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2019 Volume 35 Issue 6
2019, 35(6): 937-946
doi: 10.11862/CJIC.2019.112
Abstract:
A new type of material based on the rich lithium-layered solid solution material system, xLi2MnO3-(1-x)Li[Ni0.8Co0.15Al0.05]O2 (0.5 ≤ x ≤ 0.8) was obtained by spray dry process with post annealing treatment. The effect of x value on the structural and electrochemical properties of the materials was investigated by XRD, SEM, TEM, XPS, EIS and charge-discharge tested. Our results suggested that the crystal structure of the sample gradually changed from layered Li[Ni0.8Co0.15Al0.05]O2 type to Li2MnO3 type with the increase of x. Moreover, the quenching treatment in liquid nitrogen was helpful to improve the electrochemical properties of xLi2MnO3-(1-x)Li[Ni0.8Co0.15Al0.05]O2 (0.5 ≤ x ≤ 0.8), which was attributed to the change in terms of the micro structure and valence of the transit metals caused by quenching. The sample with x=0.6 after quenching treatment showed good electrochemical properties, with above 209 mAh·g-1 of reversible capacity after 100 cycles.
A new type of material based on the rich lithium-layered solid solution material system, xLi2MnO3-(1-x)Li[Ni0.8Co0.15Al0.05]O2 (0.5 ≤ x ≤ 0.8) was obtained by spray dry process with post annealing treatment. The effect of x value on the structural and electrochemical properties of the materials was investigated by XRD, SEM, TEM, XPS, EIS and charge-discharge tested. Our results suggested that the crystal structure of the sample gradually changed from layered Li[Ni0.8Co0.15Al0.05]O2 type to Li2MnO3 type with the increase of x. Moreover, the quenching treatment in liquid nitrogen was helpful to improve the electrochemical properties of xLi2MnO3-(1-x)Li[Ni0.8Co0.15Al0.05]O2 (0.5 ≤ x ≤ 0.8), which was attributed to the change in terms of the micro structure and valence of the transit metals caused by quenching. The sample with x=0.6 after quenching treatment showed good electrochemical properties, with above 209 mAh·g-1 of reversible capacity after 100 cycles.
2019, 35(6): 947-954
doi: 10.11862/CJIC.2019.134
Abstract:
The fluorine scandium nanocrystals (NCs) with different morphologies, phase structures and properties of upconversion luminescence (UCL) were synthesized through changing the reaction conditions such as the composition, the amount of the surfactant or the reaction time. The change of the ratio of surfactant oleic acid (OA)/oleylamine (OM) made the crystal structure change from cubic ScF3:Yb, Er to orthorhombic KSc2F7:Yb, Er NCs with the enhanced UCL, while the morphology transformed from small to bulky. The UCL of the KSc2F7 NCs could be tuned from blue through white, and then to dominant purple emissions by changing doped element under the excitation of 980 nm laser.
The fluorine scandium nanocrystals (NCs) with different morphologies, phase structures and properties of upconversion luminescence (UCL) were synthesized through changing the reaction conditions such as the composition, the amount of the surfactant or the reaction time. The change of the ratio of surfactant oleic acid (OA)/oleylamine (OM) made the crystal structure change from cubic ScF3:Yb, Er to orthorhombic KSc2F7:Yb, Er NCs with the enhanced UCL, while the morphology transformed from small to bulky. The UCL of the KSc2F7 NCs could be tuned from blue through white, and then to dominant purple emissions by changing doped element under the excitation of 980 nm laser.
2019, 35(6): 955-964
doi: 10.11862/CJIC.2019.127
Abstract:
Ag3PO4/Ag2S/g-C3N4 composite photocatalysts were successfully prepared by a deposition-ion exchanged combined method. And the obtained samples were characterized by X-ray powder diffractometer (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), N2 adsorption and desorption isotherms, UV-visible diffuse reflectance spectroscopy, fluorescence spectrophotometry and so on. The catalytic activity and stability of the catalysts were evaluated by degradation of rhodamine B under visible light. The effect of molar ratio of sodium sulfide to silver phosphate (nNa2S/nAg3PO4) on the photocatalytic performance of the silver phosphate was studied. In addition, the photocatalytic mechanism was also investigated. The results show that, with the increase of nNa2S/nAg3PO4, the activity of the obtained composite catalytic material increased firstly and then decreased. When nNa2S/nAg3PO4 was 1.5%, the obtained ASC1.5 catalyst could completely degrade rhodamine B within 40 min under visible light irradiation, and also maintained high activity after five-cycle use. Compared with single silver phosphate, the activity and stability of Ag3PO4/Ag2S/g-C3N4 composite photocatalytic materials were significantly improved, which was mainly attributed to the increase of surface area and the presence of porous structure that enhanced separating efficiency of electron-hole pairs. The study of photocatalytic mechanism over the composite catalyst have shown that h+, ·O2- and ·OH were the main active species in the photocatalytic process. The order of the role of the above three species was:h+ > ·O2- > ·OH.
Ag3PO4/Ag2S/g-C3N4 composite photocatalysts were successfully prepared by a deposition-ion exchanged combined method. And the obtained samples were characterized by X-ray powder diffractometer (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), N2 adsorption and desorption isotherms, UV-visible diffuse reflectance spectroscopy, fluorescence spectrophotometry and so on. The catalytic activity and stability of the catalysts were evaluated by degradation of rhodamine B under visible light. The effect of molar ratio of sodium sulfide to silver phosphate (nNa2S/nAg3PO4) on the photocatalytic performance of the silver phosphate was studied. In addition, the photocatalytic mechanism was also investigated. The results show that, with the increase of nNa2S/nAg3PO4, the activity of the obtained composite catalytic material increased firstly and then decreased. When nNa2S/nAg3PO4 was 1.5%, the obtained ASC1.5 catalyst could completely degrade rhodamine B within 40 min under visible light irradiation, and also maintained high activity after five-cycle use. Compared with single silver phosphate, the activity and stability of Ag3PO4/Ag2S/g-C3N4 composite photocatalytic materials were significantly improved, which was mainly attributed to the increase of surface area and the presence of porous structure that enhanced separating efficiency of electron-hole pairs. The study of photocatalytic mechanism over the composite catalyst have shown that h+, ·O2- and ·OH were the main active species in the photocatalytic process. The order of the role of the above three species was:h+ > ·O2- > ·OH.
2019, 35(6): 965-970
doi: 10.11862/CJIC.2019.106
Abstract:
One novel free porphyrin modified with 5-fluorouracil (5-(2-(5-fluorouracil-3-yl)-ethoxyphenyl)-10, 15, 20-triphenyl porphyrin, L) and its manganese complex (MnL), zinc complex (ZnL) were synthesized. They were characterized by UV-Vis, IR, 1H NMR and MS. Their fluorescence properties and electrochemical properties were examined. The antitumor activities of them were evaluated by SRB assay in vitro against three human cancer cell lines. The results indicate that metal ions have a significant influence on the fluorescence intensity of complexes under the same experimental conditions:the fluorescence quenching was exhibited for zinc complex, but fluorescence signal had not been detected for manganese complex. The cyclic voltammetry of manganese complex was different from those of free porphyrin and zinc complex, which showed not only the redox of porphyrin ring but also the redox of Mn2+ ion. The biological tests revealed that manganese complex has a higher inhibitory rate than L and ZnL, but is less active than 5-fluorouracil.
