A series of CeO2/SiO2 and SixCe1–xO2 complex oxides supported on an activated Al2TiO5-TiO2-SiO2 complex phase (ATS) ceramics were prepared by step impregnation and co-impregnation methods, and characterized by N2-BET...A series of CeO2/SiO2 and SixCe1–xO2 complex oxides supported on an activated Al2TiO5-TiO2-SiO2 complex phase (ATS) ceramics were prepared by step impregnation and co-impregnation methods, and characterized by N2-BET, XRD, SEM and NH3-TPD techniques. The effects of reaction temperature, CeO2/SiO2 loadings and Si/Ce molar ratio on the granular catalysts for NO selective catalytic reduction with ammonia (NH3-SCR) were studied. Results indicated that both CeO2/SiO2/ATS and CeO2/ATS catalysts showed the same ac...展开更多
A cerium-triethanolamine complex was obtained by the reaction of cerium(III) nitrate and triethanolamine in ethanol solution. Spontaneous oxidation of cerium(III) to cerium(IV) by oxygen occurred during the reaction. ...A cerium-triethanolamine complex was obtained by the reaction of cerium(III) nitrate and triethanolamine in ethanol solution. Spontaneous oxidation of cerium(III) to cerium(IV) by oxygen occurred during the reaction. The complex was crystalline and soluble in water. Nanosized ceria (CeO2) particles could be prepared via hydrolysis of the complex in aqueous solution, and the extent of agglomeration of particles increased with the increase in temperature for hydrolysis. Under the low temperature of 25 oC, mon...展开更多
Three Ce 4+ complexes Ce(p tert butylcalixarene)·(dmf) 4·H 2O (complex A), Ce(p tert butylcalixarene) 2·(dmf) 10 (complex B) and Ce(p tert butylcalixarene)·(dmf) 4 (complex C) w...Three Ce 4+ complexes Ce(p tert butylcalixarene)·(dmf) 4·H 2O (complex A), Ce(p tert butylcalixarene) 2·(dmf) 10 (complex B) and Ce(p tert butylcalixarene)·(dmf) 4 (complex C) were prepared from N,N dimethylforamide (dmf) solution of Ce(NO 3) 3. Their thermal stability, optical properties and coordination features were investigated with thermogravimetric and differential thermal analysis, ultraviolet and visible spectrophotometer, fluorescence spectrophotometer, infrared spectroscopy, and 1H NMR spectrometer. In the solvents of C 6H 6, 1,2 dichloroethane and dmf, complexes A and B can exhibit a ligand to metal charge transfer transition lying in ca. 20000 cm -1 in the electronic spectra. Complex A displays a dimeric structure in C 6D 6 solution. Ce 4+ ions in the complexes are coordinated by phenolic groups of the ligands, oxygen atoms of dmf molecules, and / or OH - ions.展开更多
A new cerium complex, （C7H8）[Ce（C7H3NO5）2（H2O）3]·2H2O or （C7Hs）[Ce（HChel）2· （H2O）3]·2H2O （1, H3Chel = 4-hydroxypyridine-2,6-dicarboxylic （chelidamic） acid）, has been prepared by the hydr...A new cerium complex, （C7H8）[Ce（C7H3NO5）2（H2O）3]·2H2O or （C7Hs）[Ce（HChel）2· （H2O）3]·2H2O （1, H3Chel = 4-hydroxypyridine-2,6-dicarboxylic （chelidamic） acid）, has been prepared by the hydrothermal reaction, and its crystal structure was determined based on single-crystal diffraction data. Compound I crystallizes in monoclinic, space group P21/c with a = 12.4267（9）, b = 10.8195（7）, c = 19.5650（13）A, β = 92.898（3）°, V = 2627.2（3） A^3, Dc = 1.733 g/cm^3, Z = 4, Mr = 685.55, μ = 1.809 mm^-1, λ（MoKa） = 0.71073A and F（000） = 1372. The final R = 0.0455 and wR = 0.1984 for 5983 observed reflections with I 〉 2σ（I）, and R = 0.0490 and wR = 0.2053 for all data. Complex 1 contains one cerium ion, two chelidamic acid ligands, three coordinated water molecules, one discrete toluene molecule, and two discrete water molecules. The Ce（IV） ion is nine-coordinate with the coordination polyhedron made up of four oxygen atoms and two nitrogen atoms from two tridentate chelating chelidamic acid ligands, and three coordinated water molecules. A three-dimensional network is formed by the H-bonds. Moreover, optical properties are investigated and the results show that this complex has sharp optical absorption at 221,396 and 571 nm but no marked fluorescent emission.展开更多
