The research on the application of X-ray diffraction in the quantitative analysis of Chinese medicines is rare. The main reason is that the technical problems related to the internal standard and the selection of quan...The research on the application of X-ray diffraction in the quantitative analysis of Chinese medicines is rare. The main reason is that the technical problems related to the internal standard and the selection of quantitative peaks are not well solved, and the accuracy and precision of the results are not satisfactory. This study employed the concept of mass absorption coefficient based on the internal standard method, and the full spectrum fitting and quantitative methods were used to solve the above technical problems. The sample was blended. the internal standard substance of zinc oxide was fully ground, and tablets were prepared by positive pressure method. Under certain instrumental conditions, the PXRD pattern was obtained by scanning. The percentage of gypsum fibrosum in Xiaokening tablet was obtained by quantitative analysis of full spectrum fitting internal standard by TOPAS software. The method was investigated by methodology. At the same time, the method was compared by ion chromatography, and SPSS software was used to make a significant t test on the results of the two methods. After the investigation, the average standard recovery rate of CaSO4-2H2O was 99.06%(RSD = 3.02%);and the recovery rate for simulated samples was 96.7%. The method had good specificity. After statistical analysis, there was no significant difference between the new PXRD method and the traditional method of ion chromatography.展开更多
Silicogermanate(JU110)with an interrupted open-framework has been synthesized by using a hydrothermal method using 1,1’-(1,4-phenylenebis(methylene))bis(1-methylpyrrolidin-1-ium)hydroxide as an organic structure-dire...Silicogermanate(JU110)with an interrupted open-framework has been synthesized by using a hydrothermal method using 1,1’-(1,4-phenylenebis(methylene))bis(1-methylpyrrolidin-1-ium)hydroxide as an organic structure-directing agent(OSDA).Silicon and fluoride anions were introduced to the concentrated-gel synthesis system,and different synthetic parameters influencing the synthesis were discussed.The structure of JU110 was characterised by using rotation electron diffraction(RED)and high-resolution powder X-ray diffraction.JU110 crystallizes in the space group Fm2m(No.42)with a=13.9117(2)Å,b=18.2980(3)Åand c=32.7800(6)Å.The structure is constructed by the sti layers found in the STI framework that are pillared by D4R/Ge7 units to form a large cavity,showing 10-ring openings along[100]and 9-ring openings along[110].Thermal stability studies showed that the framework was maintained with the loss of water molecules,but collapsed with the removal of charge-compensating cations.展开更多
Since the first discovery and description of materials,whose structures are not periodic,enormous efforts have been made in studying these aperiodic structures.With these efforts including the development of superspac...Since the first discovery and description of materials,whose structures are not periodic,enormous efforts have been made in studying these aperiodic structures.With these efforts including the development of superspace group theory and structure solution algorithms,numerous incommensurately modulated structures which represent the vast majority of known aperiodic structures have been determined with single crystal X-ray diffraction data.However,the determination of modulated structures remains very difficult for polycrystalline materials.Powder X-ray diffraction and electron microscopy techniques yield remarkable information for polycrystalline materials.By combining these two methods,modulated structures of polycrystalline materials that impede solution by conventional methods can be determined.The power of these methods is illustrated with the examples of the determination of modulated structures of polycrystalline materials.展开更多
The stability of metal–organic frameworks(MOFs)in solutions is of essential importance from the perspectives of scientific research and practical applications.Powder X-ray diffraction(PXRD)with isolated solids is a c...The stability of metal–organic frameworks(MOFs)in solutions is of essential importance from the perspectives of scientific research and practical applications.Powder X-ray diffraction(PXRD)with isolated solids is a common protocol to judge the stability.However,solid-state characterization may lead to ignorance of possible chemical leaching and even partial collapse,and the ignorance may lead to confusing or even false conclusions about stability and relevant properties.展开更多