One novel free porphyrin modified with 5-fluorouracil (5-(2-(5-fluorouracil-3-yl)-ethoxyphenyl)-10, 15, 20-triphenyl porphyrin, L) and its manganese complex (MnL), zinc complex (ZnL) were synthesized. They were characterized by UV-Vis, IR, 1H NMR and MS. Their fluorescence properties and electrochemical properties were examined. The antitumor activities of them were evaluated by SRB assay in vitro against three human cancer cell lines. The results indicate that metal ions have a significant influence on the fluorescence intensity of complexes under the same experimental conditions:the fluorescence quenching was exhibited for zinc complex, but fluorescence signal had not been detected for manganese complex. The cyclic voltammetry of manganese complex was different from those of free porphyrin and zinc complex, which showed not only the redox of porphyrin ring but also the redox of Mn2+ ion. The biological tests revealed that manganese complex has a higher inhibitory rate than L and ZnL, but is less active than 5-fluorouracil.
2019, 35(6): 971-977
doi: 10.11862/CJIC.2019.132
Abstract:
For the sake of tumor diagnosis and treatment integration, the magnetic gold nanocomposite (Au-Fe3O4) with magnetic thermo, photo thermo, and catalysis properties, was prepared by epitaxial oxidation and growth of iron oxide with gold nanoparticles as seeds and coated with the mesoporous silica layer (Au-Fe3O4@mSiO2) using cetyltrimethyl ammonium bromide (CTAB) and F127 as two template agents by sol-gel method. The prepared Au-Fe3O4 nanoparticles were dumbbell type with good single dispersion, uniform size distribution and particle size of 12~15 nm. When the magnetic field current increased from 25.5 to 42.5 A, heating rate of the sample (25 mg·mL-1) increased from 0.39 to 0.76℃·min-1. When the laser density increased from 0.3 to 1.2 W·cm-2, the temperature of the solution (25 mg·mL-1) increased from 0.69 to 2℃·min-1. Both the magneto thermal and photo thermal properties of Au-Fe3O4@mSiO2 composites were directly proportional to the concentration and the strength of the external magnetic field/density of laser irradiation. The photo thermal property of the composite was better than that of magneto thermal property. The catalytic release of NO by the Au-Fe3O4@mSiO2 complex (25 mg·mL-1 in S-nitrosoglutathione (GSNO)) reached a sustained and stable release within 60 min, with a maximum amount of 9.743 μmol·L-1.
For the sake of tumor diagnosis and treatment integration, the magnetic gold nanocomposite (Au-Fe3O4) with magnetic thermo, photo thermo, and catalysis properties, was prepared by epitaxial oxidation and growth of iron oxide with gold nanoparticles as seeds and coated with the mesoporous silica layer (Au-Fe3O4@mSiO2) using cetyltrimethyl ammonium bromide (CTAB) and F127 as two template agents by sol-gel method. The prepared Au-Fe3O4 nanoparticles were dumbbell type with good single dispersion, uniform size distribution and particle size of 12~15 nm. When the magnetic field current increased from 25.5 to 42.5 A, heating rate of the sample (25 mg·mL-1) increased from 0.39 to 0.76℃·min-1. When the laser density increased from 0.3 to 1.2 W·cm-2, the temperature of the solution (25 mg·mL-1) increased from 0.69 to 2℃·min-1. Both the magneto thermal and photo thermal properties of Au-Fe3O4@mSiO2 composites were directly proportional to the concentration and the strength of the external magnetic field/density of laser irradiation. The photo thermal property of the composite was better than that of magneto thermal property. The catalytic release of NO by the Au-Fe3O4@mSiO2 complex (25 mg·mL-1 in S-nitrosoglutathione (GSNO)) reached a sustained and stable release within 60 min, with a maximum amount of 9.743 μmol·L-1.
2019, 35(6): 978-986
doi: 10.11862/CJIC.2019.107
Abstract:
A series of Cr/Al2O3-TiO2 catalysts were successfully synthesized by the combination of sol-gel method and impregnation method for catalytic oxidation of NO. The effects of Cr load, different metal loading and calcination temperature on the physical-chemical properties of Cr/Al2O3-TiO2 catalysts were exhaustively investigated by using different characterization techniques, such as the temperature programmed oxidation (TPO), X-ray diffraction (XRD), H2-temperature programmed reduction (H2-TPR), N2 adsorption-desorption method and X-ray photoelectron spectroscopy (XPS). The TPO results showed that the 10%(w/w) Cr/Al2O3-TiO2 possessed the highest performance. Compared the doping of different metals, Co-Cr/Al2O3-TiO2 obtained excellent catalytic activity and high specific surface area at 550℃ calcination temperature. H2-TPR show that both the Co loading and calcination temperature can significantly improve the low-temperature redox ability of the catalyst, and be beneficial to form more active species of Cr6+, indicating that Co-Cr has good synergistic catalysis. XPS revealed that the Co doping greatly increased the content of Cr6+, surface adsorbed oxygen (Oβ), and oxygen vacancies. Besides, when the calcination temperature increased (450~550℃), the lattice oxygen continuously moved to the surface of catalyst and increased the ratio of Oβ, leading to the further enhancement of catalytic activity of Co-Cr/Al2O3-TiO2. Based the characterization results and catalytic performance of Cr/Al2O3-TiO2, it is proved that both Cr6+ and Oβ are important active species for the catalytic oxidation of NO.
A series of Cr/Al2O3-TiO2 catalysts were successfully synthesized by the combination of sol-gel method and impregnation method for catalytic oxidation of NO. The effects of Cr load, different metal loading and calcination temperature on the physical-chemical properties of Cr/Al2O3-TiO2 catalysts were exhaustively investigated by using different characterization techniques, such as the temperature programmed oxidation (TPO), X-ray diffraction (XRD), H2-temperature programmed reduction (H2-TPR), N2 adsorption-desorption method and X-ray photoelectron spectroscopy (XPS). The TPO results showed that the 10%(w/w) Cr/Al2O3-TiO2 possessed the highest performance. Compared the doping of different metals, Co-Cr/Al2O3-TiO2 obtained excellent catalytic activity and high specific surface area at 550℃ calcination temperature. H2-TPR show that both the Co loading and calcination temperature can significantly improve the low-temperature redox ability of the catalyst, and be beneficial to form more active species of Cr6+, indicating that Co-Cr has good synergistic catalysis. XPS revealed that the Co doping greatly increased the content of Cr6+, surface adsorbed oxygen (Oβ), and oxygen vacancies. Besides, when the calcination temperature increased (450~550℃), the lattice oxygen continuously moved to the surface of catalyst and increased the ratio of Oβ, leading to the further enhancement of catalytic activity of Co-Cr/Al2O3-TiO2. Based the characterization results and catalytic performance of Cr/Al2O3-TiO2, it is proved that both Cr6+ and Oβ are important active species for the catalytic oxidation of NO.
