terbium ions, oxalate anions and HL ligands. Both the complexes emitted the characteristic fluorescence of Eu (Ⅲ) or Tb (Ⅲ). The absolute quantum yields of the luminescence for 1 and 2 were 45% and 38%, respectively. The fluorescence lifetimes of 5D0 excited state for 1 and 5D4 excited state for 2 were also tested and the values were 1.83 and 1.07 ms, respectively.
2020, 36(9): 1631-1638
doi: 10.11862/CJIC.2020.203
Abstract:
A bis-pyridyhylhydrazone Schiff base ligand (L) was synthesized and characterized by 1H NMR, MS, FT-IR and elemental analysis. Two complexes, {[Cd(L)2Cl2]·2DMF·6H2O}n (1) and[Hg(L)Cl2]n (2), were synthesized from the reaction of the ligand with CdCl2 and HgCl2, respectively. The structures of the ligand and two complexes were determined via X-ray single crystal diffraction, which show that both of the two complexes have 1D-chain structures. Furthermore, the thermal stabilities and vapor adsorption for MeOH at room temperature were investigated. The results demonstrate that complex 2 has a better thermal stability than complex 1, while complex 1 has a better adsorption for MeOH because of its pore structures.
A bis-pyridyhylhydrazone Schiff base ligand (L) was synthesized and characterized by 1H NMR, MS, FT-IR and elemental analysis. Two complexes, {[Cd(L)2Cl2]·2DMF·6H2O}n (1) and[Hg(L)Cl2]n (2), were synthesized from the reaction of the ligand with CdCl2 and HgCl2, respectively. The structures of the ligand and two complexes were determined via X-ray single crystal diffraction, which show that both of the two complexes have 1D-chain structures. Furthermore, the thermal stabilities and vapor adsorption for MeOH at room temperature were investigated. The results demonstrate that complex 2 has a better thermal stability than complex 1, while complex 1 has a better adsorption for MeOH because of its pore structures.
2020, 36(9): 1639-1648
doi: 10.11862/CJIC.2020.187
Abstract:
An efficient self-sacrifice template method of Zn-MOF-74 was used to fabricate ZnO nanomaterials which exhibited selective and sensitive gas sensing response to NO2. Herein, the precursor of Zn-MOF-74 was synthesized via solvothermal strategy, and subsequently calcinated at different temperatures to gain ZnO nanomaterials. The structure, morphology, and sensing property of ZnO nanomaterials were investigated using thermogravimetric-differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD), infrared spectroscopy (FT-IR), X-ray photo-electron spectroscopy (XPS), nitrogen adsorption-desorption, scanning electron microscopy (SEM) and high power transmission electron microscopy (HRTEM). The results show that hexagonal columnar structure of ZnO450, which was obtained from calcination of Zn-MOF-74 at 450℃, was stacked by nanosheets composed of nanoparticles with average size of 20 nm, and some organic functional groups remaining on the surface as well as the absorbed oxygen content was obviously higher than that of samples calcinated at 350 and 550℃. The response of the sensor based on ZnO 450 to 100 mL·m-3 NO2 reached 77.40 which was 6~105 times higher than that of the selective gases. In addition, the low detection limit was 0.1 mL·m-3. Moreover, the response to NO2 was remain unchanged in the coexistence of the gases such as SO2, et al, indicating strong anti-interference ability. The sensor's excellent response to NO 2 is due to the high adsorbed oxygen content on the surface, and the large specific surface area and pore diameter, which are conducive to NO2 adsorption, surface reaction and diffusion.