Aim To prepare and characterize solid dispersions of silymarin with the intention of improving their dissolution properties. Methods The solid dispersions were prepared by the fusion method with polyethylene glycol ...Aim To prepare and characterize solid dispersions of silymarin with the intention of improving their dissolution properties. Methods The solid dispersions were prepared by the fusion method with polyethylene glycol 6000(PEG 6000) as the carrier. Evaluation of the properties of the dispersions was performed using dissolution studies, X ray powder diffraction and Fourier transform infrared (FT IR) spectroscopy. Results The rate of dissolution of silymarin was considerably improved as compared with pure silymarin when formulated in solid dispersions with PEG 6000. The data of the X ray diffraction showed some changes in the parameters of lattice spacing [ d ], peak position and relative intensities. FT IR together with those from X ray diffraction showed the absence of well defined drug polymer interactions. Conclusion The dissolution improvement of poorly soluble silymarin could be illuminated by the changes of the lattice parameters of PEG 6000 and the drug.展开更多
Ce Zr O solid solution was prepared by four different methods, i.e., decomposition of nitrate, coprecipiation, hydroxysuainic acid sol gel as well as citrate sol gel, and characterized by using X ray powder diffr...Ce Zr O solid solution was prepared by four different methods, i.e., decomposition of nitrate, coprecipiation, hydroxysuainic acid sol gel as well as citrate sol gel, and characterized by using X ray powder diffraction, Raman and temperature programmed reduction. The phase composition and the reduction properties of Ce Zr O depend on the preparation method. A cubic Ce 0.5 Zr 0.5 O 2 solid solution can be obtained by using the sol gel method. The Ce Zr O solid solution prepared by using decomposition or coprecipiation was composed of cubic Ce 0.8 Zr 0.2 O 2 and tetragonal Ce 0.2 Zr 0.8 O 2 solid solution. The Ce Zr O solid solution prepared with different methods shows the different reduction properties owing to different phase composition. Results of differential thermal analysis and XRD show that Ce 0.5 Zr 0.5 O 2 solid solution is formed during the decomposition or combustion of the gel.展开更多
The 500℃ isothermal section of the phase diagram of the Cu Be Ag (Cu≥50 at%) ternary system was investigated by X ray powder diffraction. The isothermal section consists of two single phase regions (namely α C...The 500℃ isothermal section of the phase diagram of the Cu Be Ag (Cu≥50 at%) ternary system was investigated by X ray powder diffraction. The isothermal section consists of two single phase regions (namely α Cu and CuBe), two two phase regions (namely α Cu+Ag and CuBe+α Cu) and one three phase region (namely α Cu+Ag+CuBe). The maximum solubility of Be in α Cu and Ag in α Cu are about 6.6 at% and 0.8 at% respectively.展开更多
In this study,a composite material consisting of MXenes(Ti_(3)C_(2)T_(x))and Fe_(3)O_(4)in the ratio of 70:30 w/w%(MXF-30)was synthesized via solvothermal method.The material was characterized using powder X-ray diffr...In this study,a composite material consisting of MXenes(Ti_(3)C_(2)T_(x))and Fe_(3)O_(4)in the ratio of 70:30 w/w%(MXF-30)was synthesized via solvothermal method.The material was characterized using powder X-ray diffraction(PXRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray photoelectron spectroscopy(XPS),and Brunauer-Emmett-Teller measurements(BET)to understand the relationship between the structure and properties for radionuclide removal(^(133)Ba and^(137)Cs).展开更多
Three Pb_(5)Zn_(4)B_(6)O_(18)polymorphs were synthesized by a high temperature solution method.Their structures were determined using single crystal X-ray diffraction and they crystallize in P21/c forα-,γ-Pb_(5)Zn_(...Three Pb_(5)Zn_(4)B_(6)O_(18)polymorphs were synthesized by a high temperature solution method.Their structures were determined using single crystal X-ray diffraction and they crystallize in P21/c forα-,γ-Pb_(5)Zn_(4)B_(6)O_(18)and P1forβ-Pb_(5)Zn_(4)B_(6)O_(18).It is interesting thatα-andβ-Pb_(5)Zn_(4)B_(6)O_(18)crystallize in different space groups with similar structures andα-andγ-Pb_(5)Zn_(4)B_(6)O_(18)crystallize in the same space group with totally different structures.Inα-andβ-Pb_(5)Zn_(4)B_(6)O_(18),ZnO_(4)tetrahedra connect with isolated BO_(3)triangles to construct two dimensional(2D)layers,while inγ-Pb_(5)Zn_(4)B_(6)O_(18),2D Zn-B-O layers change to the 3D framework.The phase transformations of Pb_(5)Zn_(4)B_(6)O_(18)are investigated by the combination of powder X-ray diffraction,thermal behavior analysis and theoretical simulation.Additional functional properties have been investigated using methods such as including UV-vis-NIR diffuse reflectance and IR spectroscopy.展开更多