2019, 35(6): 987-995
doi: 10.11862/CJIC.2019.119
Abstract:
Core-shell structure multifunctional Ag@BaGdF5:Yb3+, Ho3+ nanocomposites were prepared by a simple wet method. XRD patterns showed that the nanocomposites consisted of cubic phase Ag and BaGdF5. Electron microscope images indicated that the nanocomposites were spherical shape with the thickness of~14 nm (BaGdF5:Yb3+, Ho3+ as shell) and a diameter of 77 nm (Ag nanoparticles as core). The nanocomposites had good upconversion emission with the strongest green emission centered at about 540 nm from the photoluminescence spectra, which is helpful to apply in intracellular imaging to diagnose lesion. Furthermore, the samples possessed better paramagnetism and photothermal conversion properties. MTT measurement demonstrates that the nanocomposites have better biocompatibility. When incubated with HeLa cells, the nanocomposites had bright green upconversion imaging under 980 nm irradiation. Compared with commercial computed tomography (CT) imaging contrast agent iobitridol, the Ag@BaGdF5:Yb3+, Ho3+ nanocomposites had higher CT imaging properties. The heat converted from the nanocomposites could kill HeLa cells.
Core-shell structure multifunctional Ag@BaGdF5:Yb3+, Ho3+ nanocomposites were prepared by a simple wet method. XRD patterns showed that the nanocomposites consisted of cubic phase Ag and BaGdF5. Electron microscope images indicated that the nanocomposites were spherical shape with the thickness of~14 nm (BaGdF5:Yb3+, Ho3+ as shell) and a diameter of 77 nm (Ag nanoparticles as core). The nanocomposites had good upconversion emission with the strongest green emission centered at about 540 nm from the photoluminescence spectra, which is helpful to apply in intracellular imaging to diagnose lesion. Furthermore, the samples possessed better paramagnetism and photothermal conversion properties. MTT measurement demonstrates that the nanocomposites have better biocompatibility. When incubated with HeLa cells, the nanocomposites had bright green upconversion imaging under 980 nm irradiation. Compared with commercial computed tomography (CT) imaging contrast agent iobitridol, the Ag@BaGdF5:Yb3+, Ho3+ nanocomposites had higher CT imaging properties. The heat converted from the nanocomposites could kill HeLa cells.
2019, 35(6): 996-1004
doi: 10.11862/CJIC.2019.135
Abstract:
A composite photocatalyst Bi2WO6/UiO-66 was prepared by hydrothermal method. The effect of template glacial acetic acid (CH3COOH) on the morphology of UiO-66 and the effects of different molar ratios of Bi and Zr on the photocatalytic performance of the composite were investigated. XRD, SEM, N2 adsorption-desorption, UV-Vis DRS and XPS were used to characterize the phase, morphology, specific surface area, optical absorption performance and element composition of the catalyst. The experimental results show that when nBi:nZr=2:1, the photocatalytic activity of RhB by Bi2WO6/UiO-66 is the highest. The relative concentration of RhB decreased 98.5% after 50 minutes of visible light irradiation. After five recycling experiments, there was no significant decrease in photocatalytic activity, but the photocatalytic activity of pure Bi2WO6 decreased greatly, which indicated that the stability of the complex is higher than that of pure Bi2WO6. According to free radical trapping experiments, it is proved that holes (h+) play an important role in photocatalysis. The reasons for the improvement of photocatalytic activity were further explained by electrochemical test. The band gap and valence band position of the material were obtained by UV-Vis DRS and VB-XPS, and the possible photocatalysis mechanism was put forward.
A composite photocatalyst Bi2WO6/UiO-66 was prepared by hydrothermal method. The effect of template glacial acetic acid (CH3COOH) on the morphology of UiO-66 and the effects of different molar ratios of Bi and Zr on the photocatalytic performance of the composite were investigated. XRD, SEM, N2 adsorption-desorption, UV-Vis DRS and XPS were used to characterize the phase, morphology, specific surface area, optical absorption performance and element composition of the catalyst. The experimental results show that when nBi:nZr=2:1, the photocatalytic activity of RhB by Bi2WO6/UiO-66 is the highest. The relative concentration of RhB decreased 98.5% after 50 minutes of visible light irradiation. After five recycling experiments, there was no significant decrease in photocatalytic activity, but the photocatalytic activity of pure Bi2WO6 decreased greatly, which indicated that the stability of the complex is higher than that of pure Bi2WO6. According to free radical trapping experiments, it is proved that holes (h+) play an important role in photocatalysis. The reasons for the improvement of photocatalytic activity were further explained by electrochemical test. The band gap and valence band position of the material were obtained by UV-Vis DRS and VB-XPS, and the possible photocatalysis mechanism was put forward.
2019, 35(6): 1005-1012
doi: 10.11862/CJIC.2019.114
Abstract:
Oxygen-doped carbon nitride nanosheets catalyst (CNO) was synthesized by two-step thermal polymerization method using oxalic acid as oxygen source, melamine and urea as raw materials. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet-visible absorption spectroscopy (UV-Vis), X-ray photoelectron spectroscopy (XPS), fluorescence spectroscopy (PL), and electrochemical measurements were carried out to characterize and analyze the structures of catalysts. The photocatalytic reduction properties of CNO were tested by H2 production from water splitting under visible light irradiation. The results showed that O elements directly replaced N in the triazine ring structure and bonded to the sp2 hybridized carbon to form CNO. The CNO showed good layered structure, improved absorption of visible light, and lowered band gap. Due to the O doping, the separation and transmission of photogenerated electron-hole pairs were accelerated. Under visible light irradiation, the hydrogen generation rate from water by CNO was greatly enhanced and the evolution rate was up to 88.6 μmol·h-1, which was 3.91 times as undoped CN.
Oxygen-doped carbon nitride nanosheets catalyst (CNO) was synthesized by two-step thermal polymerization method using oxalic acid as oxygen source, melamine and urea as raw materials. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet-visible absorption spectroscopy (UV-Vis), X-ray photoelectron spectroscopy (XPS), fluorescence spectroscopy (PL), and electrochemical measurements were carried out to characterize and analyze the structures of catalysts. The photocatalytic reduction properties of CNO were tested by H2 production from water splitting under visible light irradiation. The results showed that O elements directly replaced N in the triazine ring structure and bonded to the sp2 hybridized carbon to form CNO. The CNO showed good layered structure, improved absorption of visible light, and lowered band gap. Due to the O doping, the separation and transmission of photogenerated electron-hole pairs were accelerated. Under visible light irradiation, the hydrogen generation rate from water by CNO was greatly enhanced and the evolution rate was up to 88.6 μmol·h-1, which was 3.91 times as undoped CN.