An efficient self-sacrifice template method of Zn-MOF-74 was used to fabricate ZnO nanomaterials which exhibited selective and sensitive gas sensing response to NO2. Herein, the precursor of Zn-MOF-74 was synthesized via solvothermal strategy, and subsequently calcinated at different temperatures to gain ZnO nanomaterials. The structure, morphology, and sensing property of ZnO nanomaterials were investigated using thermogravimetric-differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD), infrared spectroscopy (FT-IR), X-ray photo-electron spectroscopy (XPS), nitrogen adsorption-desorption, scanning electron microscopy (SEM) and high power transmission electron microscopy (HRTEM). The results show that hexagonal columnar structure of ZnO450, which was obtained from calcination of Zn-MOF-74 at 450℃, was stacked by nanosheets composed of nanoparticles with average size of 20 nm, and some organic functional groups remaining on the surface as well as the absorbed oxygen content was obviously higher than that of samples calcinated at 350 and 550℃. The response of the sensor based on ZnO 450 to 100 mL·m-3 NO2 reached 77.40 which was 6~105 times higher than that of the selective gases. In addition, the low detection limit was 0.1 mL·m-3. Moreover, the response to NO2 was remain unchanged in the coexistence of the gases such as SO2, et al, indicating strong anti-interference ability. The sensor's excellent response to NO 2 is due to the high adsorbed oxygen content on the surface, and the large specific surface area and pore diameter, which are conducive to NO2 adsorption, surface reaction and diffusion.
2020, 36(9): 1649-1658
doi: 10.11862/CJIC.2020.186
Abstract:
The nano-porous Ni/RuO2 and Ni-Mo/RuO2 composite electrode material were prepared by de-alloying combined with deposition precipitation. The phase, element, morphology and structure, pore size and crystallinity of the electrode material were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), transmission electron microscope (TEM). The electrocatalytic hydrogen evolution of porous electrode was tested by linear sweep voltammetry, AC impedance and cyclic voltammetry. The analysis results showed that RuO2 was cladded on the surface of the Ni-based alloy skeleton due to polycondensation. The addition of Mo enhanced the amorphization of the Ni-Mo alloy and promoted the refinement of the pore size of the porous skeleton to form a bicontinuous and porous nanostructure. The addition of Mo and RuO2 and the increase of Mo content all improved the electrocatalytic hydrogen evolution performance. The nanoporous Ni2.5Mo2.5/RuO2 composite electrode had a better electrocatalytic hydrogen evolution activity:at a current density of 50 mA·cm-2, its hydrogen overpotential was 182 mV.
The nano-porous Ni/RuO2 and Ni-Mo/RuO2 composite electrode material were prepared by de-alloying combined with deposition precipitation. The phase, element, morphology and structure, pore size and crystallinity of the electrode material were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), transmission electron microscope (TEM). The electrocatalytic hydrogen evolution of porous electrode was tested by linear sweep voltammetry, AC impedance and cyclic voltammetry. The analysis results showed that RuO2 was cladded on the surface of the Ni-based alloy skeleton due to polycondensation. The addition of Mo enhanced the amorphization of the Ni-Mo alloy and promoted the refinement of the pore size of the porous skeleton to form a bicontinuous and porous nanostructure. The addition of Mo and RuO2 and the increase of Mo content all improved the electrocatalytic hydrogen evolution performance. The nanoporous Ni2.5Mo2.5/RuO2 composite electrode had a better electrocatalytic hydrogen evolution activity:at a current density of 50 mA·cm-2, its hydrogen overpotential was 182 mV.
2020, 36(9): 1659-1668
doi: 10.11862/CJIC.2020.185
Abstract:
Ca2-x-ySry-xSiO4:xCe3+, xLi+ solid solution phosphors were designed and prepared by a high temperature solid-state reaction in a reductive atmosphere. The results of the XRD reveal that as-synthesized samples are single-phase compounds, and a phase transition from monoclinic β-Ca2SiO4 to orthogonal α'-Ca2SiO4 exists (y=0~0.25). The excitation and emission spectra of the phosphors showed a gradual redshift with the increase of Sr content (y) from 0 to 0.25, which showed the largest Stokes shift (73 nm) for Ca1.75Sr0.25SiO4, and subsequently a blueshift showed up after a further increase of y value. Moreover, the host of Ca1.1Sr0.9SiO4 can induce Ce3+ ions preferentially to occupy the ten-coordinated Sr2+ sites (SrO10) while Li+ ions replace the eight-coordinated Ca2+ sites (CaO8). The optimized phosphor Ca1.05Sr0.85SiO4:0.05Ce3+, 0.05Li+ (CS0.85SO:Ce) possessed a high internal quantum efficiency (IQE) reached 91.18%. The temperature-dependent photoluminescence (PL) spectra showed that the PL intensity of CS0.85SO:Ce at 200℃ maintained 98.70% of that at room temperature. The luminescent mechanisms were discussed in detailed according to crystal structure, crystal field theory and the Dorenbos model.