CsGaS2-mC64 was obtained by reaction of CsN_(3) with stoichiometric amounts of Ga_(2)S_(3) and S at elevated temperatures.The crystal structure of the air-and moisture stable compound was determined from single-crysta...CsGaS2-mC64 was obtained by reaction of CsN_(3) with stoichiometric amounts of Ga_(2)S_(3) and S at elevated temperatures.The crystal structure of the air-and moisture stable compound was determined from single-crystal X-ray diffraction data.The colourless solid crystallizes in the monoclinic space group C_(2)/c(no.15)with the lattice parameters a=10.5718(6)Å,b=10.5708(6)Å,c=16.0847(8)Å,β=99.445(4)°,V=1773.1(2)Å3,and Z=16.The compound crystallizes in the TlGaSe_(2) structure type and features anionic layers 21[Ga_(4)S_(8)^(4−)]consisting of corner-sharing Ga4S10 supertetrahedra.At temperatures above 600℃ an irreversible phase-transition to CsGaS_(2)-mC16 occurs.The phase-transition kinetics were studied using in situ high-temperature X-ray powder diffraction techniques.This transition can only be reversed by using high pressures(>5 GPa at 500℃).The compound was further characterized using Raman-and diffuse reflectance spectroscopy.Chemical bonding was analysed by DFT calculations.展开更多
Phenylacetylene is a detrimental impurity in the polymerisation of styrene,capable of poisoning catalysts even at ppm levels and significantly degrading the quality of polystyrene.The semi-hydrogenation of phenylacety...Phenylacetylene is a detrimental impurity in the polymerisation of styrene,capable of poisoning catalysts even at ppm levels and significantly degrading the quality of polystyrene.The semi-hydrogenation of phenylacetylene to styrene instead of ethylbenzene is,therefore,an important industrial process.We report a novel cerium(Ⅳ)-based metal–organic framework(denoted as Ce-bptc),which comprises{Ce6}clusters bridged by biphenyl-3,3’,5,5’-tetracarboxylate linkers.Ce-bptc serves as an ideal support for palladium nanoparticles and the Pd@Ce-bptc catalyst demonstrates excellent catalytic performance for semi-hydrogenation of phenylacetylene,achieving a selectivity of 93%towards styrene on full conversion under ambient conditions with excellent reusability.In situ synchrotron X-ray powder diffraction and electron paramagnetic resonance spectroscopy reveal the binding domains of phenylacetylene within Cebptc,and details of the reaction mechanism are discussed.展开更多
Sol-gel chemistry,while being extremely established,is to this day not fully understood,and much of the underlying chemistry and mechanisms are yet to be unraveled.Here,we elaborate on the sol-gel chemistry of Cr_(2)G...Sol-gel chemistry,while being extremely established,is to this day not fully understood,and much of the underlying chemistry and mechanisms are yet to be unraveled.Here,we elaborate on the sol-gel chemistry of Cr_(2)GaC,the first layered ternary carbide belonging to the MAX phase family to ever be synthesized using this wet chemical approach.Leveraging a variety of both in-and ex situ characterization techniques,including X-ray and neutron powder diffraction.展开更多
The garnet type phosphors of Eu^(3+)doped Ca_(3)Ga_(2)Ge_(3)O_(12)were synthesized via conventional solid statereaction techniques.The phase purity and luminescence properties of the fabricated phosphors werecharacter...The garnet type phosphors of Eu^(3+)doped Ca_(3)Ga_(2)Ge_(3)O_(12)were synthesized via conventional solid statereaction techniques.The phase purity and luminescence properties of the fabricated phosphors werecharacterized by X-ray powder diffraction,photoluminescence excitation and emission spectra,temperaturedependent emission spectra as well as luminescence decay curves.The phosphors show enhancedred emission from a^(5)D_(0)→^(7)F_(4)transition of Eu^(3+)under the excitation of 394 nm.The unusual^(5)D_(0)→^(7)F_(4)intensity was explained by structural analysis.The emission intensity of the phosphors increases with theconcentration of Eu^(3+)until the quenching concentration of 10 mol%.Excited by a pulsed laser of wavelength610.8 nm,the emission intensity of the^(5)D_(0)→^(7)F_(4)transition increases monotonously as the temperatureincreases in the range of 160–360 K.The temperature dependent fluorescence behavior wasinvestigated.The relative sensitivity reaches the maximum value of 3.66%K−1 at 160 K and reaches 1.04%K^(−1)at 300 K.The results show that the garnet type Ca_(3)Ga_(2)Ge_(3)O_(12):Eu^(3+)phosphor is a promising materialfor the application of optical thermometry.展开更多
