Trifluoroacetic acid(TFA)catalyzed condensation reaction between tetraaminooxacalix[4]arene and N-alkylcarbazole-3,6-dicarbaldehyde in CH_(2)Cl2afforded a single product in 87%–89%yield.Well-defined yet undissolvable...Trifluoroacetic acid(TFA)catalyzed condensation reaction between tetraaminooxacalix[4]arene and N-alkylcarbazole-3,6-dicarbaldehyde in CH_(2)Cl2afforded a single product in 87%–89%yield.Well-defined yet undissolvable1H NMR spectra suggested formation of robust and discrete structures in solution.X-ray single crystal analysis further revealed a giant twisted double-layer chiral macrocycle in the solid state,which was formed from[4+8]condensation of the two reactants via 16 imine bonds.DFT calculations discovered that only the[4+8]twisted product is thermodynamically favorable,which accounts for its highly selective and efficient formation out of a library of many other combinations.展开更多
N-4-（bromobutanoyl）-N＇-（o-, m- and p-tolyl）thioureas 3a, 3b and 3c respectively, were synthesized by the reaction of 4-bromobutanoylisothiocyanate with p-, m- and o-toludine. The products were characterized by IR...N-4-（bromobutanoyl）-N＇-（o-, m- and p-tolyl）thioureas 3a, 3b and 3c respectively, were synthesized by the reaction of 4-bromobutanoylisothiocyanate with p-, m- and o-toludine. The products were characterized by IR, and NMR spectroscopic techniques. The two carbonoylthiourea isomers N-（4-bromobutanoyl）-N＇-（3-methylphenyl）thiourea （3b） and N-（4-bromobutanoyl）-N＇-（4- methylphenyl）thiourea （3c） were obtained in crystalline form by recrystallization from DMSO. X- ray crystallographic studies showed that both compounds 3b and 3c crystallize in triclinic system with space group ofPi. The molecules adopt trans-cis configuration with respect to the positions of 4-bromobutanoyl and tolyl groups respectively, against the thiono C=S bond across their C-N bonds The configuration is attributed by the intrahydrogen bond between the carbonyl oxygen and amide hydrogen atoms. Both crystal structures are stabilized by N-H…S intermolecular hydrogen bonds to form dimers and arranged along the b axis.展开更多
A new neutral ternary samarium complex Sm（Phen）HL3 in which Phen is 1,10-phenanthroline and HL is （1,3-bis（1,3-dimethyl-1H-pyrazol-4-yl）-1,3-propanedione） was synthesized. Molecular structure of this complex was...A new neutral ternary samarium complex Sm（Phen）HL3 in which Phen is 1,10-phenanthroline and HL is （1,3-bis（1,3-dimethyl-1H-pyrazol-4-yl）-1,3-propanedione） was synthesized. Molecular structure of this complex was determined by X-ray diffraction. Under UV-light this complex is demonstrated bright red luminescence （λmax=647 nm）, which was corresponding to the electric dipole 4G5/2→6H9/2 transition in Sm3＋ ion. UV-absorption, excitation and emission spectra of the title compound were investigated.展开更多
The rapid synthesis of 3-bromocarbarole-N-acetic acid was performed using microwave irradiation. Under the optimal conditions the yield was 85.6% . The crystal structure showed that the carboxylic groups form bifurcat...The rapid synthesis of 3-bromocarbarole-N-acetic acid was performed using microwave irradiation. Under the optimal conditions the yield was 85.6% . The crystal structure showed that the carboxylic groups form bifurcated hydrogen bonds and the hydroxyl oxygen atoms serve as proton donors and also acceptor. Each carboxylic group was involved in four hydrogen bonds. The package of crystal was dominated by links of these hydrogen bonds.展开更多
A novel mixed barium(II)/silver(I)/chromium(III) oxalate salt, Ba<sub>0.5</sub>Ag<sub>2</sub>[Cr(C<sub>2</sub>O<sub>4</sub>)<sub>3</sub>]·5H<sub>2...A novel mixed barium(II)/silver(I)/chromium(III) oxalate salt, Ba<sub>0.5</sub>Ag<sub>2</sub>[Cr(C<sub>2</sub>O<sub>4</sub>)<sub>3</sub>]·5H<sub>2</sub>O (1), with open architecture has been synthesized in water and characterized by elemental analysis, vibrational and electronic spectra, and single crystal X-ray structure determination. Compound 1 crystallizes in a monoclinic space group C2/c, with unit cell parameters a = 18.179(3), b = 14.743(2), c = 12.278(2)Å, β = 113.821(3), V = 3010.34(90) Å<sup>3</sup>, Z = 8. The structure is characterized by a network of anionic [Cr(C<sub>2</sub>O<sub>4</sub>)<sub>3</sub>]<sup>3-</sup> units connected through the O atoms of the oxalates to Ba<sup>2+</sup> and Ag<sup>+</sup> sites, forming a three-dimensional coordination polymer with one-dimensional isolated nanochannels parallel to the c axis, and encapsulating hydrogen-bonded vip water molecules. The bulk structure is consolidated by O–H···O bridgings within the nanochannels and by coulombic interactions.展开更多
The polymorphism of nitrofurantoin (NF), 1), the cocrystals of NF:2,2’-bipyridyl = 2:1, 2) and NF: 1,10-phenanthroline = 1:1, 3) have been prepared and characterized. The crystal structure analyses show that there ar...The polymorphism of nitrofurantoin (NF), 1), the cocrystals of NF:2,2’-bipyridyl = 2:1, 2) and NF: 1,10-phenanthroline = 1:1, 3) have been prepared and characterized. The crystal structure analyses show that there are various weak forces among the molecules, such as C/N-H···O, N-H···N hydrogen bond interactions and π···π/lone pair stacking interactions, which play a key role in the assembly of supramolecular networks. A thorough analysis of Hirshfeld surfaces and fingerprint plots facilitates a comparison of intermolecular interactions in 1 - 3, which are crucial in building supramolecular architectures.展开更多
In this paper, we report the ground state properties i.e. electron momentum density and X-ray structure factors of fcc-copper are presented. The Am241 Compton spectrometer, which uses 59.54 keV gamma-rays, has been us...In this paper, we report the ground state properties i.e. electron momentum density and X-ray structure factors of fcc-copper are presented. The Am241 Compton spectrometer, which uses 59.54 keV gamma-rays, has been used for the Compton profile measurement. To compare the experimental data, the Compton profiles within the framework of linear combination of atomic orbitals (LCAO) method using Hartree–Fock (HF), density functional (DF) and hybrid B3PW schemes embodied in the CRYSTAL06 code have been computed. Among the various theoretical calculations, it is found that the present experimental data is in very good agreement with the hybrid B3PW scheme. A real-space analysis of the experimental Compton profile shows the metal-like behavior of copper The structure factors for copper are computed using hybrid B3PW scheme and compared with available experimental and theoretical data.展开更多