Sensitization of metal-centered forbidden transitions is of great significance.Solid MnII-based phosphors with d-d forbidden transition sensitized by CeIIIwith d-f allowed transition are promising light conversion mat...Sensitization of metal-centered forbidden transitions is of great significance.Solid MnII-based phosphors with d-d forbidden transition sensitized by CeIIIwith d-f allowed transition are promising light conversion materials,but the energy transfer mechanism in CeIII-MnIIis still in dispute for the uncertainty of distances between metal centers.Herein,for the first time,we explored the energy transfer mechanism in two well-designed luminescent heteronuclear complexes with clear crystal structures,i.e.,Ce-N8-Mn and Ce-N2O6-Mn(N8=1,4,7,10,13,16,21,24-octaazabicyclo[8.8.8]hexacosane;N2O6=4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane).Short distances between metal centers facilitate efficient energy transfer from CeIIIto MnIIin both complexes,resulting in high photoluminescence quantum yield up to unity.After systematic study of the two heteronuclear complexes as well as two reference complexes Ce(N8)Br3and Ce(N2O6)Br3,we concluded that dipole-quadrupole interaction is the dominant energy transfer mechanism in the heteronuclear complexes.展开更多
The cerium iron complex oxides oxygen carrier was prepared by the co-precipitation method. The reactions between methane and lattice oxygen from the complex oxides were investigated in a fixed micro-reactor system. Th...The cerium iron complex oxides oxygen carrier was prepared by the co-precipitation method. The reactions between methane and lattice oxygen from the complex oxides were investigated in a fixed micro-reactor system. The reduced oxygen carder could be re-oxidized by air and its initial state could be restored. The characterizations of the oxygen carders were studied using XRD, O2-TPD, and H2-TPR. The results showed that the bulk lattice oxygen of CeO2-Fe2O3 was found to be suitable for the partial oxidation of methane to synthesis gas. There were two kinds of oxygen species on the oxygen carrier： the stronger oxygen species that was responsible for the complete oxidation of methane, and the weaker oxygen species （bulk lattice oxygen） that was responsible for the selective oxidation of methane to CO and H2 at a higher temperature. Then, the lost bulk lattice oxygen could be selectively supplemented by air re-oxidation at an appropriate reaction condition. CeFeO3 appeared on the oxygen carrier after 10 successive redox cycles, however, it was not bad for the selectivity of CO and H2.展开更多
The complex with the formula [CeFe(CN)(6)(H2O)(3)]. 2H(2)O was synthesized and structurally characterized. It crystallizes in hexagonal, space group P3, a = 0.75320(10) nm, b = 0.75320(10) nm, c = 1.4374(3) nm, gamma ...The complex with the formula [CeFe(CN)(6)(H2O)(3)]. 2H(2)O was synthesized and structurally characterized. It crystallizes in hexagonal, space group P3, a = 0.75320(10) nm, b = 0.75320(10) nm, c = 1.4374(3) nm, gamma = 120 degrees, V = 0.7062(2) nm(3), Z = 3, Be = 3.048 Mg .m(-3), F(000) = 606, mu = 6.346 mm(-1), T = 293(2) K, R-1 = 0.0169, wR(2) = 0.0459. The structure is a three-dimensional network containing open channels formed by the nine-coordinated CeN6(H2O)(3) groups and octahedral FeC6 groups through the cyanide linkages. Magnetic susceptibility measurements in the temperature range of 5.1 similar to 300 It show an antiferromagnetic interaction between the Ce3+ and Fe3+ ions.展开更多