Ca2-x-ySry-xSiO4:xCe3+, xLi+ solid solution phosphors were designed and prepared by a high temperature solid-state reaction in a reductive atmosphere. The results of the XRD reveal that as-synthesized samples are single-phase compounds, and a phase transition from monoclinic β-Ca2SiO4 to orthogonal α'-Ca2SiO4 exists (y=0~0.25). The excitation and emission spectra of the phosphors showed a gradual redshift with the increase of Sr content (y) from 0 to 0.25, which showed the largest Stokes shift (73 nm) for Ca1.75Sr0.25SiO4, and subsequently a blueshift showed up after a further increase of y value. Moreover, the host of Ca1.1Sr0.9SiO4 can induce Ce3+ ions preferentially to occupy the ten-coordinated Sr2+ sites (SrO10) while Li+ ions replace the eight-coordinated Ca2+ sites (CaO8). The optimized phosphor Ca1.05Sr0.85SiO4:0.05Ce3+, 0.05Li+ (CS0.85SO:Ce) possessed a high internal quantum efficiency (IQE) reached 91.18%. The temperature-dependent photoluminescence (PL) spectra showed that the PL intensity of CS0.85SO:Ce at 200℃ maintained 98.70% of that at room temperature. The luminescent mechanisms were discussed in detailed according to crystal structure, crystal field theory and the Dorenbos model.
2020, 36(9): 1669-1674
doi: 10.11862/CJIC.2020.189
Abstract:
A series of blue-emission materials based on phenol-pyridyl aza-fluoroboric complexes have been developed and investigated. The natural chiral building block (α-pinene) was successfully introduced into the present fluoroboric complexes, resulting in enhancement of fluorescence quantum efficiency of the complexes. Moreover, the effect of auxiliary substituents on the optical properties of these chiral complexes has also been investigated, involving absorption and emission spectra, photoluminescence decay, as well as fluorescence quantum efficiency. Based on the chirality of pinene group, we also investigated the circular dichroism spectra of the presented enantiomers.
A series of blue-emission materials based on phenol-pyridyl aza-fluoroboric complexes have been developed and investigated. The natural chiral building block (α-pinene) was successfully introduced into the present fluoroboric complexes, resulting in enhancement of fluorescence quantum efficiency of the complexes. Moreover, the effect of auxiliary substituents on the optical properties of these chiral complexes has also been investigated, involving absorption and emission spectra, photoluminescence decay, as well as fluorescence quantum efficiency. Based on the chirality of pinene group, we also investigated the circular dichroism spectra of the presented enantiomers.
2020, 36(9): 1675-1682
doi: 10.11862/CJIC.2020.193
Abstract:
Transition metal cobalt phosphide (CoP) nanocage was prepared by a combination of hydrothermal and calcination method. Scanning electron microscope (SEM), transmission electron microscope (TEM), scanning trans-mission electron microscope (STEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were used to characterize the morphology, structure, and elemental composition of CoP. The study found that the synthesized CoP had a hollow nanocage structure, which is conducive to providing more accessible catalytic active sites, promoting the transport of electrons or ions, and accelerating the catalytic reaction process. Cyclic voltammetry (CV) and chronoamperometry studies displayed that CoP nanocages had excellent electrocatalytic oxidation activity toward glucose. The non-enzymatic glucose electrochemical sensor based on the CoP nanocage modified glassy carbon electrode showed excellent performance. The sensor has wide linear ranges (0.04~3 mmol·L-1 and 3~8 mmol·L-1), low detection limit (3.8 μmol·L-1), high sensitivity, good selectivity, repeatability, reproducibility and stability. In addition, the sensor can be applied to quickly determination of glucose in real human serum sample.