The title compound N-4-methyl-1,2,3-thiadiazole-5-carbonyl-N＇-3,5-dichloro-4- （1,1,2,2- tetrafluoroethoxyl）phenyl urea （C13H8Cl2F4N4O3S, Mr = 447.19） has been synthesized from 4-methyl- 1,2,3-thiadiazole-5-carbon...The title compound N-4-methyl-1,2,3-thiadiazole-5-carbonyl-N＇-3,5-dichloro-4- （1,1,2,2- tetrafluoroethoxyl）phenyl urea （C13H8Cl2F4N4O3S, Mr = 447.19） has been synthesized from 4-methyl- 1,2,3-thiadiazole-5-carbonyl chloride as the starting material, and its structure was characterized by proton Nuclear Magnetic Resonance （1H NMR）, Infra Red Spectroscopy （IR）, high-resolution mass spectroscopy （HRMS）, and single-crystal X-ray diffraction. The crystal of the title compound belongs to triclinic, space group Pi with a = 6.0780（8）, b = 11.3760（14）, c = 12.1440（18） A, α = 96.887（7）, β = 91.027（12）, γ= 104.252（13）°, Z = 2, V= 806.98（19）A3, Dc = 1.840 g/cm3, μ= 0.601 mm-1, F（000） = 448, R = 0.0450 and wR = 0.0869. X-ray analysis indicates that the 1,2,3-thiadiazole ring is not coplanar with the phenyl ring, and the dihedral angle is 33.57°. Two intermolecular hydrogen bonds N（2）-H…O（1 ）, S（1 ）…H-C（11）, and three weak intermolecular interactions, C（11）…O（1）, N（1）…O（2） and S…O（1）, are observed. The bioassay results indicate that the title compound has good insecticidal activity against Culex pipiens pallens and good induction activity for tobacco against tobacco mosaic virus which is equal to that of TDL.展开更多
7-（Diethylamino）-3-（4-aminophenyl）coumarin has been synthesized in a new one-pot synthesis by a three-step process starting from 4-（diethylamino）salicylaldehyde and 4-nitrophenylacetonitrile. The product was obt...7-（Diethylamino）-3-（4-aminophenyl）coumarin has been synthesized in a new one-pot synthesis by a three-step process starting from 4-（diethylamino）salicylaldehyde and 4-nitrophenylacetonitrile. The product was obtained in a good yield with a high degree of purity and characterized by NMR, IR and HR-MS. The orange crystals of the title compound were grown from ethyl acetate solution. The solid state structure was established by X-ray crystallography analysis. The crystal belongs to the orthorombic system, space group Pccn with a = 11.1095（5）, b = 33.0187（15）, c = 17.2865（7） A, V= 6341.1（5） A3, C19H20N2O2, Mr = 308.37, ρcalc = 1.292 g·cm^-3, = 0.085 mm^-1, F（000） = 2624, the final R = 0.0480 and wR = 0.1265 （I〉 2σ（I））.展开更多
An “experimental” valence state of metal complexes is sometime different from the “formal” oxidation state, especially in the species having redox active ligands. This difference can be seen in biological system, ...An “experimental” valence state of metal complexes is sometime different from the “formal” oxidation state, especially in the species having redox active ligands. This difference can be seen in biological system, such as iron(IV)-porphyrin π-cation radical in some heme proteins and copper(II)-phenoxyl radical in galactose oxidase (GO). Although structural characterizations of these species by X-ray diffraction methods have been rare due to their stability, some artificial metal-phenoxyl radical complexes have been synthesized and successfully characterized by X-ray crystal structure. In this review, syntheses and X-ray crystal structures of the one-electron oxidized metal-phenolate complexes, metal- phenoxyl radical, and high-valent metal phenolate species are discussed.展开更多
The title compound (C28H27NO5S3, Mr= 553. 69) was prepared bythe reaction of a-thiobenzoylthioformmorholine with diethyl acetylene dicarboxylate.The crystal is monoclinic, space group P21/n with a= 9. 160(3), b= 17. 7...The title compound (C28H27NO5S3, Mr= 553. 69) was prepared bythe reaction of a-thiobenzoylthioformmorholine with diethyl acetylene dicarboxylate.The crystal is monoclinic, space group P21/n with a= 9. 160(3), b= 17. 726(3), c=16. 602(3) A ; β= 100. 375(13)°; V=2651. 4(10) A3, Z=4, Dc= 1. 387 g/cm3, μ(MoKa) =0. 319 mm-1, F(000) =1160, R=0. 0428, wR(F2) =0. 0910 for 2438 observed reflections (I>2(I)). X-ray analysis reveals that interatomic distances for C(5)-C(6), C(13)-C(14) and C(21)-C(22) are 1. 331(4), 1. 351(4), 1. 344(4)A respectively, which show that they are normal C=C double bonds. All S-C bondlengths are similar to typical S-C single bonds (1. 75 - 1. 78 A ). The five-membered ring A (C(5) -C(6) -S(2)-C(13) -S(1) ) (Fig. 1) and six-membered ringB (C(14) -C(15) -C(20) -C(21)-C(22)-S(3) ) (Fig. 1) adopt the flat twist conformation. Furthermore, the morpholine ring adopts chair conformtion.展开更多
The title compound (C28H27NO5S3, Mr= 553. 69) was prepared bythe reaction of a-thiobenzoylthioformmorholine with diethyl acetylene dicarboxylate.The crystal is monoclinic, space group P21/n with a= 9. 160(3), b= 17. 7...The title compound (C28H27NO5S3, Mr= 553. 69) was prepared bythe reaction of a-thiobenzoylthioformmorholine with diethyl acetylene dicarboxylate.The crystal is monoclinic, space group P21/n with a= 9. 160(3), b= 17. 726(3), c=16. 602(3) A ; β= 100. 375(13)°; V=2651. 4(10) A3, Z=4, Dc= 1. 387 g/cm3, μ(MoKa) =0. 319 mm-1, F(000) =1160, R=0. 0428, wR(F2) =0. 0910 for 2438 observed reflections (I】2(I)). X-ray analysis reveals that interatomic distances for C(5)-C(6), C(13)-C(14) and C(21)-C(22) are 1. 331(4), 1. 351(4), 1. 344(4)A respectively, which show that they are normal C=C double bonds. All S-C bondlengths are similar to typical S-C single bonds (1. 75 - 1. 78 A ). The five-membered ring A (C(5) -C(6) -S(2)-C(13) -S(1) ) (Fig. 1) and six-membered ringB (C(14) -C(15) -C(20) -C(21)-C(22)-S(3) ) (Fig. 1) adopt the flat twist conformation. Furthermore, the morpholine ring adopts chair conformtion.展开更多