[Ce(CH3COO)2(NO3) (phen)]2, Mr=1000. 84. The crystal is monoclinic, lattice type C-centered, space group C2/m, with a=15. 444 (6), b= 12. 273(5), c=12. 776(5) A, β= 131. 89(2)°, Z= 2, Dc= 1, 844 g/cm3, μ(MoKa)=...[Ce(CH3COO)2(NO3) (phen)]2, Mr=1000. 84. The crystal is monoclinic, lattice type C-centered, space group C2/m, with a=15. 444 (6), b= 12. 273(5), c=12. 776(5) A, β= 131. 89(2)°, Z= 2, Dc= 1, 844 g/cm3, μ(MoKa)=25. 69 cm-1, F(000)=980. 00, V= 1802 (1 ) A, R=0.024, Rw=0. 032. Themolecule of the complex is a dimer with C2h symmetry and the molecular center lies onthe special position 2/m. The Ce(Ⅲ) ion is nine-coordianted to one bidentate nitrategroup, five oxygen atoms of acetates and two nitrogen atoms of 1, 10-phenanthroine(phen).展开更多
The complex of rare earth with ciprofloxacin has been synthesized and characterized by means of x-ray single crystal diffraction. The structure features of the complex are decribed.
Polymeric cerium nitrate complex with 1,4 bis(phenylsulfinyl)butane (bphsb) [Ce(bphsb) 2(NO 3) 3] n (1) was synthesized and characterized. The crystal structure of the complex indicated that the ligand bphsb ...Polymeric cerium nitrate complex with 1,4 bis(phenylsulfinyl)butane (bphsb) [Ce(bphsb) 2(NO 3) 3] n (1) was synthesized and characterized. The crystal structure of the complex indicated that the ligand bphsb and cerium(Ⅲ) ion form a polymeric double bridge chain complex involving 18 membered macrometallocycles. Each cerium ion is coordinated by ten O atoms in a distorted 4,4 bicapped square antiprism. In the complex the disulfoxide ligand acts as bis monodentate O ligand bridging metal centers.展开更多
Luminescent lanthanide cerium(III) compounds have gathered increasing research interest in both inorganic phosphors and functional molecular complexes. Cerium(III) exhibits broad double-peak emission originating from ...Luminescent lanthanide cerium(III) compounds have gathered increasing research interest in both inorganic phosphors and functional molecular complexes. Cerium(III) exhibits broad double-peak emission originating from 5d excited state 2D3/2 to 4f ground states 2F7/2 and 2F5/2. It is vital to adjust the bandwidth of the emission for different applications like lighting and display, while no regulation between these two peaks in Ce(III) emitters has been reported hitherto. In this work, novel heavy-atom-induced narrow emission is observed in luminescent Ce(III) complexes by adopting imidodiphosphinate ligand with different chalcogen-coordinating sites from O to S, Se, and Te. Not only a new Ce(III) complex with orange–red emission beyond the traditional emission color regions of Ce(III) was obtained, but also the ratio of the two peaks was systematically tuned to achieve the narrowest emission from Ce(III) with a full width at half maximum of 42 nm. Time-dependent density functional theory calculations ascribe the tuning of emission spectra to centroid shift and simultaneously provide the orbital contribution values of different chalcogen atoms to the emission excited state. By extending the coordination atoms from classic oxygen and nitrogen to heavier and softer elements, these results give new insight into luminescence properties and mechanisms of Ce(III) emission.展开更多
Doublet emission from open-shell molecules has attracted widespread attention owing to its fundamental importance and potential applications in various fields.However,compared to traditional closed-shell molecules,mol...Doublet emission from open-shell molecules has attracted widespread attention owing to its fundamental importance and potential applications in various fields.However,compared to traditional closed-shell molecules,molecular design and photoluminescence mechanism of doublet emission materials are less studied.Herein,we demonstrate a new lanthanide complex cerium(Ⅲ)tris[4-benzoylphenyl-tris(pyrazolyl)borate][Ce(PhCOPhTp)_(3)]with a novel luminescence mechanism of double delayed doublet emission(DDDE).By delicately designing a ligand with two proper metastable triplet excited states,two channels for energy transfer between doublet and triplet excited states were constructed,thereby activating two delayed doublet emissions,that is,DDDE.This work demonstrates a unique multi-energy-level model in lanthanide Ce(Ⅲ)complex and would inspire new insight into the design of novel and functional doublet luminescence materials.展开更多
