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1.
Lithium rubidium borate (LiRbB4O7) single crystal has been grown by the Czochralski method. Crystalline perfection and optical homogeneity of the grown LiRbB4O7 crystal are analyzed by high resolution X-ray diffraction and birefringence interferometric technique, respectively. Third order nonlinear optical parameters of LiRbB4O7 crystal are determined by Z-scan experimental technique. The nonlinear refractive index (n2) and third-order nonlinear optical susceptibility (χ3) are estimated to be −4.935 × 10−11 cm2/W and 2.719 × 10−7 esu, respectively. The measured (n2) value reveals the self-focusing nature of LiRbB4O7 crystal. 相似文献
2.
The new compounds U3Co12−xX4 with X=Si, Ge were prepared by direct solidification of the corresponding liquid phase, followed by subsequent annealing at 1173 K. Single crystal X-ray diffraction carried out at room temperature showed that they crystallize with the hexagonal space group P63/mmc (no.194) and the unit-cell parameters a=8.130(5), c=8.537(5) Å and a=8.256(1), c=8.608(1) Å for the silicide and germanide, respectively. Their crystal structure derives from the EuMg5.2 structure type, and is closely related to the Sc3Ni11Si4 and Gd3Ru4−xAl12+x types. For the present compounds, no substitution mechanisms have been observed, the partial occupancy of one Co site results from the presence of vacancies, only. The homogeneity ranges, evaluated by energy dispersive spectroscopy analysis, extend from x=0.0(2) to 0.3(2) and from x=0.0(2) to 1.0(2) for U3Co12−xSi4 and U3Co12−xGe4, respectively. The electronic properties of both compounds were investigated by means of DC magnetic susceptibility and DC electrical resistivity measurements. The U3Co12−xX4 compounds are both Pauli paramagnets with their electrical resistivity best described as poor metallic or dirty metallic behavior. 相似文献
3.
The transparent TiO2 thin films coated on fused-SiO2 substrates were prepared by the sol–gel method and spin-coating technique. Effects of calcination temperature on crystal
structure, grain size, surface texture, and light transmittance of the films were investigated. After calcining at 600–1,200 °C,
the thicknesses of the TiO2 films were all around 80 nm and the molecular structures of the films were anatase, even at 1,200 °C. The calcined TiO2 films had the ultraviolet light (wavelength 200–400 nm) transmittances of ≤29% and the visible light (wavelength 400–800 nm)
transmittance of ≥72%. By photocatalytically decomposing the methylene blue (MB) in water, the photocatalytic activities of
the TiO2 thin films were measured and represented using the characteristic time constant (τ) for the MB degradation. While the films
prepared at 1,000 and 1,200 °C photodecomposed about 54 mol% of the MB in water (the corresponding τ ≈ 14.8 h) after exposing to 365-nm UV light for 12 h, the films prepared at 600 and 800 °C had smaller τ (≈9.0 h) and photodecomposed
about 74 mol% of the MB in water at the same testing conditions. 相似文献
4.
LI XiangJun ZHENG Na HU ZhongBo & YUAN ZhuoBin College of Chemistry Chemical Engineering Graduate University of Chinese Academy of Sciences Beijing China 《中国科学B辑(英文版)》2009,(8)
A series of Nd1-yDyyFe11-xTiMx(M=Mo,Si) alloys have been prepared by arc melting and studied by X-ray diffraction and neutron diffraction.All samples are found to crystallize in the ThMn12-type structure.The lattice parameters a and c and unit cell volume V of Nd0.5Dy0.5Fe11-xTiMox alloys increase linearly with increasing content of Mo(x),while the lattice parameters a and c and unit cell volume V of Nd0.5Dy0.5Fe11-xTiSix alloys decrease linearly with increasing content of Si(x).In NdyDy1-yFe11-xTiMx(M=Mo,S... 相似文献
5.
Single crystals of a new calcium(II) complex of benzilic acid, [Ca(C14H11O3)2(C14H12O3)2] have been successfully grown by gel diffusion technique at room temperature. Single crystal X-ray diffraction study reveals that the compound belongs to orthorhombic system with space group Fddd. The adjacent CaO8 units are linked via O–H–O interaction to form one dimensional polymeric chains. The extensive hydrogen bonding interactions lead to a supramolecular structure. The grown crystals were further characterized by elemental analysis, FT-IR, UV–Visible, thermogravimetric, powder X-ray diffraction and solid state photoluminescence studies. 相似文献
6.