The development of an analytical method for determining the properties of quantum dots(QDs)is crucial for improving the optical performance of QD-based displays.Therefore,synchrotron-based X-ray photoelectron spectros...The development of an analytical method for determining the properties of quantum dots(QDs)is crucial for improving the optical performance of QD-based displays.Therefore,synchrotron-based X-ray photoelectron spectroscopy(XPS)is designed here to accurately characterize the chemical and structural differences between different QDs.This method enables the determination of the reason for the minimal differences between the optical properties of different QDs depending on the synthesis process,which is difficult to determine using conventional methods alone.Combined with model simulations,the XPS spectra obtained at different photon energies reveal the internal structures and chemical-state distributions of the QDs.In particular,the QD synthesized under optimal conditions demonstrates a relatively lower degree of oxidation of the core and more uniformly stacked ZnSe/ZnS shell layers.The internal structures and chemical-state distributions of QDs are closely related to their optical properties.Finally,the synchrotron-based XPS proposed here can be applied to compare nearly equivalent QDs with slightly different optical properties.展开更多
This study describes the design and performance of a laboratory-based tender X-ray spectrometer for X-ray absorption spectroscopy.The system enables effective absorption spectra to be measured within the 2.0-9.0 keV r...This study describes the design and performance of a laboratory-based tender X-ray spectrometer for X-ray absorption spectroscopy.The system enables effective absorption spectra to be measured within the 2.0-9.0 keV range using Rowland circle geometry;it covers the K edge of 3d transition metals,the L edge of lanthanides,and the M edge of actinides.The spectrometer is configured with a Rowland circle with a diameter of 500 mm and integrates a 250 W liquid metal jet X-ray source,spherical bent crystal analyzer,and energy-resolving silicon drift detector.The X-ray source is installed outside the vacuum chamber and remains fixed,while the analyzer crystals and detector are adjusted to change the Bragg angle,maintaining the Rowland condition.The energy resolution is 0.36-1.30 eV at 2.0-9.0 keV,and the monochromatic flux is approximately 5×10^(5) counts/s at 7040 eV.This study highlights the primary characteristics of the spectrometer and demon-strates its capabilities using selected experimental examples.The successful development of this spectrometer can facilitate research on actinide elements,which are often constrained in synchrotron radiation experiments owing to their radioactivity,thus fostering advancements in related nuclear energy fields.展开更多
In order to investigate the damage tolerance of a metastable Ti-5Al-3V-3Mo-2Cr-2Zr-1Nb-1Fe(Ti5321)alloy with bimodal microstructure using void growth quantification and micromechanical modeling,in situ tensile testing...In order to investigate the damage tolerance of a metastable Ti-5Al-3V-3Mo-2Cr-2Zr-1Nb-1Fe(Ti5321)alloy with bimodal microstructure using void growth quantification and micromechanical modeling,in situ tensile testing was performed during X-ray microtomography experiments.Compared with investigations of surface voids by traditional two-dimensional(2D)methods involving post-mortem characterization,three-dimensional(3D)information on void evolution inside optically opaque samples obtained through X-ray microtomography is essential.The Rice and Tracey model and Huang model were applied to predict void growth and show good agreement with experimental data using calibration of the damage parameterα.The void growth kinetics of Ti5321 with bimodal microstructure was analyzed by comparing theαvalue with that of Ti64 for different microstructure morphologies.The damage mechanism of ductile fracture of Ti5321 with bimodal microstructure is discussed.It was found that the size of the voids apparently increases with the triaxiality of stress.Post-mortem scanning electron microscopy(SEM)was also used to demonstrate this damage mechanism of ductile fracture of Ti5321.展开更多
Pyrrhotite naturally occurs in various superstructures including magnetic(4C)and non-magnetic(5C,6C)types,each with distinct physicochemical properties and flotation behaviors.Challenges in accurately identifying and ...Pyrrhotite naturally occurs in various superstructures including magnetic(4C)and non-magnetic(5C,6C)types,each with distinct physicochemical properties and flotation behaviors.Challenges in accurately identifying and quantifying these superstructures hinder the optimization of pyrrhotite depression in flotation processes.To address this critical issue,synchrotron X-ray powder diffraction(S-XRPD)with Rietveld refinement was employed to quantify the distribution of superstructures in the feed and flotation concentrates of a copper–gold ore.To elucidate the mechanisms influencing depression,density functional theory(DFT)calculations were conducted to explore the electronic structures and surface reactivity of the pyrrhotite superstructures toward the adsorption of water,oxygen and hydroxyl ions(OH-)as dominant species present in the flotation process.S-XRPD analysis revealed that flotation recovery rates of pyrrhotite followed the order of 4C<6C<5C.DFT calculations indicated that the Fe 3d and S 3p orbital band centers exhibited a similar trend relative to the Fermi level with 4C being the closest.The Fe3d band center suggested that the 4C structure possessed a more reactive surface toward the oxygen reduction reaction,promoting the formation of hydrophilic Fe-OH sites.The S 3p band center order also implied that xanthate on the non-magnetic 5C and 6C surfaces could oxidize to dixanthogen,increasing hydrophobicity and floatability,while 4C formed less hydrophobic metal-xanthate complexes.Adsorption energy and charge transfer analyses of water,hydroxyl ions and molecular oxygen further supported the high reactivity and hydrophilic nature of 4C pyrrhotite.The strong bonding with hydroxyl ions indicated enhanced surface passivation by hydrophilic Fe–OOH complexes,aligning with the experimentally observed flotation order(4C<6C<5C).These findings provide a compelling correlation between experimental flotation results and electronic structure calculations,delivering crucial insights for optimizing flotation processes and improving pyrrhotite depression.This breakthrough opens up new opportunities to enhance the efficiency of flotation processes in the mining industry.展开更多