Transition metal cobalt phosphide (CoP) nanocage was prepared by a combination of hydrothermal and calcination method. Scanning electron microscope (SEM), transmission electron microscope (TEM), scanning trans-mission electron microscope (STEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were used to characterize the morphology, structure, and elemental composition of CoP. The study found that the synthesized CoP had a hollow nanocage structure, which is conducive to providing more accessible catalytic active sites, promoting the transport of electrons or ions, and accelerating the catalytic reaction process. Cyclic voltammetry (CV) and chronoamperometry studies displayed that CoP nanocages had excellent electrocatalytic oxidation activity toward glucose. The non-enzymatic glucose electrochemical sensor based on the CoP nanocage modified glassy carbon electrode showed excellent performance. The sensor has wide linear ranges (0.04~3 mmol·L-1 and 3~8 mmol·L-1), low detection limit (3.8 μmol·L-1), high sensitivity, good selectivity, repeatability, reproducibility and stability. In addition, the sensor can be applied to quickly determination of glucose in real human serum sample.
2020, 36(9): 1683-1689
doi: 10.11862/CJIC.2020.195
Abstract:
Aiming at the problems of complex preparation process and difficult to control film thickness of powder MOF-derived materials, we used a facile method to prepare the CoSe2 and N co-doped carbon film (CoSe2/N-CF) derived from metal-organic framework thin film materials (PIZA-1) as counter electrode in DSSC, which takes advantage of simple preparation, strong adhesion and adjustable thickness. The morphology, structure and electrochemical performance of CoSe2/N-CF were systematic characterized and the relationship between film thickness and size of CoSe2 with photovoltaic performance of DSSC was discussed. The CoSe2/N-CF-15 exhibited outstanding catalytic activity and remarkable power conversion efficiency (PCE) of 8.68%, which is higher than that of Pt (7.97%).
Aiming at the problems of complex preparation process and difficult to control film thickness of powder MOF-derived materials, we used a facile method to prepare the CoSe2 and N co-doped carbon film (CoSe2/N-CF) derived from metal-organic framework thin film materials (PIZA-1) as counter electrode in DSSC, which takes advantage of simple preparation, strong adhesion and adjustable thickness. The morphology, structure and electrochemical performance of CoSe2/N-CF were systematic characterized and the relationship between film thickness and size of CoSe2 with photovoltaic performance of DSSC was discussed. The CoSe2/N-CF-15 exhibited outstanding catalytic activity and remarkable power conversion efficiency (PCE) of 8.68%, which is higher than that of Pt (7.97%).
2020, 36(9): 1690-1700
doi: 10.11862/CJIC.2020.201
Abstract:
NaEuTiO4 (NETO) with layered perovskite structure was synthesized by sol-gel method. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), cyclic voltammogram (CV) and charge-discharge test were used to characterize its structural, morphological and electrochemical properties of the NETO treated with dilute nitric acid. The results show that there was an ion exchange path of Na+→H+→Li+ for NETO beside the reported Na+→Li+ path. That is to say, Na+ could be exchanged with H+ in dilute acid to form HETO. Then HETO could transform to LETO by means of charge-discharge cycling. The LETO obtained by this route also had an excellent electrochemical performance. NETO-12 h showed the best electrochemical properties with the reversible capacity of about 213.2 mAh·g-1 after 300 cycles. Moreover, it exhibited a good rate capability.