In this study,a ratiometric fluorescent probe towards Al^(3+)and F^(−) using a lanthanide metal-organic framework material,Eu-BDC-NH_(2)/TDA,is employed,which is composed of a metal centre Eu^(3+),BDC-NH_(2)and a TDA ...In this study,a ratiometric fluorescent probe towards Al^(3+)and F^(−) using a lanthanide metal-organic framework material,Eu-BDC-NH_(2)/TDA,is employed,which is composed of a metal centre Eu^(3+),BDC-NH_(2)and a TDA dual ligand.This three-dimensional frame structure selectively detects Al^(3+) and F^(−) with a low limit of detection of 0.14 and 0.46μM,respectively,accompanied by a naked-eye identification specificity in the range of 0-1000μM.The detection mechanism of Eu-BDC-NH_(2)/TDA towards Al^(3+)is due to the collapse of the framework and coordination interaction between Al^(3+)and the ligand,and that towards F^(−) is due to a hydrogen-bond interaction,as evidenced by powder X-ray diffraction,Fourier-transform infrared spectroscopy,X-ray photoelectron spectroscopy and N_(2) adsorption-desorption analysis.Furthermore,practical application of Eu-BDC-NH_(2)/TDA is successful for the detection of Al^(3+)and F^(−)in river and tap water samples.展开更多
Persistent stable radical-doped characteristic of naphthalenediimide-based crystalline materials under ambient conditions,even bearing 300℃ high temperature treatment,was studied by UV-Vis-NIR absorption spectroscopy...Persistent stable radical-doped characteristic of naphthalenediimide-based crystalline materials under ambient conditions,even bearing 300℃ high temperature treatment,was studied by UV-Vis-NIR absorption spectroscopy,electron paramagnetic resonance(EPR)spectroscopy and powder X-ray diffraction(PXRD)analyses.On exposure to additional visible light or after-heat treatments,more ultrastable organic radicals can be sharply formed due to the strong and intrinsic electron transfer interactions in the crystalline materials.The significant near-infrared photothermal conversion was directly achieved in these radical-doped crystalline materials without extra chemical modification or photochemical means;furthermore,it can be effectively enhanced by further photo-induction and thermal-activation processes.展开更多
We herein demonstrate the synthesis of a pair of enantiomerically pure Yb^(III) complexes by post-functionalisation of the parent Yb^(III) complex via condensation with an enantiomerically pure chiral amine.The enanti...We herein demonstrate the synthesis of a pair of enantiomerically pure Yb^(III) complexes by post-functionalisation of the parent Yb^(III) complex via condensation with an enantiomerically pure chiral amine.The enantiomeric pair is structurally characterised by single crystal and powder X-ray diffraction,showing that it crystalises in the P2_(1)2_(1)2_(1) Sohncke space group with Flack parameters close to zero,which confirms their enantiopurity.Circular Dichroism(CD)and absorption spectroscopies in the NIR reveal sharp ^(2)F_(7/2)→^(2)F_(5/2) f-f transitions,with gabs values up to 0.07,indicating a chiral environment for the ytterbium centre.Furthermore,a dynamic mechanism with mixing of ligand states is shown to contribute to the CD intensity.X-band pulse Electron Paramagnetic Resonance spectroscopy,on a magnetically dilute single crystal containing 1%of Yb^(III) complexes within the isostructural YIII diamagnetic host,reveals a phase memory time,Tm,of the electronic spin of 600 ns and that it can be coherently manipulated by microwave pulses,as evidenced by Rabi nutations.展开更多
文摘The research on the application of X-ray diffraction in the quantitative analysis of Chinese medicines is rare. The main reason is that the technical problems related to the internal standard and the selection of quantitative peaks are not well solved, and the accuracy and precision of the results are not satisfactory. This study employed the concept of mass absorption coefficient based on the internal standard method, and the full spectrum fitting and quantitative methods were used to solve the above technical problems. The sample was blended. the internal standard substance of zinc oxide was fully ground, and tablets were prepared by positive pressure method. Under certain instrumental conditions, the PXRD pattern was obtained by scanning. The percentage of gypsum fibrosum in Xiaokening tablet was obtained by quantitative analysis of full spectrum fitting internal standard by TOPAS software. The method was investigated by methodology. At the same time, the method was compared by ion chromatography, and SPSS software was used to make a significant t test on the results of the two methods. After the investigation, the average standard recovery rate of CaSO4-2H2O was 99.06%(RSD = 3.02%);and the recovery rate for simulated samples was 96.7%. The method had good specificity. After statistical analysis, there was no significant difference between the new PXRD method and the traditional method of ion chromatography.