Structural determination plays a pivotal role in chemical research by providing detailed insights into molecular architecture and functionality.Single-crystal X-ray diffraction(SCXRD)is widely regarded as the premier ...Structural determination plays a pivotal role in chemical research by providing detailed insights into molecular architecture and functionality.Single-crystal X-ray diffraction(SCXRD)is widely regarded as the premier technique for achieving precise three-dimensional structural elucidation[1].The persistent challenge of determining atomic-level structures for non-crystalline or conformationally flexible molecules has driven transformative innovations in crystallographic methodologies[2-5].展开更多
Currently,the Al_(2)O_(3)content in the high-alumina slag systems within blast furnaces is generally limited to 16wt%–18.5wt%,making it challenging to overcome this limitation.Unlike most studies that concentrated on...Currently,the Al_(2)O_(3)content in the high-alumina slag systems within blast furnaces is generally limited to 16wt%–18.5wt%,making it challenging to overcome this limitation.Unlike most studies that concentrated on managing the MgO/Al_(2)O_(3)ratio or basicity,this paper explored the effect of equimolar substitution of MgO for CaO on the viscosity and structure of a high-alumina CaO-MgO-Al_(2)O_(3)-SiO_(2)slag system,providing theoretical guidance and data to facilitate the application of high-alumina ores.The results revealed that the viscosity first decreased and then increased with higher MgO substitution,reaching a minimum at 15mol%MgO concentration.Fourier transform infrared spectroscopy(FTIR)results found that the depths of the troughs representing[SiO_(4)]tetrahedra,[AlO_(4)]tetrahedra,and Si-O-Al bending became progressively deeper with increased MgO substitution.Deconvolution of the Raman spectra showed that the average number of bridging oxygens per Si atom and the X_(Q^(3))/X_(Q^(2))(X_(Q^(i))is the molar fraction of Q^(i) unit,and i is the number of bridging oxygens in a[SiO_(4)]tetrahedral unit)ratio increased from 2.30 and 1.02 to 2.52 and 2.14,respectively,indicating a progressive polymerization of the silicate structure.X-ray photoelectron spectroscopy(XPS)results highlighted that non-bridging oxygen content decreased from 77.97mol% to 63.41mol% with increasing MgO concentration,whereas bridging oxygen and free oxygen contents increased.Structural analysis demonstrated a gradual increase in the polymerization degree of the tetrahedral structure with the increase in MgO substitution.However,bond strength is another important factor affecting the slag viscosity.The occurrence of a viscosity minimum can be attributed to the complex evolution of bond strengths of non-bridging oxygens generated during depolymerization of the[SiO_(4)]and[AlO_(4)]tetrahedral structures by CaO and MgO.展开更多
The layout and characteristics of the hard X-ray spectroscopy beamline(BL11B)at the Shanghai synchrotron radiation facility are described herein.BL11B is a bending-magnet beamline dedicated to conventional and millise...The layout and characteristics of the hard X-ray spectroscopy beamline(BL11B)at the Shanghai synchrotron radiation facility are described herein.BL11B is a bending-magnet beamline dedicated to conventional and millisecond-scale quick-scanning X-ray absorption fine structures.It is equipped with a cylindrical collimating mirror,a double-crystal monochromator comprising Si(111)and Si(311),a channel-cut quick-scanning Si(111)monochromator,a toroidal focusing mirror,and a high harmonics rejection mirror.It can provide 5-30 keV of X-rays with a photon flux of~5×10^(11)photons/s and an energy resolution of~1.31×10^(-4)at 10 keV.The performance of the beamline can satisfy the demands of users in the fields of catalysis,materials,and environmental science.This paper presents an overview of the beamline design and a detailed description of its performance and capabilities.展开更多
With vigorous developments in nanotechnology,the elaborate regulation of microstructure shows attractive potential in the design of electromagnetic wave absorbers.Herein,a hierarchical porous structure and composite h...With vigorous developments in nanotechnology,the elaborate regulation of microstructure shows attractive potential in the design of electromagnetic wave absorbers.Herein,a hierarchical porous structure and composite heterogeneous interface are constructed successfully to optimize the electromagnetic loss capacity.The macro–micro-synergistic graphene aerogel formed by the ice template‑assisted 3D printing strategy is cut by silicon carbide nanowires(SiC_(nws))grown in situ,while boron nitride(BN)interfacial structure is introduced on graphene nanoplates.The unique composite structure forces multiple scattering of incident EMWs,ensuring the combined effects of interfacial polarization,conduction networks,and magnetic-dielectric synergy.Therefore,the as-prepared composites present a minimum reflection loss value of−37.8 dB and a wide effective absorption bandwidth(EAB)of 9.2 GHz(from 8.8 to 18.0 GHz)at 2.5 mm.Besides,relying on the intrinsic high-temperature resistance of SiC_(nws) and BN,the EAB also remains above 5.0 GHz after annealing in air environment at 600℃ for 10 h.展开更多
基金supported by the National Natural Science Foundation of China(Nos.21971223 and 21772178)。
文摘Trifluoroacetic acid(TFA)catalyzed condensation reaction between tetraaminooxacalix[4]arene and N-alkylcarbazole-3,6-dicarbaldehyde in CH_(2)Cl2afforded a single product in 87%–89%yield.Well-defined yet undissolvable1H NMR spectra suggested formation of robust and discrete structures in solution.X-ray single crystal analysis further revealed a giant twisted double-layer chiral macrocycle in the solid state,which was formed from[4+8]condensation of the two reactants via 16 imine bonds.DFT calculations discovered that only the[4+8]twisted product is thermodynamically favorable,which accounts for its highly selective and efficient formation out of a library of many other combinations.