NaEuTiO4 (NETO) with layered perovskite structure was synthesized by sol-gel method. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), cyclic voltammogram (CV) and charge-discharge test were used to characterize its structural, morphological and electrochemical properties of the NETO treated with dilute nitric acid. The results show that there was an ion exchange path of Na+→H+→Li+ for NETO beside the reported Na+→Li+ path. That is to say, Na+ could be exchanged with H+ in dilute acid to form HETO. Then HETO could transform to LETO by means of charge-discharge cycling. The LETO obtained by this route also had an excellent electrochemical performance. NETO-12 h showed the best electrochemical properties with the reversible capacity of about 213.2 mAh·g-1 after 300 cycles. Moreover, it exhibited a good rate capability.
High Capacity Organic Cathode Calix[4]quinone in Ionic Liquids Electrolyte for Lithium-Ion Batteries
2020, 36(9): 1701-1706
doi: 10.11862/CJIC.2020.199
Abstract:
In this work, calix[4 ]quinone (C4Q), with a high theoretical capacity up to 446 mAh·g-1, was selected as the cathode for lithium-ion batteries (LIBs). While the solubility issue in conventional organic electrolytes would prevent its electrochemistry properties from being fully exploited. To this end, the Li[TFSI]/[PY13] [TFSI] ([PY13] [TFSI]:N-methyl-N-propylpyrrolidiniumbis(trifluoromethanesulfonyl)amide) electrolyte was chosen to match C4Q cathode to assemble LIBs, which made positive progress in cycling stability and rate capability. At the current density of 0.1C, the discharge specific capacity was 280 mAh·g-1 (77% of initial capacity) after 100 cycles, and the capacity retention rate was as high as 72% after 1 000 cycles. At 1C, the capacity could be still maintained at about 154 mAh·g-1.
In this work, calix[
2020, 36(9): 1707-1716
doi: 10.11862/CJIC.2020.170
Abstract:
Firstly, layered CsTi2NbO7 was prepared by high temperature solid-state method, and then layered HTi2NbO7 was obtained by a proton-exchange reaction treated with HNO3 solution. Secondly, the obtained layered HTi2NbO7 was well dispersed in tetrabutylammonium hydroxide (TBAOH) solution in order to prepare HTi2NbO7 nanosheets by exfoliation reaction. Thirdly, the as-prepared HTi2NbO7 nanosheets were dried, and then mixed with urea. Finally, nitrogen-doped HTi2NbO7 nanosheet photocatalyst was successfully synthesized by heating the above mixture. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), Ultraviolet-Visible diffuse reflectance absorption spectrum (UV-Vis DRS) as well as N2 adsorption-desorption measurements to characterize the crystal structure, morphology, specific surface area, pore distribution and light absorption capacity of as-prepared samples in detail. It was found that the doped nitrogen resulted in an intrinsic narrowing band-gap so as to widen light response region, and the doped nitrogen atoms were mainly located at the interstitial position of Ti2NbO7- sheets and chemically bonded with hydrogen ions. Moreover, compared with N-doped HTi2NbO7, N-doped HTi2NbO7 nanosheets had a larger specific surface area and richer mesoporous structure due to the relatively loose and irregular arrangement of the titanium niobate nanosheets. Therefore, the N-doped HTi2NbO7 nanosheets exhibited higher visible-light photocatalytic activity for degradation of RhB than that for N-doped layered HTi2NbO7.