2019, 35(6): 1013-1019
doi: 10.11862/CJIC.2019.138
Abstract:
A simple method for preparing flower-like CuxS nanomaterials by sulfidation of pre-prepared mesoporous Cu2O microspheres was reported. CuxS/FTO counter electrodes were further obtained via screen printing technique. X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to characterize the structure and morphology of the prepared materials, and the influences of the layers of CuxS, solution concentration and sulfidation time on the electrochemically catalytic activity of counter electrodes as well as the conversion efficiency of the assembled quantum dot sensitized solar cells were also investigated. Results showed that the flower-like CuxS had excellent catalytic activity and Zn-Cu-In-Se based quantum dot sensitized solar cells had good performance with conversion efficiency as high as 8.80%.
A simple method for preparing flower-like CuxS nanomaterials by sulfidation of pre-prepared mesoporous Cu2O microspheres was reported. CuxS/FTO counter electrodes were further obtained via screen printing technique. X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to characterize the structure and morphology of the prepared materials, and the influences of the layers of CuxS, solution concentration and sulfidation time on the electrochemically catalytic activity of counter electrodes as well as the conversion efficiency of the assembled quantum dot sensitized solar cells were also investigated. Results showed that the flower-like CuxS had excellent catalytic activity and Zn-Cu-In-Se based quantum dot sensitized solar cells had good performance with conversion efficiency as high as 8.80%.
2019, 35(6): 1020-1026
doi: 10.11862/CJIC.2019.129
Abstract:
N-heterocyclic carbene copper(Ⅰ) complexes have received great attention in organic light emitting diodes (OLEDs). However, a perusal of the literature shows that the three-coordinated species are widely studied, while studies on the luminescent properties of the four-coordinated NHC-Cu(Ⅰ) complexes is very scarce. With the aim of expanding this work, and motivated by the rich photophysical properties of the four-coordinated NHC-Cu(Ⅰ) complexes, we now present the preparation of the two four-coordinated NHC-Cu(Ⅰ) complexes. The N-heterocyclic carbene ligands, (Ph-Im-flumePy)PF6 and (Ph-BenIm-mePy)PF6, were synthesized by using imidazole, benzimidazole, benzyl bromide and 2-bromo-5-fluoro-6-methylpyridine as starting materials. Then the ligands were reacted with Cu powder and bis(2-diphenylphosphino)phenyl ether (POP) to synthesize the four-coordinated N-heterocyclic carbene copper(Ⅰ) complexes[Cu(Ph-Im-flumePy)(POP)]PF6 (P1) and[Cu(Ph-BenIm-flumePy)(POP)]PF6 (P2). The resulting complexes were characterized by 1H NMR and HRMS. The optical properties of the complexes were systematically investigated by measuring the UV-visible absorption spectra, luminescence spectra and phosphorescence lifetime of the complexes. The results show that the complex P1 and P2 displayed the lowest-absorption peak around at 325 and 335 nm, respectively. In the powder state, complex P1 exhibited strong green emission at 514 nm with 82.6% photoluminescence quantum yield (QY), as well as a 56 μs excited state lifetime at room temperature, while complex P2 showed the emission peak centered at 516 nm with the QY value of 49.2%, as well as the excited state lifetime of 50.6 μs. In the PMMA films (10%, w/w), complex P1 showed the emission wavelength at 505 nm and had the QY of 38.0% and the excited state lifetime of 40.7 μs, whereas complex P2 exhibited the strong green emission at 508 nm with the QY of 44.2% and the excited state lifetime of 61 μs.
N-heterocyclic carbene copper(Ⅰ) complexes have received great attention in organic light emitting diodes (OLEDs). However, a perusal of the literature shows that the three-coordinated species are widely studied, while studies on the luminescent properties of the four-coordinated NHC-Cu(Ⅰ) complexes is very scarce. With the aim of expanding this work, and motivated by the rich photophysical properties of the four-coordinated NHC-Cu(Ⅰ) complexes, we now present the preparation of the two four-coordinated NHC-Cu(Ⅰ) complexes. The N-heterocyclic carbene ligands, (Ph-Im-flumePy)PF6 and (Ph-BenIm-mePy)PF6, were synthesized by using imidazole, benzimidazole, benzyl bromide and 2-bromo-5-fluoro-6-methylpyridine as starting materials. Then the ligands were reacted with Cu powder and bis(2-diphenylphosphino)phenyl ether (POP) to synthesize the four-coordinated N-heterocyclic carbene copper(Ⅰ) complexes[Cu(Ph-Im-flumePy)(POP)]PF6 (P1) and[Cu(Ph-BenIm-flumePy)(POP)]PF6 (P2). The resulting complexes were characterized by 1H NMR and HRMS. The optical properties of the complexes were systematically investigated by measuring the UV-visible absorption spectra, luminescence spectra and phosphorescence lifetime of the complexes. The results show that the complex P1 and P2 displayed the lowest-absorption peak around at 325 and 335 nm, respectively. In the powder state, complex P1 exhibited strong green emission at 514 nm with 82.6% photoluminescence quantum yield (QY), as well as a 56 μs excited state lifetime at room temperature, while complex P2 showed the emission peak centered at 516 nm with the QY value of 49.2%, as well as the excited state lifetime of 50.6 μs. In the PMMA films (10%, w/w), complex P1 showed the emission wavelength at 505 nm and had the QY of 38.0% and the excited state lifetime of 40.7 μs, whereas complex P2 exhibited the strong green emission at 508 nm with the QY of 44.2% and the excited state lifetime of 61 μs.
2019, 35(6): 1027-1033
doi: 10.11862/CJIC.2019.113
Abstract:
Sr3Fe2-xNixO7-δ (x=0, 0.1, 0.2, 0.3) were synthesized by a modified complexing sol-gel process as cathode for intermediate temperature solid oxide fuel cells (IT-SOFCs). The phase structure, thermodynamic properties and electrochemical properties of the materials were characterized by X-ray diffraction, thermal expansion coefficient test, conductivity test, polarization impedance (Rp) test and single cell performance test. The results showed that all samples were successfully synthesized with perovskite-like structure. The Sr3Fe2-xNixO7-δ cathode exhibited good chemical compatibility with the Ce0.8Sm0.2O1.9 (SDC) electrolyte at 1 000℃ for 5 h. The coefficient of thermal expansion (TEC) decreased with the increase of x, and the minimum value was 1.839×10-5 K-1. Its high temperature conductivity increased with the increase of Ni doping content, and SFN30 had the highest conductivity of 101 S·cm-1. The Rp of this series of samples showed a trend of decrease first and then increase with the increase of the doping content of Ni. SFN10 had the lowest polarization impedance of 0.078 8 Ω·cm2 at 800℃. The trend of the output power of the electrolyte-supported cell was consistent with the trend of polarization impedance. The SFN10 achieved an output power density of 421.6 mW·cm-2 at 800℃.