基金the Ministry of Higher Education of Malaysia and Universiti Kebangsaan Malaysia for the research grant DIP-2014-016 and FRGS/1/2013/ST01/UKM/03/4the Ministry of Higher Education of Libya for the scholarship
文摘N-4-（bromobutanoyl）-N＇-（o-, m- and p-tolyl）thioureas 3a, 3b and 3c respectively, were synthesized by the reaction of 4-bromobutanoylisothiocyanate with p-, m- and o-toludine. The products were characterized by IR, and NMR spectroscopic techniques. The two carbonoylthiourea isomers N-（4-bromobutanoyl）-N＇-（3-methylphenyl）thiourea （3b） and N-（4-bromobutanoyl）-N＇-（4- methylphenyl）thiourea （3c） were obtained in crystalline form by recrystallization from DMSO. X- ray crystallographic studies showed that both compounds 3b and 3c crystallize in triclinic system with space group ofPi. The molecules adopt trans-cis configuration with respect to the positions of 4-bromobutanoyl and tolyl groups respectively, against the thiono C=S bond across their C-N bonds The configuration is attributed by the intrahydrogen bond between the carbonyl oxygen and amide hydrogen atoms. Both crystal structures are stabilized by N-H…S intermolecular hydrogen bonds to form dimers and arranged along the b axis.
文摘A new neutral ternary samarium complex Sm（Phen）HL3 in which Phen is 1,10-phenanthroline and HL is （1,3-bis（1,3-dimethyl-1H-pyrazol-4-yl）-1,3-propanedione） was synthesized. Molecular structure of this complex was determined by X-ray diffraction. Under UV-light this complex is demonstrated bright red luminescence （λmax=647 nm）, which was corresponding to the electric dipole 4G5/2→6H9/2 transition in Sm3＋ ion. UV-absorption, excitation and emission spectra of the title compound were investigated.
文摘The rapid synthesis of 3-bromocarbarole-N-acetic acid was performed using microwave irradiation. Under the optimal conditions the yield was 85.6% . The crystal structure showed that the carboxylic groups form bifurcated hydrogen bonds and the hydroxyl oxygen atoms serve as proton donors and also acceptor. Each carboxylic group was involved in four hydrogen bonds. The package of crystal was dominated by links of these hydrogen bonds.
文摘A novel mixed barium(II)/silver(I)/chromium(III) oxalate salt, Ba<sub>0.5</sub>Ag<sub>2</sub>[Cr(C<sub>2</sub>O<sub>4</sub>)<sub>3</sub>]·5H<sub>2</sub>O (1), with open architecture has been synthesized in water and characterized by elemental analysis, vibrational and electronic spectra, and single crystal X-ray structure determination. Compound 1 crystallizes in a monoclinic space group C2/c, with unit cell parameters a = 18.179(3), b = 14.743(2), c = 12.278(2)Å, β = 113.821(3), V = 3010.34(90) Å<sup>3</sup>, Z = 8. The structure is characterized by a network of anionic [Cr(C<sub>2</sub>O<sub>4</sub>)<sub>3</sub>]<sup>3-</sup> units connected through the O atoms of the oxalates to Ba<sup>2+</sup> and Ag<sup>+</sup> sites, forming a three-dimensional coordination polymer with one-dimensional isolated nanochannels parallel to the c axis, and encapsulating hydrogen-bonded vip water molecules. The bulk structure is consolidated by O–H···O bridgings within the nanochannels and by coulombic interactions.
文摘The polymorphism of nitrofurantoin (NF), 1), the cocrystals of NF:2,2’-bipyridyl = 2:1, 2) and NF: 1,10-phenanthroline = 1:1, 3) have been prepared and characterized. The crystal structure analyses show that there are various weak forces among the molecules, such as C/N-H···O, N-H···N hydrogen bond interactions and π···π/lone pair stacking interactions, which play a key role in the assembly of supramolecular networks. A thorough analysis of Hirshfeld surfaces and fingerprint plots facilitates a comparison of intermolecular interactions in 1 - 3, which are crucial in building supramolecular architectures.