基金supported by the National Key Research and Development Program of China(Grant No.2016YFB0701100)the National Natural Science Foundation of China(Grant No.:21320102001 and 21621001)+2 种基金the 111 Project(B17020)financial support from the Swedish Research Council(VR),the Swedish Governmental Agency for Innovation Systems(VINNOVA)the Knut and Alice Wallenberg Foundation through the project grant 3DEM-NATUR.
文摘Silicogermanate(JU110)with an interrupted open-framework has been synthesized by using a hydrothermal method using 1,1’-(1,4-phenylenebis(methylene))bis(1-methylpyrrolidin-1-ium)hydroxide as an organic structure-directing agent(OSDA).Silicon and fluoride anions were introduced to the concentrated-gel synthesis system,and different synthetic parameters influencing the synthesis were discussed.The structure of JU110 was characterised by using rotation electron diffraction(RED)and high-resolution powder X-ray diffraction.JU110 crystallizes in the space group Fm2m(No.42)with a=13.9117(2)Å,b=18.2980(3)Åand c=32.7800(6)Å.The structure is constructed by the sti layers found in the STI framework that are pillared by D4R/Ge7 units to form a large cavity,showing 10-ring openings along[100]and 9-ring openings along[110].Thermal stability studies showed that the framework was maintained with the loss of water molecules,but collapsed with the removal of charge-compensating cations.
基金supported by the Natural Science Foundation of China(21321001 and 21527803)the National Basic Research Program of China(2013CB8933402).
文摘Since the first discovery and description of materials,whose structures are not periodic,enormous efforts have been made in studying these aperiodic structures.With these efforts including the development of superspace group theory and structure solution algorithms,numerous incommensurately modulated structures which represent the vast majority of known aperiodic structures have been determined with single crystal X-ray diffraction data.However,the determination of modulated structures remains very difficult for polycrystalline materials.Powder X-ray diffraction and electron microscopy techniques yield remarkable information for polycrystalline materials.By combining these two methods,modulated structures of polycrystalline materials that impede solution by conventional methods can be determined.The power of these methods is illustrated with the examples of the determination of modulated structures of polycrystalline materials.
基金supported by the National Natural Science Foundation of China(grants 21971069 and 21773070).
文摘The stability of metal–organic frameworks(MOFs)in solutions is of essential importance from the perspectives of scientific research and practical applications.Powder X-ray diffraction(PXRD)with isolated solids is a common protocol to judge the stability.However,solid-state characterization may lead to ignorance of possible chemical leaching and even partial collapse,and the ignorance may lead to confusing or even false conclusions about stability and relevant properties.
文摘Aim To prepare and characterize solid dispersions of silymarin with the intention of improving their dissolution properties. Methods The solid dispersions were prepared by the fusion method with polyethylene glycol 6000(PEG 6000) as the carrier. Evaluation of the properties of the dispersions was performed using dissolution studies, X ray powder diffraction and Fourier transform infrared (FT IR) spectroscopy. Results The rate of dissolution of silymarin was considerably improved as compared with pure silymarin when formulated in solid dispersions with PEG 6000. The data of the X ray diffraction showed some changes in the parameters of lattice spacing [ d ], peak position and relative intensities. FT IR together with those from X ray diffraction showed the absence of well defined drug polymer interactions. Conclusion The dissolution improvement of poorly soluble silymarin could be illuminated by the changes of the lattice parameters of PEG 6000 and the drug.