Sr3Fe2-xNixO7-δ (x=0, 0.1, 0.2, 0.3) were synthesized by a modified complexing sol-gel process as cathode for intermediate temperature solid oxide fuel cells (IT-SOFCs). The phase structure, thermodynamic properties and electrochemical properties of the materials were characterized by X-ray diffraction, thermal expansion coefficient test, conductivity test, polarization impedance (Rp) test and single cell performance test. The results showed that all samples were successfully synthesized with perovskite-like structure. The Sr3Fe2-xNixO7-δ cathode exhibited good chemical compatibility with the Ce0.8Sm0.2O1.9 (SDC) electrolyte at 1 000℃ for 5 h. The coefficient of thermal expansion (TEC) decreased with the increase of x, and the minimum value was 1.839×10-5 K-1. Its high temperature conductivity increased with the increase of Ni doping content, and SFN30 had the highest conductivity of 101 S·cm-1. The Rp of this series of samples showed a trend of decrease first and then increase with the increase of the doping content of Ni. SFN10 had the lowest polarization impedance of 0.078 8 Ω·cm2 at 800℃. The trend of the output power of the electrolyte-supported cell was consistent with the trend of polarization impedance. The SFN10 achieved an output power density of 421.6 mW·cm-2 at 800℃.
2019, 35(6): 1034-1040
doi: 10.11862/CJIC.2019.115
Abstract:
A series of Pt-Ag2CO3 composite photocatalysts were synthesized via NaBH4 reduction method. Pt deposition effects on photocatalytic performance of Ag2CO3 were evaluated by photocatalytic degradation of methyl orange under visible light irradiation. The influence of Pt deposition on the physicochemical properties of Ag2CO3 crystal were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), Fourier translation infrared spectroscopy (FT-IR), photoluminescence (PL) emission spectroscopy, and UV-Vis diffuse reflectance spectra (UV-Vis DRS), photocurrent (PC), and N2 physical adsorption. The results show that deposition of 0.1%~0.5% (w/w) concentration of Pt brought about 3 times photocatalytic activity of the Ag2CO3 and the stability was largely promoted. The presence of Pt brings about the strong visible light absorption and the increase of surface area and amount of -OH groups. Besides, the presence of Pt deposited on Ag2CO3 can retard fast charge-pair recombination by serving as an electron sink to facilitate the separation of photogenerated electrons (e-) and holes (h+). Therefore, more e- and h+ are available for production more radicals to decompose the organic dyes. The fast transfer rate of electrons can also reduce the photoreduction (Ag++e → Ag) and increase the ability of Ag2CO3 to resist the photocorrosion.
A series of Pt-Ag2CO3 composite photocatalysts were synthesized via NaBH4 reduction method. Pt deposition effects on photocatalytic performance of Ag2CO3 were evaluated by photocatalytic degradation of methyl orange under visible light irradiation. The influence of Pt deposition on the physicochemical properties of Ag2CO3 crystal were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), Fourier translation infrared spectroscopy (FT-IR), photoluminescence (PL) emission spectroscopy, and UV-Vis diffuse reflectance spectra (UV-Vis DRS), photocurrent (PC), and N2 physical adsorption. The results show that deposition of 0.1%~0.5% (w/w) concentration of Pt brought about 3 times photocatalytic activity of the Ag2CO3 and the stability was largely promoted. The presence of Pt brings about the strong visible light absorption and the increase of surface area and amount of -OH groups. Besides, the presence of Pt deposited on Ag2CO3 can retard fast charge-pair recombination by serving as an electron sink to facilitate the separation of photogenerated electrons (e-) and holes (h+). Therefore, more e- and h+ are available for production more radicals to decompose the organic dyes. The fast transfer rate of electrons can also reduce the photoreduction (Ag++e → Ag) and increase the ability of Ag2CO3 to resist the photocorrosion.
2019, 35(6): 1041-1049
doi: 10.11862/CJIC.2019.123
Abstract:
The LaY2Ni9.7Mn0.5Al0.3 alloy was prepared by magnetic suspension induction melting method. It was annealed at different temperatures from 1 073 to 1 373 K. The effect of annealing temperature on the phase structure and the electrochemical properties was systematically investigated by X-ray diffraction (XRD), electron probe micro analysis (EPMA), and electrochemical measurements. It was proved that the heat treatment significantly improved the phase uniformity of the alloy. The content of the main phase Ce2Ni7-phase increased first and then decreased with the annealing temperature. At the same time, the maximum discharge capacity, high rate discharge-ability and the cyclic stability of the alloy electrodes all increased first and then decreased, which were consistent with the change of the content of Ce2Ni7 phase. The electrochemical pressure-content-temperature (P-C-T) curves of the alloy electrodes had two hydrogen desorption platforms, and their pressures both increased with the annealing temperature. When the annealing temperature was 1 273 K, the Ce2Ni7 phase content of the alloy was 86.53%(w/w), and the electrochemical properties were the best. The maximum discharge capacity reached to 386.80 mAh·g-1 (60 mA·g-1), the high rate discharge-ability at current density of 900 mA·g-1 (HRD900) was 89.45%, and the maximum capacity retention after 300 cycles (S300) was 72.18% (300 mA·g-1).
The LaY2Ni9.7Mn0.5Al0.3 alloy was prepared by magnetic suspension induction melting method. It was annealed at different temperatures from 1 073 to 1 373 K. The effect of annealing temperature on the phase structure and the electrochemical properties was systematically investigated by X-ray diffraction (XRD), electron probe micro analysis (EPMA), and electrochemical measurements. It was proved that the heat treatment significantly improved the phase uniformity of the alloy. The content of the main phase Ce2Ni7-phase increased first and then decreased with the annealing temperature. At the same time, the maximum discharge capacity, high rate discharge-ability and the cyclic stability of the alloy electrodes all increased first and then decreased, which were consistent with the change of the content of Ce2Ni7 phase. The electrochemical pressure-content-temperature (P-C-T) curves of the alloy electrodes had two hydrogen desorption platforms, and their pressures both increased with the annealing temperature. When the annealing temperature was 1 273 K, the Ce2Ni7 phase content of the alloy was 86.53%(w/w), and the electrochemical properties were the best. The maximum discharge capacity reached to 386.80 mAh·g-1 (60 mA·g-1), the high rate discharge-ability at current density of 900 mA·g-1 (HRD900) was 89.45%, and the maximum capacity retention after 300 cycles (S300) was 72.18% (300 mA·g-1).