基金Project supported by the National High-Tech Research and Development Program of China (2009AA05Z313)National Natural Science Foundation of China (50872052)Foundation of Jiangsu Province of China for College Postgraduate Students in Innovation Engineering (CX07B_083z)
文摘A series of CeO2/SiO2 and SixCe1–xO2 complex oxides supported on an activated Al2TiO5-TiO2-SiO2 complex phase (ATS) ceramics were prepared by step impregnation and co-impregnation methods, and characterized by N2-BET, XRD, SEM and NH3-TPD techniques. The effects of reaction temperature, CeO2/SiO2 loadings and Si/Ce molar ratio on the granular catalysts for NO selective catalytic reduction with ammonia (NH3-SCR) were studied. Results indicated that both CeO2/SiO2/ATS and CeO2/ATS catalysts showed the same ac...
基金Project supported by the Provincal Major Science and Technology Special Projects of Zhejiang Province (2006 C11172)
文摘A cerium-triethanolamine complex was obtained by the reaction of cerium(III) nitrate and triethanolamine in ethanol solution. Spontaneous oxidation of cerium(III) to cerium(IV) by oxygen occurred during the reaction. The complex was crystalline and soluble in water. Nanosized ceria (CeO2) particles could be prepared via hydrolysis of the complex in aqueous solution, and the extent of agglomeration of particles increased with the increase in temperature for hydrolysis. Under the low temperature of 25 oC, mon...
文摘Three Ce 4+ complexes Ce(p tert butylcalixarene)·(dmf) 4·H 2O (complex A), Ce(p tert butylcalixarene) 2·(dmf) 10 (complex B) and Ce(p tert butylcalixarene)·(dmf) 4 (complex C) were prepared from N,N dimethylforamide (dmf) solution of Ce(NO 3) 3. Their thermal stability, optical properties and coordination features were investigated with thermogravimetric and differential thermal analysis, ultraviolet and visible spectrophotometer, fluorescence spectrophotometer, infrared spectroscopy, and 1H NMR spectrometer. In the solvents of C 6H 6, 1,2 dichloroethane and dmf, complexes A and B can exhibit a ligand to metal charge transfer transition lying in ca. 20000 cm -1 in the electronic spectra. Complex A displays a dimeric structure in C 6D 6 solution. Ce 4+ ions in the complexes are coordinated by phenolic groups of the ligands, oxygen atoms of dmf molecules, and / or OH - ions.
基金supported by the NNSFC (20801026)the Nanchang Hangkong University Doctoral Foundation (EA200702136)
文摘A new cerium complex, （C7H8）[Ce（C7H3NO5）2（H2O）3]·2H2O or （C7Hs）[Ce（HChel）2· （H2O）3]·2H2O （1, H3Chel = 4-hydroxypyridine-2,6-dicarboxylic （chelidamic） acid）, has been prepared by the hydrothermal reaction, and its crystal structure was determined based on single-crystal diffraction data. Compound I crystallizes in monoclinic, space group P21/c with a = 12.4267（9）, b = 10.8195（7）, c = 19.5650（13）A, β = 92.898（3）°, V = 2627.2（3） A^3, Dc = 1.733 g/cm^3, Z = 4, Mr = 685.55, μ = 1.809 mm^-1, λ（MoKa） = 0.71073A and F（000） = 1372. The final R = 0.0455 and wR = 0.1984 for 5983 observed reflections with I 〉 2σ（I）, and R = 0.0490 and wR = 0.2053 for all data. Complex 1 contains one cerium ion, two chelidamic acid ligands, three coordinated water molecules, one discrete toluene molecule, and two discrete water molecules. The Ce（IV） ion is nine-coordinate with the coordination polyhedron made up of four oxygen atoms and two nitrogen atoms from two tridentate chelating chelidamic acid ligands, and three coordinated water molecules. A three-dimensional network is formed by the H-bonds. Moreover, optical properties are investigated and the results show that this complex has sharp optical absorption at 221,396 and 571 nm but no marked fluorescent emission.