文摘Ce Zr O solid solution was prepared by four different methods, i.e., decomposition of nitrate, coprecipiation, hydroxysuainic acid sol gel as well as citrate sol gel, and characterized by using X ray powder diffraction, Raman and temperature programmed reduction. The phase composition and the reduction properties of Ce Zr O depend on the preparation method. A cubic Ce 0.5 Zr 0.5 O 2 solid solution can be obtained by using the sol gel method. The Ce Zr O solid solution prepared by using decomposition or coprecipiation was composed of cubic Ce 0.8 Zr 0.2 O 2 and tetragonal Ce 0.2 Zr 0.8 O 2 solid solution. The Ce Zr O solid solution prepared with different methods shows the different reduction properties owing to different phase composition. Results of differential thermal analysis and XRD show that Ce 0.5 Zr 0.5 O 2 solid solution is formed during the decomposition or combustion of the gel.
文摘The 500℃ isothermal section of the phase diagram of the Cu Be Ag (Cu≥50 at%) ternary system was investigated by X ray powder diffraction. The isothermal section consists of two single phase regions (namely α Cu and CuBe), two two phase regions (namely α Cu+Ag and CuBe+α Cu) and one three phase region (namely α Cu+Ag+CuBe). The maximum solubility of Be in α Cu and Ag in α Cu are about 6.6 at% and 0.8 at% respectively.
基金the PhotoMXene project no.3305/03/02 co-funded by the EU Horizon 2020 ResearchInnovation Program under the Program SASPRO2 COFUND Marie-Sklodowska-Curie grant agreement no.945478+1 种基金This research has been also partially supported by the Slovak Research and Development Agency(contract no.APVV-21-0039 and SK-SRB-23-0057)the Scientific Grant Agency of the Slovak Republic under the VEGA project no.1/0319/23.
文摘In this study,a composite material consisting of MXenes(Ti_(3)C_(2)T_(x))and Fe_(3)O_(4)in the ratio of 70:30 w/w%(MXF-30)was synthesized via solvothermal method.The material was characterized using powder X-ray diffraction(PXRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray photoelectron spectroscopy(XPS),and Brunauer-Emmett-Teller measurements(BET)to understand the relationship between the structure and properties for radionuclide removal(^(133)Ba and^(137)Cs).
基金supported by the Key Research Project of Frontier Science of CAS(Grant No.QYZDB-SSW-JSC049)the Western Light Foundation of CAS(Grant 2016-QNXZ-A-2)+2 种基金the Xinjiang Scientific and Technological Innovation Talents Project(Grant No.QN2016YX0339)the Xinjiang International Science&Technology Cooperation Program(Grant No.2017E01014)the Youth Innovation Promotion Association CAS(Grant No.2015353).
文摘Three Pb_(5)Zn_(4)B_(6)O_(18)polymorphs were synthesized by a high temperature solution method.Their structures were determined using single crystal X-ray diffraction and they crystallize in P21/c forα-,γ-Pb_(5)Zn_(4)B_(6)O_(18)and P1forβ-Pb_(5)Zn_(4)B_(6)O_(18).It is interesting thatα-andβ-Pb_(5)Zn_(4)B_(6)O_(18)crystallize in different space groups with similar structures andα-andγ-Pb_(5)Zn_(4)B_(6)O_(18)crystallize in the same space group with totally different structures.Inα-andβ-Pb_(5)Zn_(4)B_(6)O_(18),ZnO_(4)tetrahedra connect with isolated BO_(3)triangles to construct two dimensional(2D)layers,while inγ-Pb_(5)Zn_(4)B_(6)O_(18),2D Zn-B-O layers change to the 3D framework.The phase transformations of Pb_(5)Zn_(4)B_(6)O_(18)are investigated by the combination of powder X-ray diffraction,thermal behavior analysis and theoretical simulation.Additional functional properties have been investigated using methods such as including UV-vis-NIR diffuse reflectance and IR spectroscopy.