2019, 35(6): 1050-1058
doi: 10.11862/CJIC.2019.117
Abstract:
Nickel-rich layered oxide cathode material, Li-NixMnyCo1-x-yO2 (x ≥ 0.8), has a specific capacity as high as 220 mAh·g-1 (x=0.83, 0.1C, 1C=180 mA·g-1) when being charged to 4.5 V (vs Li/Li+), thus it is a very attractive material for the development of high energy density lithium ion batteries. In this work, we have regulated the composition and structure of the cathodeelectrolyte interface (CEI)film on the surface of a nickel-rich layered oxide cathode material (LiNi0.83Mn0.05Co0.12O2) by adding tris(trimethylsilane) phosphite (TMSP) in the electrolyte and investigated how the additive affect the electrochemical performance of the Li‖LiNi0.83Mn0.05Co0.12O2 cell. The TMSP additive helps producing a CEI layer on the surface of the LiNi0.83Mn0.05Co0.12O2 cathode material by electrochemical characterization methods, theoretical calculation, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). The CEI layer wasfound to be thin and uniformly distributed on the cathode surface even after 150 cycles at 1C between 2.8 to 4.5 V (vs Li/Li+), and it was rich in Li2CO3 and Si-O-C, but limited in electrolyte decomposition products, i.e. ROCO2Li and LiF. The CEI layer effectively reduced the polarization of the Li‖LiNi0.83Mn0.05Co0.12O2 cell during cycling which could be due to uniform lithium diffusion that enabled by the uniform CEI thickness, and it was also able to protect the cathode material from structure damaging by suppressing the dissolution of transitional metal ions, resulting in improved high voltage (4.5 V vs Li/Li+) cycling performance and rate capability of the Li‖LiNi0.83Mn0.05Co0.12O2 cells.
Nickel-rich layered oxide cathode material, Li-NixMnyCo1-x-yO2 (x ≥ 0.8), has a specific capacity as high as 220 mAh·g-1 (x=0.83, 0.1C, 1C=180 mA·g-1) when being charged to 4.5 V (vs Li/Li+), thus it is a very attractive material for the development of high energy density lithium ion batteries. In this work, we have regulated the composition and structure of the cathodeelectrolyte interface (CEI)film on the surface of a nickel-rich layered oxide cathode material (LiNi0.83Mn0.05Co0.12O2) by adding tris(trimethylsilane) phosphite (TMSP) in the electrolyte and investigated how the additive affect the electrochemical performance of the Li‖LiNi0.83Mn0.05Co0.12O2 cell. The TMSP additive helps producing a CEI layer on the surface of the LiNi0.83Mn0.05Co0.12O2 cathode material by electrochemical characterization methods, theoretical calculation, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). The CEI layer wasfound to be thin and uniformly distributed on the cathode surface even after 150 cycles at 1C between 2.8 to 4.5 V (vs Li/Li+), and it was rich in Li2CO3 and Si-O-C, but limited in electrolyte decomposition products, i.e. ROCO2Li and LiF. The CEI layer effectively reduced the polarization of the Li‖LiNi0.83Mn0.05Co0.12O2 cell during cycling which could be due to uniform lithium diffusion that enabled by the uniform CEI thickness, and it was also able to protect the cathode material from structure damaging by suppressing the dissolution of transitional metal ions, resulting in improved high voltage (4.5 V vs Li/Li+) cycling performance and rate capability of the Li‖LiNi0.83Mn0.05Co0.12O2 cells.
2019, 35(6): 1059-1064
doi: 10.11862/CJIC.2019.125
Abstract:
Two kinds of polycrystalline powders Ga2-2xO3:2xCr3+ (Ga2O3:xCr) and Y3Ga5-5xO12:5xCr3+ (YGG:xCr) (x=0.01, 0.03, 0.05, 0.07) were synthesized by sol-gel high temperature solid phase synthesis with Ga2O3, Y2O3, Cr(NO3)3 ·9H2O as raw materials and citric acid as complexing agent. The X-ray diffraction (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM) and fluorescence spectroscopy (PL) were used to test and analyze the structure, composition, morphology and fluorescence performance of the powders. XRD and IR showed that all the samples has crystal structure independently on the substituent element; SEM photographs showed that the morphology of the Ga2O3:xCr sample was cylindrical polyhedron, and the morphology of the YGG:xCr powder was in the shape of short rod, both of two phosphor powders had agglomeration. The emission peak of two powders observed at 742 and 740 nm is due to 2E-4A2 transition from Cr3+ ions. The results showed that the fluorescence emission intensity of YGG:xCr was higher, and the emission peak wavelength region is suitable for photosynthesis in plants.
Two kinds of polycrystalline powders Ga2-2xO3:2xCr3+ (Ga2O3:xCr) and Y3Ga5-5xO12:5xCr3+ (YGG:xCr) (x=0.01, 0.03, 0.05, 0.07) were synthesized by sol-gel high temperature solid phase synthesis with Ga2O3, Y2O3, Cr(NO3)3 ·9H2O as raw materials and citric acid as complexing agent. The X-ray diffraction (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM) and fluorescence spectroscopy (PL) were used to test and analyze the structure, composition, morphology and fluorescence performance of the powders. XRD and IR showed that all the samples has crystal structure independently on the substituent element; SEM photographs showed that the morphology of the Ga2O3:xCr sample was cylindrical polyhedron, and the morphology of the YGG:xCr powder was in the shape of short rod, both of two phosphor powders had agglomeration. The emission peak of two powders observed at 742 and 740 nm is due to 2E-4A2 transition from Cr3+ ions. The results showed that the fluorescence emission intensity of YGG:xCr was higher, and the emission peak wavelength region is suitable for photosynthesis in plants.
2019, 35(6): 1065-1075
doi: 10.11862/CJIC.2019.130
Abstract:
Two chiral coordination compounds based on D(-)/L(+)-4-hydroxyphenylglycine (D/L-Hhpg), {[Cu(D-hpg)(phen)(NO3)]·1.5H2O}n (1) and {[Cu(L-hpg)(phen)(NO3)]·2H2O}n (2) (phen=1, 10-phenanthroline) have been syn-thesized and characterized by elemental analysis, infrared spectroscopy, powder X-ray diffraction, single-crystal X-ray diffraction, solid-state CD spectra and TG-DSC analysis. Compounds 1 and 2 are orthorhombic, P212121 chiral space groups. They are 1D chain structure, which is extended into a 3D supramolecular structure by the hydrogen bond. Interestingly, the compounds 1 and 2 exist left-handed or right-handed supramolecular helix chains along the b axis direction by the hydrogen bond respectively, which is extended by the hydrogen bond between coordinated nitrate anion and lattice water. Furthermore, based on the central metal ions of Cu(Ⅱ), further explored the compounds 1 and 2 of electrochemical properties, Analysis of cyclic voltammetry at varying scan rates (0.03 to 0.13 V·s-1) demonstrates a linear relationship between the anode peak current and the scan rate, indicating a surface-controlled electrochemical process.