文摘In this paper, we report the ground state properties i.e. electron momentum density and X-ray structure factors of fcc-copper are presented. The Am241 Compton spectrometer, which uses 59.54 keV gamma-rays, has been used for the Compton profile measurement. To compare the experimental data, the Compton profiles within the framework of linear combination of atomic orbitals (LCAO) method using Hartree–Fock (HF), density functional (DF) and hybrid B3PW schemes embodied in the CRYSTAL06 code have been computed. Among the various theoretical calculations, it is found that the present experimental data is in very good agreement with the hybrid B3PW scheme. A real-space analysis of the experimental Compton profile shows the metal-like behavior of copper The structure factors for copper are computed using hybrid B3PW scheme and compared with available experimental and theoretical data.
基金funded in part by grants from the National Natural Science Foundation of China (20872071)the Natural Science Foundation of Tianjin (10JCZDJC17500)+3 种基金the National Key Project for Basic Research (2010CB126105)the National Key Technology Research and Development Program (2011BAE06B02)the Foundation of Achievements Transformation and Spreading of Tianjin Agricultural Science and Technology(201002250)Tianjin Key Technology Research and Development Program (11ZCGYNC00100)
文摘The title compound N-4-methyl-1,2,3-thiadiazole-5-carbonyl-N＇-3,5-dichloro-4- （1,1,2,2- tetrafluoroethoxyl）phenyl urea （C13H8Cl2F4N4O3S, Mr = 447.19） has been synthesized from 4-methyl- 1,2,3-thiadiazole-5-carbonyl chloride as the starting material, and its structure was characterized by proton Nuclear Magnetic Resonance （1H NMR）, Infra Red Spectroscopy （IR）, high-resolution mass spectroscopy （HRMS）, and single-crystal X-ray diffraction. The crystal of the title compound belongs to triclinic, space group Pi with a = 6.0780（8）, b = 11.3760（14）, c = 12.1440（18） A, α = 96.887（7）, β = 91.027（12）, γ= 104.252（13）°, Z = 2, V= 806.98（19）A3, Dc = 1.840 g/cm3, μ= 0.601 mm-1, F（000） = 448, R = 0.0450 and wR = 0.0869. X-ray analysis indicates that the 1,2,3-thiadiazole ring is not coplanar with the phenyl ring, and the dihedral angle is 33.57°. Two intermolecular hydrogen bonds N（2）-H…O（1 ）, S（1 ）…H-C（11）, and three weak intermolecular interactions, C（11）…O（1）, N（1）…O（2） and S…O（1）, are observed. The bioassay results indicate that the title compound has good insecticidal activity against Culex pipiens pallens and good induction activity for tobacco against tobacco mosaic virus which is equal to that of TDL.
基金The"Groupement Franco-Ukrainien en Chimie Moléculaire"(GDRI)and the Embassy of France in Kyiv are gratefully acknowledged for financial support
文摘7-（Diethylamino）-3-（4-aminophenyl）coumarin has been synthesized in a new one-pot synthesis by a three-step process starting from 4-（diethylamino）salicylaldehyde and 4-nitrophenylacetonitrile. The product was obtained in a good yield with a high degree of purity and characterized by NMR, IR and HR-MS. The orange crystals of the title compound were grown from ethyl acetate solution. The solid state structure was established by X-ray crystallography analysis. The crystal belongs to the orthorombic system, space group Pccn with a = 11.1095（5）, b = 33.0187（15）, c = 17.2865（7） A, V= 6341.1（5） A3, C19H20N2O2, Mr = 308.37, ρcalc = 1.292 g·cm^-3, = 0.085 mm^-1, F（000） = 2624, the final R = 0.0480 and wR = 0.1265 （I〉 2σ（I））.
文摘An “experimental” valence state of metal complexes is sometime different from the “formal” oxidation state, especially in the species having redox active ligands. This difference can be seen in biological system, such as iron(IV)-porphyrin π-cation radical in some heme proteins and copper(II)-phenoxyl radical in galactose oxidase (GO). Although structural characterizations of these species by X-ray diffraction methods have been rare due to their stability, some artificial metal-phenoxyl radical complexes have been synthesized and successfully characterized by X-ray crystal structure. In this review, syntheses and X-ray crystal structures of the one-electron oxidized metal-phenolate complexes, metal- phenoxyl radical, and high-valent metal phenolate species are discussed.
文摘The title compound (C28H27NO5S3, Mr= 553. 69) was prepared bythe reaction of a-thiobenzoylthioformmorholine with diethyl acetylene dicarboxylate.The crystal is monoclinic, space group P21/n with a= 9. 160(3), b= 17. 726(3), c=16. 602(3) A ; β= 100. 375(13)°; V=2651. 4(10) A3, Z=4, Dc= 1. 387 g/cm3, μ(MoKa) =0. 319 mm-1, F(000) =1160, R=0. 0428, wR(F2) =0. 0910 for 2438 observed reflections (I>2(I)). X-ray analysis reveals that interatomic distances for C(5)-C(6), C(13)-C(14) and C(21)-C(22) are 1. 331(4), 1. 351(4), 1. 344(4)A respectively, which show that they are normal C=C double bonds. All S-C bondlengths are similar to typical S-C single bonds (1. 75 - 1. 78 A ). The five-membered ring A (C(5) -C(6) -S(2)-C(13) -S(1) ) (Fig. 1) and six-membered ringB (C(14) -C(15) -C(20) -C(21)-C(22)-S(3) ) (Fig. 1) adopt the flat twist conformation. Furthermore, the morpholine ring adopts chair conformtion.