基金financial support from the National Key R&D Program of China(Nos.2022YFB3503702,2023YFB3506901,2021YFB3501800)the National Natural Science Foundation of China(Nos.92156016,62104013,22071003)。
文摘Sensitization of metal-centered forbidden transitions is of great significance.Solid MnII-based phosphors with d-d forbidden transition sensitized by CeIIIwith d-f allowed transition are promising light conversion materials,but the energy transfer mechanism in CeIII-MnIIis still in dispute for the uncertainty of distances between metal centers.Herein,for the first time,we explored the energy transfer mechanism in two well-designed luminescent heteronuclear complexes with clear crystal structures,i.e.,Ce-N8-Mn and Ce-N2O6-Mn(N8=1,4,7,10,13,16,21,24-octaazabicyclo[8.8.8]hexacosane;N2O6=4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane).Short distances between metal centers facilitate efficient energy transfer from CeIIIto MnIIin both complexes,resulting in high photoluminescence quantum yield up to unity.After systematic study of the two heteronuclear complexes as well as two reference complexes Ce(N8)Br3and Ce(N2O6)Br3,we concluded that dipole-quadrupole interaction is the dominant energy transfer mechanism in the heteronuclear complexes.
基金the National Natural Science Foundation of China (50574046)National Natural Science Foundation of Major Research Projects (90610035)+1 种基金Natural Science Foundation of Yunnan Province (2004E0058Q)High School Doctoral Subject Special Science and Research Foundation of Ministry of Education (20040674005)
文摘The cerium iron complex oxides oxygen carrier was prepared by the co-precipitation method. The reactions between methane and lattice oxygen from the complex oxides were investigated in a fixed micro-reactor system. The reduced oxygen carder could be re-oxidized by air and its initial state could be restored. The characterizations of the oxygen carders were studied using XRD, O2-TPD, and H2-TPR. The results showed that the bulk lattice oxygen of CeO2-Fe2O3 was found to be suitable for the partial oxidation of methane to synthesis gas. There were two kinds of oxygen species on the oxygen carrier： the stronger oxygen species that was responsible for the complete oxidation of methane, and the weaker oxygen species （bulk lattice oxygen） that was responsible for the selective oxidation of methane to CO and H2 at a higher temperature. Then, the lost bulk lattice oxygen could be selectively supplemented by air re-oxidation at an appropriate reaction condition. CeFeO3 appeared on the oxygen carrier after 10 successive redox cycles, however, it was not bad for the selectivity of CO and H2.
文摘The complex with the formula [CeFe(CN)(6)(H2O)(3)]. 2H(2)O was synthesized and structurally characterized. It crystallizes in hexagonal, space group P3, a = 0.75320(10) nm, b = 0.75320(10) nm, c = 1.4374(3) nm, gamma = 120 degrees, V = 0.7062(2) nm(3), Z = 3, Be = 3.048 Mg .m(-3), F(000) = 606, mu = 6.346 mm(-1), T = 293(2) K, R-1 = 0.0169, wR(2) = 0.0459. The structure is a three-dimensional network containing open channels formed by the nine-coordinated CeN6(H2O)(3) groups and octahedral FeC6 groups through the cyanide linkages. Magnetic susceptibility measurements in the temperature range of 5.1 similar to 300 It show an antiferromagnetic interaction between the Ce3+ and Fe3+ ions.