Two chiral coordination compounds based on D(-)/L(+)-4-hydroxyphenylglycine (D/L-Hhpg), {[Cu(D-hpg)(phen)(NO3)]·1.5H2O}n (1) and {[Cu(L-hpg)(phen)(NO3)]·2H2O}n (2) (phen=1, 10-phenanthroline) have been syn-thesized and characterized by elemental analysis, infrared spectroscopy, powder X-ray diffraction, single-crystal X-ray diffraction, solid-state CD spectra and TG-DSC analysis. Compounds 1 and 2 are orthorhombic, P212121 chiral space groups. They are 1D chain structure, which is extended into a 3D supramolecular structure by the hydrogen bond. Interestingly, the compounds 1 and 2 exist left-handed or right-handed supramolecular helix chains along the b axis direction by the hydrogen bond respectively, which is extended by the hydrogen bond between coordinated nitrate anion and lattice water. Furthermore, based on the central metal ions of Cu(Ⅱ), further explored the compounds 1 and 2 of electrochemical properties, Analysis of cyclic voltammetry at varying scan rates (0.03 to 0.13 V·s-1) demonstrates a linear relationship between the anode peak current and the scan rate, indicating a surface-controlled electrochemical process.
2019, 35(6): 1076-1084
doi: 10.11862/CJIC.2019.101
Abstract:
Five coordination complexes, formulated as {[Zn(btbb)0.5(m-phda)]·0.5H2O}n (1), {[Cd2(btbb)(adtda)2(H2O)]·H2O}n (2), [Mn2(btbb)(tbi)2]n (3), {[Cd(btbb)0.5(3-Nitro-o-bdc)(H2O)]·H2O}n (4) and[Cd2(btbb)(tbi)2]n (5) (btbb=1, 4-bis(2-(4-thiazolyl)benzimidazole-1-ylmethyl)benzene, m-H2phda=m-phenylenediacetic acid, H2adtda=1, 3-adaman-tanedicarboxylic acid, H2tbi=5-tert-butylisophthalic acid, 3-Nitro-o-H2bdc=3-Nitro-1, 2-benzenedicarboxylic acid), have been obtained by hydro(solv)thermal reactions and structurally characterized. Complex 1 exhibits a 1D chain structure containing 22-membered rings. Complex 2 features a 1D chain structure having an 8-membered rings and btbb serves only as an ornament here. Complex 3 is a 1D double chain structure. Complex 4 possesses a 1D chain structure containing 14-membered rings. Complex 5 shows a 1D double chain taking on stair-step. CCDC: 1883643,1;1883644,2;1883645,3;1883646,4;1883647,5.
Five coordination complexes, formulated as {[Zn(btbb)0.5(m-phda)]·0.5H2O}n (1), {[Cd2(btbb)(adtda)2(H2O)]·H2O}n (2), [Mn2(btbb)(tbi)2]n (3), {[Cd(btbb)0.5(3-Nitro-o-bdc)(H2O)]·H2O}n (4) and[Cd2(btbb)(tbi)2]n (5) (btbb=1, 4-bis(2-(4-thiazolyl)benzimidazole-1-ylmethyl)benzene, m-H2phda=m-phenylenediacetic acid, H2adtda=1, 3-adaman-tanedicarboxylic acid, H2tbi=5-tert-butylisophthalic acid, 3-Nitro-o-H2bdc=3-Nitro-1, 2-benzenedicarboxylic acid), have been obtained by hydro(solv)thermal reactions and structurally characterized. Complex 1 exhibits a 1D chain structure containing 22-membered rings. Complex 2 features a 1D chain structure having an 8-membered rings and btbb serves only as an ornament here. Complex 3 is a 1D double chain structure. Complex 4 possesses a 1D chain structure containing 14-membered rings. Complex 5 shows a 1D double chain taking on stair-step. CCDC: 1883643,1;1883644,2;1883645,3;1883646,4;1883647,5.
2019, 35(6): 1085-1092
doi: 10.11862/CJIC.2019.126
Abstract:
A series of luminescence phosphors Sr0.955Al2-xBxSi2O8:0.025Eu2+ (x=0~0.9) were prepared via solid-state reaction in a weak reductive atmosphere. The lattice positions and the luminescent mechanism of Eu2+ in the host were discussed, the effects of B(Ⅲ)-substitution on the host lattices and spectral properties were also investigated. It was found that the complete solid solutions were formed in the whole range of x=0~0.9, as B(Ⅲ) substituted for Al(Ⅲ) entered to SrAl2Si2O8. The lattice parameters (a, b, c) and unit cell volume (V) of phosphors Sr0.955Al2-xBxSi2O8:0.025Eu2+ (x=0~0.9) decreased linearly and lattice parameter (β) increased linearly as the increase of substitution amount of B(Ⅲ). A broad excitation spectrum consisted of four excitation bands, which was in a range of 225~400 nm, and an apparent peak at 350 nm. Full width at half maximum (FWHM) increased from 90 to 102 nm as increase of the substitution amount of B(Ⅲ). The emission spectrum was a broad-band in a range of 370~600 nm, which could be fitted two peaks of 409 and 447 nm, and its apparent peak was at 409 nm. Two fitted peaks were blue shifted and the intensity ratio of the fitted peaks decreased linearly as the increase of the substitution amount of B(Ⅲ)). The coordination number of Sr2+ was 9 in SrAl2Si2O8:Eu2+, which has been confirmed by the experimental results and empirical formula of Van Uitert. The distance between the luminescent center Eu and the ligand O increased due to the Al(Ⅲ) replaced by B(Ⅲ), so that the crystal field strength of Eu2+ decreased, and the 5d energy level split of the luminescent center Eu2+ decreased, the center of gravity of the lowest emission level of Eu2+ was shifted upward, and the two fitted peaks were linearly blue-shifted.
A series of luminescence phosphors Sr0.955Al2-xBxSi2O8:0.025Eu2+ (x=0~0.9) were prepared via solid-state reaction in a weak reductive atmosphere. The lattice positions and the luminescent mechanism of Eu2+ in the host were discussed, the effects of B(Ⅲ)-substitution on the host lattices and spectral properties were also investigated. It was found that the complete solid solutions were formed in the whole range of x=0~0.9, as B(Ⅲ) substituted for Al(Ⅲ) entered to SrAl2Si2O8. The lattice parameters (a, b, c) and unit cell volume (V) of phosphors Sr0.955Al2-xBxSi2O8:0.025Eu2+ (x=0~0.9) decreased linearly and lattice parameter (β) increased linearly as the increase of substitution amount of B(Ⅲ). A broad excitation spectrum consisted of four excitation bands, which was in a range of 225~400 nm, and an apparent peak at 350 nm. Full width at half maximum (FWHM) increased from 90 to 102 nm as increase of the substitution amount of B(Ⅲ). The emission spectrum was a broad-band in a range of 370~600 nm, which could be fitted two peaks of 409 and 447 nm, and its apparent peak was at 409 nm. Two fitted peaks were blue shifted and the intensity ratio of the fitted peaks decreased linearly as the increase of the substitution amount of B(Ⅲ)). The coordination number of Sr2+ was 9 in SrAl2Si2O8:Eu2+, which has been confirmed by the experimental results and empirical formula of Van Uitert. The distance between the luminescent center Eu and the ligand O increased due to the Al(Ⅲ) replaced by B(Ⅲ), so that the crystal field strength of Eu2+ decreased, and the 5d energy level split of the luminescent center Eu2+ decreased, the center of gravity of the lowest emission level of Eu2+ was shifted upward, and the two fitted peaks were linearly blue-shifted.