文摘The title compound (C28H27NO5S3, Mr= 553. 69) was prepared bythe reaction of a-thiobenzoylthioformmorholine with diethyl acetylene dicarboxylate.The crystal is monoclinic, space group P21/n with a= 9. 160(3), b= 17. 726(3), c=16. 602(3) A ; β= 100. 375(13)°; V=2651. 4(10) A3, Z=4, Dc= 1. 387 g/cm3, μ(MoKa) =0. 319 mm-1, F(000) =1160, R=0. 0428, wR(F2) =0. 0910 for 2438 observed reflections (I】2(I)). X-ray analysis reveals that interatomic distances for C(5)-C(6), C(13)-C(14) and C(21)-C(22) are 1. 331(4), 1. 351(4), 1. 344(4)A respectively, which show that they are normal C=C double bonds. All S-C bondlengths are similar to typical S-C single bonds (1. 75 - 1. 78 A ). The five-membered ring A (C(5) -C(6) -S(2)-C(13) -S(1) ) (Fig. 1) and six-membered ringB (C(14) -C(15) -C(20) -C(21)-C(22)-S(3) ) (Fig. 1) adopt the flat twist conformation. Furthermore, the morpholine ring adopts chair conformtion.
基金Advanced Light Source,which is a DOE Office of Science User Facility under contract no.DE-AC02-05CH11231the Basque Government for funding through a PhD Fellowship(Grant no.PRE_2018_2_0285)+1 种基金through Egonlabur Travel Fellowship(Grant no.EP_2018_1_0004)partially supported by an Early Career Award in the Condensed Phase and Interfacial Molecular Science Program,in the Chemical Sciences Geosciences and Biosciences Division of the Office of Basic Energy Sciences of the U.S.Department of Energy under Contract No.DE-AC02-05CH11231.
文摘The development of an analytical method for determining the properties of quantum dots(QDs)is crucial for improving the optical performance of QD-based displays.Therefore,synchrotron-based X-ray photoelectron spectroscopy(XPS)is designed here to accurately characterize the chemical and structural differences between different QDs.This method enables the determination of the reason for the minimal differences between the optical properties of different QDs depending on the synthesis process,which is difficult to determine using conventional methods alone.Combined with model simulations,the XPS spectra obtained at different photon energies reveal the internal structures and chemical-state distributions of the QDs.In particular,the QD synthesized under optimal conditions demonstrates a relatively lower degree of oxidation of the core and more uniformly stacked ZnSe/ZnS shell layers.The internal structures and chemical-state distributions of QDs are closely related to their optical properties.Finally,the synchrotron-based XPS proposed here can be applied to compare nearly equivalent QDs with slightly different optical properties.
基金supported by the Instrument and Equipment Development Program of the Chinese Academy of Science(Grant No.YJKYYQ20180066)the National Natural Science Foundation of China(No.22227809)+2 种基金the Shanghai Science and Technology Innovation Action Plan(No.22142200300)the Science and Technology Talents Program of the Shanghai Institute of Applied Physics(No.SINAP-KJZX-202204)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA 0400000).
文摘This study describes the design and performance of a laboratory-based tender X-ray spectrometer for X-ray absorption spectroscopy.The system enables effective absorption spectra to be measured within the 2.0-9.0 keV range using Rowland circle geometry;it covers the K edge of 3d transition metals,the L edge of lanthanides,and the M edge of actinides.The spectrometer is configured with a Rowland circle with a diameter of 500 mm and integrates a 250 W liquid metal jet X-ray source,spherical bent crystal analyzer,and energy-resolving silicon drift detector.The X-ray source is installed outside the vacuum chamber and remains fixed,while the analyzer crystals and detector are adjusted to change the Bragg angle,maintaining the Rowland condition.The energy resolution is 0.36-1.30 eV at 2.0-9.0 keV,and the monochromatic flux is approximately 5×10^(5) counts/s at 7040 eV.This study highlights the primary characteristics of the spectrometer and demon-strates its capabilities using selected experimental examples.The successful development of this spectrometer can facilitate research on actinide elements,which are often constrained in synchrotron radiation experiments owing to their radioactivity,thus fostering advancements in related nuclear energy fields.
基金supported by the China Postdoctoral Science Foundation(No.2022M720399).
文摘In order to investigate the damage tolerance of a metastable Ti-5Al-3V-3Mo-2Cr-2Zr-1Nb-1Fe(Ti5321)alloy with bimodal microstructure using void growth quantification and micromechanical modeling,in situ tensile testing was performed during X-ray microtomography experiments.Compared with investigations of surface voids by traditional two-dimensional(2D)methods involving post-mortem characterization,three-dimensional(3D)information on void evolution inside optically opaque samples obtained through X-ray microtomography is essential.The Rice and Tracey model and Huang model were applied to predict void growth and show good agreement with experimental data using calibration of the damage parameterα.The void growth kinetics of Ti5321 with bimodal microstructure was analyzed by comparing theαvalue with that of Ti64 for different microstructure morphologies.The damage mechanism of ductile fracture of Ti5321 with bimodal microstructure is discussed.It was found that the size of the voids apparently increases with the triaxiality of stress.Post-mortem scanning electron microscopy(SEM)was also used to demonstrate this damage mechanism of ductile fracture of Ti5321.