文摘[Ce(CH3COO)2(NO3) (phen)]2, Mr=1000. 84. The crystal is monoclinic, lattice type C-centered, space group C2/m, with a=15. 444 (6), b= 12. 273(5), c=12. 776(5) A, β= 131. 89(2)°, Z= 2, Dc= 1, 844 g/cm3, μ(MoKa)=25. 69 cm-1, F(000)=980. 00, V= 1802 (1 ) A, R=0.024, Rw=0. 032. Themolecule of the complex is a dimer with C2h symmetry and the molecular center lies onthe special position 2/m. The Ce(Ⅲ) ion is nine-coordianted to one bidentate nitrategroup, five oxygen atoms of acetates and two nitrogen atoms of 1, 10-phenanthroine(phen).
文摘The complex of rare earth with ciprofloxacin has been synthesized and characterized by means of x-ray single crystal diffraction. The structure features of the complex are decribed.
文摘Polymeric cerium nitrate complex with 1,4 bis(phenylsulfinyl)butane (bphsb) [Ce(bphsb) 2(NO 3) 3] n (1) was synthesized and characterized. The crystal structure of the complex indicated that the ligand bphsb and cerium(Ⅲ) ion form a polymeric double bridge chain complex involving 18 membered macrometallocycles. Each cerium ion is coordinated by ten O atoms in a distorted 4,4 bicapped square antiprism. In the complex the disulfoxide ligand acts as bis monodentate O ligand bridging metal centers.
基金supported by the National Natural Science Foundation of China(U23A20593,12234001,22071003,62104013,and 92156016)the National Key R&D Program of China(2021YFB3501800,2021YFB3500400,2022YFB3503700,2022YFF0710001,and 2023YFB3506901).
文摘Luminescent lanthanide cerium(III) compounds have gathered increasing research interest in both inorganic phosphors and functional molecular complexes. Cerium(III) exhibits broad double-peak emission originating from 5d excited state 2D3/2 to 4f ground states 2F7/2 and 2F5/2. It is vital to adjust the bandwidth of the emission for different applications like lighting and display, while no regulation between these two peaks in Ce(III) emitters has been reported hitherto. In this work, novel heavy-atom-induced narrow emission is observed in luminescent Ce(III) complexes by adopting imidodiphosphinate ligand with different chalcogen-coordinating sites from O to S, Se, and Te. Not only a new Ce(III) complex with orange–red emission beyond the traditional emission color regions of Ce(III) was obtained, but also the ratio of the two peaks was systematically tuned to achieve the narrowest emission from Ce(III) with a full width at half maximum of 42 nm. Time-dependent density functional theory calculations ascribe the tuning of emission spectra to centroid shift and simultaneously provide the orbital contribution values of different chalcogen atoms to the emission excited state. By extending the coordination atoms from classic oxygen and nitrogen to heavier and softer elements, these results give new insight into luminescence properties and mechanisms of Ce(III) emission.
基金financial support from the National Key R&D Program of China(grant nos.2023YFB3506901,2021YFB3501800,2021YFB3500400,2022YFB3503700,and 2022YFF0710001)the National Natural Science Foundation of China(grant nos.22071003,62104013,92156016,and U23A20593).
文摘Doublet emission from open-shell molecules has attracted widespread attention owing to its fundamental importance and potential applications in various fields.However,compared to traditional closed-shell molecules,molecular design and photoluminescence mechanism of doublet emission materials are less studied.Herein,we demonstrate a new lanthanide complex cerium(Ⅲ)tris[4-benzoylphenyl-tris(pyrazolyl)borate][Ce(PhCOPhTp)_(3)]with a novel luminescence mechanism of double delayed doublet emission(DDDE).By delicately designing a ligand with two proper metastable triplet excited states,two channels for energy transfer between doublet and triplet excited states were constructed,thereby activating two delayed doublet emissions,that is,DDDE.This work demonstrates a unique multi-energy-level model in lanthanide Ce(Ⅲ)complex and would inspire new insight into the design of novel and functional doublet luminescence materials.