文摘CsGaS2-mC64 was obtained by reaction of CsN_(3) with stoichiometric amounts of Ga_(2)S_(3) and S at elevated temperatures.The crystal structure of the air-and moisture stable compound was determined from single-crystal X-ray diffraction data.The colourless solid crystallizes in the monoclinic space group C_(2)/c(no.15)with the lattice parameters a=10.5718(6)Å,b=10.5708(6)Å,c=16.0847(8)Å,β=99.445(4)°,V=1773.1(2)Å3,and Z=16.The compound crystallizes in the TlGaSe_(2) structure type and features anionic layers 21[Ga_(4)S_(8)^(4−)]consisting of corner-sharing Ga4S10 supertetrahedra.At temperatures above 600℃ an irreversible phase-transition to CsGaS_(2)-mC16 occurs.The phase-transition kinetics were studied using in situ high-temperature X-ray powder diffraction techniques.This transition can only be reversed by using high pressures(>5 GPa at 500℃).The compound was further characterized using Raman-and diffuse reflectance spectroscopy.Chemical bonding was analysed by DFT calculations.
基金EPSRC(EP/I011870,EP/V056409,EP/W014521/1),the University of Manchester,the National Science Foundation of China and BNLMS for fundingfunding from the European Research Council(ERC)under the European Union’s Horizon 2020 research and innovation programme(grant agreement No 742401,NANOCHEM and PoC665632).
文摘Phenylacetylene is a detrimental impurity in the polymerisation of styrene,capable of poisoning catalysts even at ppm levels and significantly degrading the quality of polystyrene.The semi-hydrogenation of phenylacetylene to styrene instead of ethylbenzene is,therefore,an important industrial process.We report a novel cerium(Ⅳ)-based metal–organic framework(denoted as Ce-bptc),which comprises{Ce6}clusters bridged by biphenyl-3,3’,5,5’-tetracarboxylate linkers.Ce-bptc serves as an ideal support for palladium nanoparticles and the Pd@Ce-bptc catalyst demonstrates excellent catalytic performance for semi-hydrogenation of phenylacetylene,achieving a selectivity of 93%towards styrene on full conversion under ambient conditions with excellent reusability.In situ synchrotron X-ray powder diffraction and electron paramagnetic resonance spectroscopy reveal the binding domains of phenylacetylene within Cebptc,and details of the reaction mechanism are discussed.
基金supported in part by NNCI-ECCS-1542160.DTA-MS data was gratefully received from Dr Martin Steinbrück and Ulrike Stegmaier at KIT,Germany.Financial support from the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)—Project-ID 405553726—TRR 270 is acknowledgedWe want to acknowledge the Diamond Light Source for beamtime on BL18,DESY(Hamburg,Germany),a member of the Helmholtz Association HGF,for the provision of experimental facilities and the Spallation Neutron Source,a department of Energy Office of Science User Facility operated by the Oak Ridge National Laboratory for providing neutron powder diffraction and total scattering measurements.Parts of this research were carried out at P02.1we would like to thank Alexander Schökel for assistance in using the beamline.We thank DANSCATT(supported by the Danish Agency for Science and Higher Education)for support.M.J.is grateful to the Villum Foundation for financial support through a Villum Young Investigator grant(VKR00015416).
文摘Sol-gel chemistry,while being extremely established,is to this day not fully understood,and much of the underlying chemistry and mechanisms are yet to be unraveled.Here,we elaborate on the sol-gel chemistry of Cr_(2)GaC,the first layered ternary carbide belonging to the MAX phase family to ever be synthesized using this wet chemical approach.Leveraging a variety of both in-and ex situ characterization techniques,including X-ray and neutron powder diffraction.
基金supported by the National Key Research and Development Program of China(Grant No.2016YFB0701001)the National Natural Science Foundation of China(Grant No.11574298 and 61635012).