基金supported by the Australian Research Council Linkage Project(No.LP200200717)co sponsored by Newmont Corporation(United States)and Vega Industries(India)+1 种基金the Powder Diffraction Beamline at the Australia’s Nuclear Science and Technology Organisation(No.PDR19870),Australiathe Centre for Microscopy and Microanalysis at the University of Queensland(No.1366),Australia。
文摘Pyrrhotite naturally occurs in various superstructures including magnetic(4C)and non-magnetic(5C,6C)types,each with distinct physicochemical properties and flotation behaviors.Challenges in accurately identifying and quantifying these superstructures hinder the optimization of pyrrhotite depression in flotation processes.To address this critical issue,synchrotron X-ray powder diffraction(S-XRPD)with Rietveld refinement was employed to quantify the distribution of superstructures in the feed and flotation concentrates of a copper–gold ore.To elucidate the mechanisms influencing depression,density functional theory(DFT)calculations were conducted to explore the electronic structures and surface reactivity of the pyrrhotite superstructures toward the adsorption of water,oxygen and hydroxyl ions(OH-)as dominant species present in the flotation process.S-XRPD analysis revealed that flotation recovery rates of pyrrhotite followed the order of 4C<6C<5C.DFT calculations indicated that the Fe 3d and S 3p orbital band centers exhibited a similar trend relative to the Fermi level with 4C being the closest.The Fe3d band center suggested that the 4C structure possessed a more reactive surface toward the oxygen reduction reaction,promoting the formation of hydrophilic Fe-OH sites.The S 3p band center order also implied that xanthate on the non-magnetic 5C and 6C surfaces could oxidize to dixanthogen,increasing hydrophobicity and floatability,while 4C formed less hydrophobic metal-xanthate complexes.Adsorption energy and charge transfer analyses of water,hydroxyl ions and molecular oxygen further supported the high reactivity and hydrophilic nature of 4C pyrrhotite.The strong bonding with hydroxyl ions indicated enhanced surface passivation by hydrophilic Fe–OOH complexes,aligning with the experimentally observed flotation order(4C<6C<5C).These findings provide a compelling correlation between experimental flotation results and electronic structure calculations,delivering crucial insights for optimizing flotation processes and improving pyrrhotite depression.This breakthrough opens up new opportunities to enhance the efficiency of flotation processes in the mining industry.
文摘Structural determination plays a pivotal role in chemical research by providing detailed insights into molecular architecture and functionality.Single-crystal X-ray diffraction(SCXRD)is widely regarded as the premier technique for achieving precise three-dimensional structural elucidation[1].The persistent challenge of determining atomic-level structures for non-crystalline or conformationally flexible molecules has driven transformative innovations in crystallographic methodologies[2-5].
基金financially supported by the National Natural Science Foundation of China(Nos.52425408 and 52304345)the Fundamental Research Funds for the Central Universities,China(No.2023CDJXY-016)the Postdoctoral Science Foundation of Chongqing(No.CSTB2023NSCQ-BHX0174)。
文摘Currently,the Al_(2)O_(3)content in the high-alumina slag systems within blast furnaces is generally limited to 16wt%–18.5wt%,making it challenging to overcome this limitation.Unlike most studies that concentrated on managing the MgO/Al_(2)O_(3)ratio or basicity,this paper explored the effect of equimolar substitution of MgO for CaO on the viscosity and structure of a high-alumina CaO-MgO-Al_(2)O_(3)-SiO_(2)slag system,providing theoretical guidance and data to facilitate the application of high-alumina ores.The results revealed that the viscosity first decreased and then increased with higher MgO substitution,reaching a minimum at 15mol%MgO concentration.Fourier transform infrared spectroscopy(FTIR)results found that the depths of the troughs representing[SiO_(4)]tetrahedra,[AlO_(4)]tetrahedra,and Si-O-Al bending became progressively deeper with increased MgO substitution.Deconvolution of the Raman spectra showed that the average number of bridging oxygens per Si atom and the X_(Q^(3))/X_(Q^(2))(X_(Q^(i))is the molar fraction of Q^(i) unit,and i is the number of bridging oxygens in a[SiO_(4)]tetrahedral unit)ratio increased from 2.30 and 1.02 to 2.52 and 2.14,respectively,indicating a progressive polymerization of the silicate structure.X-ray photoelectron spectroscopy(XPS)results highlighted that non-bridging oxygen content decreased from 77.97mol% to 63.41mol% with increasing MgO concentration,whereas bridging oxygen and free oxygen contents increased.Structural analysis demonstrated a gradual increase in the polymerization degree of the tetrahedral structure with the increase in MgO substitution.However,bond strength is another important factor affecting the slag viscosity.The occurrence of a viscosity minimum can be attributed to the complex evolution of bond strengths of non-bridging oxygens generated during depolymerization of the[SiO_(4)]and[AlO_(4)]tetrahedral structures by CaO and MgO.
文摘The layout and characteristics of the hard X-ray spectroscopy beamline(BL11B)at the Shanghai synchrotron radiation facility are described herein.BL11B is a bending-magnet beamline dedicated to conventional and millisecond-scale quick-scanning X-ray absorption fine structures.It is equipped with a cylindrical collimating mirror,a double-crystal monochromator comprising Si(111)and Si(311),a channel-cut quick-scanning Si(111)monochromator,a toroidal focusing mirror,and a high harmonics rejection mirror.It can provide 5-30 keV of X-rays with a photon flux of~5×10^(11)photons/s and an energy resolution of~1.31×10^(-4)at 10 keV.The performance of the beamline can satisfy the demands of users in the fields of catalysis,materials,and environmental science.This paper presents an overview of the beamline design and a detailed description of its performance and capabilities.
基金sponsored by National Natural Science Foundation of China(No.52302121,No.52203386)Shanghai Sailing Program(No.23YF1454700)+1 种基金Shanghai Natural Science Foundation(No.23ZR1472700)Shanghai Post-doctoral Excellent Program(No.2022664).
文摘With vigorous developments in nanotechnology,the elaborate regulation of microstructure shows attractive potential in the design of electromagnetic wave absorbers.Herein,a hierarchical porous structure and composite heterogeneous interface are constructed successfully to optimize the electromagnetic loss capacity.The macro–micro-synergistic graphene aerogel formed by the ice template‑assisted 3D printing strategy is cut by silicon carbide nanowires(SiC_(nws))grown in situ,while boron nitride(BN)interfacial structure is introduced on graphene nanoplates.The unique composite structure forces multiple scattering of incident EMWs,ensuring the combined effects of interfacial polarization,conduction networks,and magnetic-dielectric synergy.Therefore,the as-prepared composites present a minimum reflection loss value of−37.8 dB and a wide effective absorption bandwidth(EAB)of 9.2 GHz(from 8.8 to 18.0 GHz)at 2.5 mm.Besides,relying on the intrinsic high-temperature resistance of SiC_(nws) and BN,the EAB also remains above 5.0 GHz after annealing in air environment at 600℃ for 10 h.