2019, 35(6): 1093-1100
doi: 10.11862/CJIC.2019.121
Abstract:
A rare tetradecanuclear polyoxofluorovanadate cluster with 1-methylimidazole (L), containing mixed-valence[V14O36F2L2]6- anion, was synthesized and characterized crystallographically. The anion is composed of a special 0D cluster-like skeleton frame, i.e. the ring-shaped[V10O20] ladder, two grafted VO5F and VO3L fragments around the ladder. The density functional theory (DFT) and bond valence sum calculations indicate that the V ion in two grafted VO5F fragments are +4 oxidation state, while other V ions are +5 oxidation state. The frontier orbital analysis shows that the[V14O36F2L2]6- anion, should be chemically active in d orbital of grafted VO5F fragments, while its 2e oxidation species, the[V14O36F2L2]4- anion should be chemically active in the terminal V=O (d-p) π orbital of grafted VO3L fragments. The 2e introduction from[V14O36F2L2]4- to[V14O36F2L2]6- anion leads to the increasing structural stability of the[V10O20] ladder, and at the same time the increasing chemical activity of the grafted VO5F and VO3L fragments, together with a great decrease of energy gap from 1.59 to 0.53 eV.
A rare tetradecanuclear polyoxofluorovanadate cluster with 1-methylimidazole (L), containing mixed-valence[V14O36F2L2]6- anion, was synthesized and characterized crystallographically. The anion is composed of a special 0D cluster-like skeleton frame, i.e. the ring-shaped[V10O20] ladder, two grafted VO5F and VO3L fragments around the ladder. The density functional theory (DFT) and bond valence sum calculations indicate that the V ion in two grafted VO5F fragments are +4 oxidation state, while other V ions are +5 oxidation state. The frontier orbital analysis shows that the[V14O36F2L2]6- anion, should be chemically active in d orbital of grafted VO5F fragments, while its 2e oxidation species, the[V14O36F2L2]4- anion should be chemically active in the terminal V=O (d-p) π orbital of grafted VO3L fragments. The 2e introduction from[V14O36F2L2]4- to[V14O36F2L2]6- anion leads to the increasing structural stability of the[V10O20] ladder, and at the same time the increasing chemical activity of the grafted VO5F and VO3L fragments, together with a great decrease of energy gap from 1.59 to 0.53 eV.
2019, 35(6): 1101-1108
doi: 10.11862/CJIC.2019.133
Abstract:
Magnetic spinel-type MFe2O4 (M=Ca, Mg, Cu and Zn) nanocrystalline powders were successfully prepared by auto-combustion method using a novel amino-based gel. The phase identification, morphology and magnetic properties of as-synthesized powders were studied in detail. The high purity of synthesized MFe2O4 powders was comfirmed by energy dispersive X-ray spectroscopy. Magnetic properties of as-synthesized MFe2O4 nanocrystalline powders were investigated systematically. All the samples presented a rather narrow hysteresis loop, suggesting the soft magnetic features. The saturated magnetization (Ms) of the four ferrites were 2.1, 29.3, 24.1, and 4.2 emu·g-1, respectively, and the residual magnetization (Mr) were 0.2, 2.3, 11.4, and 0.2 emu·g-1, respectively. Mr/Ms values of four ferrite samples were all less than 0.5. Zero-field-cooled and field-cooled magnetic properties of CaFe2O4 and MgFe2O4 samples as two typical ferrites were investigated in detail. The magnetization of CaFe2O4 sample presented an inconsistent variation tendency below 75 K due to the occurrence of magnetic phase transition.
Magnetic spinel-type MFe2O4 (M=Ca, Mg, Cu and Zn) nanocrystalline powders were successfully prepared by auto-combustion method using a novel amino-based gel. The phase identification, morphology and magnetic properties of as-synthesized powders were studied in detail. The high purity of synthesized MFe2O4 powders was comfirmed by energy dispersive X-ray spectroscopy. Magnetic properties of as-synthesized MFe2O4 nanocrystalline powders were investigated systematically. All the samples presented a rather narrow hysteresis loop, suggesting the soft magnetic features. The saturated magnetization (Ms) of the four ferrites were 2.1, 29.3, 24.1, and 4.2 emu·g-1, respectively, and the residual magnetization (Mr) were 0.2, 2.3, 11.4, and 0.2 emu·g-1, respectively. Mr/Ms values of four ferrite samples were all less than 0.5. Zero-field-cooled and field-cooled magnetic properties of CaFe2O4 and MgFe2O4 samples as two typical ferrites were investigated in detail. The magnetization of CaFe2O4 sample presented an inconsistent variation tendency below 75 K due to the occurrence of magnetic phase transition.
2019, 35(6): 1109-1120
doi: 10.11862/CJIC.2019.128
Abstract:
Two newly designed complexes, {[Ni(L1)(n-propanol)]2(OAc)2Ni}·2(n-propanol) (1) and {[Ni(L2)(n-butanol)]2(OAc)2Ni}·2(n-butanol) (2) derived from tetradentate Salamo-type chelating ligands (H2L1=5-methoxy-2, 2'-(ethylenedioxybis(azomethine))diphenol and H2L2=4, 4'-dinitro-2, 2'-(ethylenediyldioxybis(nitrilomethylidyne))diphenol) have been synthesized and characterized by elemental analyses, IR and UV-Vis spectra, Hirshfeld surfaces analyses and single crystal X-ray crystallography. X-ray crystallographic analyses showed that complexes 1 and 2 are all symmetric trinuclear Ni(Ⅱ) complexes. Nickel(Ⅱ) in both 1 and 2 is hexa-coordinated, forming a twisted octahedral geometry. Both crystal structure and Hirshfeld surface analysis indicate that 1 and 2 form stable one-dimensional chain and two-dimensional supramolecular structures, respectively, by intermolecular hydrogen bonding.
Two newly designed complexes, {[Ni(L1)(n-propanol)]2(OAc)2Ni}·2(n-propanol) (1) and {[Ni(L2)(n-butanol)]2(OAc)2Ni}·2(n-butanol) (2) derived from tetradentate Salamo-type chelating ligands (H2L1=5-methoxy-2, 2'-(ethylenedioxybis(azomethine))diphenol and H2L2=4, 4'-dinitro-2, 2'-(ethylenediyldioxybis(nitrilomethylidyne))diphenol) have been synthesized and characterized by elemental analyses, IR and UV-Vis spectra, Hirshfeld surfaces analyses and single crystal X-ray crystallography. X-ray crystallographic analyses showed that complexes 1 and 2 are all symmetric trinuclear Ni(Ⅱ) complexes. Nickel(Ⅱ) in both 1 and 2 is hexa-coordinated, forming a twisted octahedral geometry. Both crystal structure and Hirshfeld surface analysis indicate that 1 and 2 form stable one-dimensional chain and two-dimensional supramolecular structures, respectively, by intermolecular hydrogen bonding.