文摘The garnet type phosphors of Eu^(3+)doped Ca_(3)Ga_(2)Ge_(3)O_(12)were synthesized via conventional solid statereaction techniques.The phase purity and luminescence properties of the fabricated phosphors werecharacterized by X-ray powder diffraction,photoluminescence excitation and emission spectra,temperaturedependent emission spectra as well as luminescence decay curves.The phosphors show enhancedred emission from a^(5)D_(0)→^(7)F_(4)transition of Eu^(3+)under the excitation of 394 nm.The unusual^(5)D_(0)→^(7)F_(4)intensity was explained by structural analysis.The emission intensity of the phosphors increases with theconcentration of Eu^(3+)until the quenching concentration of 10 mol%.Excited by a pulsed laser of wavelength610.8 nm,the emission intensity of the^(5)D_(0)→^(7)F_(4)transition increases monotonously as the temperatureincreases in the range of 160–360 K.The temperature dependent fluorescence behavior wasinvestigated.The relative sensitivity reaches the maximum value of 3.66%K−1 at 160 K and reaches 1.04%K^(−1)at 300 K.The results show that the garnet type Ca_(3)Ga_(2)Ge_(3)O_(12):Eu^(3+)phosphor is a promising materialfor the application of optical thermometry.
基金financially supported by the Natural Science Foundation of Jilin Province(20220101082JC).
文摘In this study,a ratiometric fluorescent probe towards Al^(3+)and F^(−) using a lanthanide metal-organic framework material,Eu-BDC-NH_(2)/TDA,is employed,which is composed of a metal centre Eu^(3+),BDC-NH_(2)and a TDA dual ligand.This three-dimensional frame structure selectively detects Al^(3+) and F^(−) with a low limit of detection of 0.14 and 0.46μM,respectively,accompanied by a naked-eye identification specificity in the range of 0-1000μM.The detection mechanism of Eu-BDC-NH_(2)/TDA towards Al^(3+)is due to the collapse of the framework and coordination interaction between Al^(3+)and the ligand,and that towards F^(−) is due to a hydrogen-bond interaction,as evidenced by powder X-ray diffraction,Fourier-transform infrared spectroscopy,X-ray photoelectron spectroscopy and N_(2) adsorption-desorption analysis.Furthermore,practical application of Eu-BDC-NH_(2)/TDA is successful for the detection of Al^(3+)and F^(−)in river and tap water samples.
基金supported by the National Natural Science Foundation of China(Grant No.22001138,22166028 and 21701170)Jiangxi Provincial Natural Science Foundation(Grant No.20202ACBL213005).
文摘Persistent stable radical-doped characteristic of naphthalenediimide-based crystalline materials under ambient conditions,even bearing 300℃ high temperature treatment,was studied by UV-Vis-NIR absorption spectroscopy,electron paramagnetic resonance(EPR)spectroscopy and powder X-ray diffraction(PXRD)analyses.On exposure to additional visible light or after-heat treatments,more ultrastable organic radicals can be sharply formed due to the strong and intrinsic electron transfer interactions in the crystalline materials.The significant near-infrared photothermal conversion was directly achieved in these radical-doped crystalline materials without extra chemical modification or photochemical means;furthermore,it can be effectively enhanced by further photo-induction and thermal-activation processes.
基金Novo Nordisk Foundation for research grants NNF20OC0065610 Project Grants in the Natural and Technical Sciences 2020,NNF21OC0068806 Research Infrastructure-Large equipment and facilities 2021 financing the Copenhagen Pulse-EPR FacilityNNF21OC0070832 Exploratory Inter-disciplinary Synergy Programme 2021 and NNF23OC0083201 NERD-New Exploratory Research and Discovery 2023BBSRC(BB/R013780/1)for funding.
文摘We herein demonstrate the synthesis of a pair of enantiomerically pure Yb^(III) complexes by post-functionalisation of the parent Yb^(III) complex via condensation with an enantiomerically pure chiral amine.The enantiomeric pair is structurally characterised by single crystal and powder X-ray diffraction,showing that it crystalises in the P2_(1)2_(1)2_(1) Sohncke space group with Flack parameters close to zero,which confirms their enantiopurity.Circular Dichroism(CD)and absorption spectroscopies in the NIR reveal sharp ^(2)F_(7/2)→^(2)F_(5/2) f-f transitions,with gabs values up to 0.07,indicating a chiral environment for the ytterbium centre.Furthermore,a dynamic mechanism with mixing of ligand states is shown to contribute to the CD intensity.X-band pulse Electron Paramagnetic Resonance spectroscopy,on a magnetically dilute single crystal containing 1%of Yb^(III) complexes within the isostructural YIII diamagnetic host,reveals a phase memory time,Tm,of the electronic spin of 600 ns and that it can be coherently manipulated by microwave pulses,as evidenced by Rabi nutations.