Firstly, layered CsTi2NbO7 was prepared by high temperature solid-state method, and then layered HTi2NbO7 was obtained by a proton-exchange reaction treated with HNO3 solution. Secondly, the obtained layered HTi2NbO7 was well dispersed in tetrabutylammonium hydroxide (TBAOH) solution in order to prepare HTi2NbO7 nanosheets by exfoliation reaction. Thirdly, the as-prepared HTi2NbO7 nanosheets were dried, and then mixed with urea. Finally, nitrogen-doped HTi2NbO7 nanosheet photocatalyst was successfully synthesized by heating the above mixture. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), Ultraviolet-Visible diffuse reflectance absorption spectrum (UV-Vis DRS) as well as N2 adsorption-desorption measurements to characterize the crystal structure, morphology, specific surface area, pore distribution and light absorption capacity of as-prepared samples in detail. It was found that the doped nitrogen resulted in an intrinsic narrowing band-gap so as to widen light response region, and the doped nitrogen atoms were mainly located at the interstitial position of Ti2NbO7- sheets and chemically bonded with hydrogen ions. Moreover, compared with N-doped HTi2NbO7, N-doped HTi2NbO7 nanosheets had a larger specific surface area and richer mesoporous structure due to the relatively loose and irregular arrangement of the titanium niobate nanosheets. Therefore, the N-doped HTi2NbO7 nanosheets exhibited higher visible-light photocatalytic activity for degradation of RhB than that for N-doped layered HTi2NbO7.
2020, 36(9): 1717-1727
doi: 10.11862/CJIC.2020.190
Abstract:
The effect of ferroelectric polarization on the activity enhancement of Bi2MoO6 photocatalyst was explored by applying ferroelectric field polarization to organic-inorganic composite film materials constructed by ferroelectric photocatalyst Bi2MoO6 and polymethyl methacrylate (PMMA). The efficiency of unpolarized Bi2MoO6 degradation of rhodamine B (RhB) was 57.6% under 40 min light irradiation, and the degradation efficiency of bisphenol A (BPA) was 33.4% under 150 min light irradiation. The photocatalytic activity of Bi2MoO6 material polarized for 1.5 h at 15 V voltages was greatly enhanced, and the degradation efficiency of RhB and BPA under the same conditions reached 98.1% and 79.2%, respectively. The reason for the enhancement of photocatalytic activity is attributed to the enhancement of the internal electric field. The ferroelectric domains of the internal electric field of unpolarized Bi2MoO6 were disordered and unevenly distributed, and photogenerated carriers were very prone to recombination. When the applied electric field polarized Bi2MoO6, the ferroelectric domains of Bi2MoO6 tended to be ordered, and the polarization direction tended to be the same. Positive charges were generated on one side of the surface (C+ region) and negative charges were generated on the other side (C-region). The polarized electric field from C-region to C+ region drives the photogenerated electrons and holes to migrate to C+ and C-regions, respectively. This process promotes the rapid migration of photogenerated charge carriers from the interior to the surface, improves and prolongs the separation efficiency and lifetime of photogenerated carriers, leading to the enhancement of photocatalytic activity.
The effect of ferroelectric polarization on the activity enhancement of Bi2MoO6 photocatalyst was explored by applying ferroelectric field polarization to organic-inorganic composite film materials constructed by ferroelectric photocatalyst Bi2MoO6 and polymethyl methacrylate (PMMA). The efficiency of unpolarized Bi2MoO6 degradation of rhodamine B (RhB) was 57.6% under 40 min light irradiation, and the degradation efficiency of bisphenol A (BPA) was 33.4% under 150 min light irradiation. The photocatalytic activity of Bi2MoO6 material polarized for 1.5 h at 15 V voltages was greatly enhanced, and the degradation efficiency of RhB and BPA under the same conditions reached 98.1% and 79.2%, respectively. The reason for the enhancement of photocatalytic activity is attributed to the enhancement of the internal electric field. The ferroelectric domains of the internal electric field of unpolarized Bi2MoO6 were disordered and unevenly distributed, and photogenerated carriers were very prone to recombination. When the applied electric field polarized Bi2MoO6, the ferroelectric domains of Bi2MoO6 tended to be ordered, and the polarization direction tended to be the same. Positive charges were generated on one side of the surface (C+ region) and negative charges were generated on the other side (C-region). The polarized electric field from C-region to C+ region drives the photogenerated electrons and holes to migrate to C+ and C-regions, respectively. This process promotes the rapid migration of photogenerated charge carriers from the interior to the surface, improves and prolongs the separation efficiency and lifetime of photogenerated carriers, leading to the enhancement of photocatalytic activity.