Sara Busi Jarmo Ropponen Jussi Valkonen Kari Rissanen 《Journal of solid state chemistry》2004,177(10):3757-3767
Series of new aromatic R2R′2N+Br− (R=benzyl, 4-methylbenzyl, 2-phenylethyl, 3-phenylpropyl; R′=ethyl, methyl, isopropyl) or RR′2NH+Br−-type (R=benzyl, R′=isopropyl) quaternary ammonium bromides were prepared by using novel synthetic route in which a formamide (N,N-diethylformamide, N,N-dimethylformamide, N,N-diisopropylformamide) is treated with aralkyl halide in presence of a weak base. The compounds were characterized by 1H-NMR and 13C-NMR spectroscopy and mass spectrometry. Structures of the crystalline compounds were determined by X-ray single crystal diffraction, and in addition the powder diffraction method was used to study the structural similarities between the single crystal and microcrystalline bulk material. Three of the compounds crystallized in monoclinic, two in orthorhombic and one in triclinic crystal system, showing ion pairs, which are interconnected by weak hydrogen bonds and weak π-π interactions between the phenyl rings. Three of the compounds appeared as viscous oil or waxes. Finally, TG/DTA and DSC methods were used to analyze thermal properties of the prepared compounds. The lowest melting points were obtained for diethyldi-(2-phenylethyl)ammonium bromide (122.2 °C) and for diethyldi-(3-phenylpropyl)-ammonium bromide (109.1 °C). In general, decomposition of the compounds started at 170-190 °C without identifiable cleavages, thus liquid ranges of 30-70 °C were observed for some of the compounds. 相似文献
7.
S. Leela K. Ramamurthi G. Bhagavannarayana 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2009,74(1):78-83
An organic nonlinear optical material, 4-chloro-4′dimethylamino-benzylidene aniline (CDMABA), was synthesized by the condensation of the p-chloroaniline and p-dimethylaminobenzaldehyde. Solubility of CDMABA was determined in acetone at different temperatures. Single crystals were grown by the solvent evaporation method from acetone solution at room temperature. Grown crystal was subjected to FTIR, FT-Raman and 1H NMR spectral analyses to confirm the synthesized compound. The range and percentage of optical transmission was ascertained by recording UV–vis–NIR spectrum. Thermal properties were investigated by Thermo Gravimetric, Differential Thermal and Differential Scanning Calorimetric analyses. High Resolution X-ray Diffractometry (HRXRD) was employed to evaluate the perfection of the grown crystal. The third order nonlinear optical parameters (nonlinear refractive index and nonlinear absorption coefficient) were derived by the Z-scan technique. 相似文献
8.
New inorganic type II clathrates with Ag atoms substituting for framework Ge atoms, Cs8Na16AgxGe136−x (x=0, 5.9, and 6.7), have been synthesized by reaction of the pure elements at high temperature. Structural refinements have been performed using single crystal X-ray diffraction. The materials crystallize with the cubic type II clathrate crystal structure (space group ) with a=15.49262(9) Å, 15.51605(6) Å, and 15.51618(9) for x=0, 5.9, and 6.7, respectively, and Z=1. The structure is formed by a covalently bonded Ag-Ge framework, in which the Cs and Na atoms are found inside two types of polyhedral cages. Ag substitutes for Ge in the tetrahedrally bonded framework positions, and was found to preferentially occupy the most asymmetric 96g site. The proven ability to substitute atoms for the germanium framework should offer a route to the synthesis of new compositions of type II clathrates, materials that are of interest for potential thermoelectrics applications. 相似文献
9.
Single crystals of a new organic material, 4-hydroxy-l-proline-l-tartaric acid (HPTA) adduct, were grown by slow evaporation of an aqueous solution containing equimolar concentrations of 4-hydroxy-l-proline and l-tartaric acid at room temperature. Formation of new crystal has been confirmed by single crystal X-ray diffraction and NMR spectroscopic techniques. The single crystal XRD analysis shows that a molecule of 4-hydroxy-l-proline and a molecule of free l-tartaric acid both of which are interlinked to each other by two types of H-bonding interactions, namely O(6)–H(6)⋯O(2) and N(1)–H(1B)⋯O(10). The title compound (HPTA) crystallizes in monoclinic crystal system with non-centrosymmetric space group P21. The suitability of the crystal for optical applications was studied by UV–Vis–NIR spectroscopy. Fourier transform infrared (FT-IR) spectral analysis was used to confirm the presence of various functional groups in the grown crystals. The thermal stability of the compound was investigated by thermogravimetric and differential thermal analyses. The dielectric constant and dielectric loss of the crystal were studied as a function of frequency and temperature. The fluorescence spectral analysis of the title crystal shows an indigo emission. The second order nonlinear optical (NLO) property of the crystal was confirmed by the modified Kurtz–Perry powder second harmonic generation (SHG) test. 相似文献
10.
Two novel 3D coordination polymers {[Mn(aip)(DMF)]}n, CPO-9, and {[Mn3(Hatp)2(atp)2](H2O)2(DEF)4}n CPO-10 (aip = 5-aminoisophthalate, atp = 2-aminoterephthalate, DMF = dimethylformamide, DEF = diethylformamide) have been synthesized by solvothermal methods. Their properties have been studied by single-crystal X-ray diffraction, thermogravimetric analysis, high-temperature powder X-ray diffraction and magnetic susceptibility measurements. The crystal structure of CPO-9 is based on infinite chains of carboxylato-bridged five-coordinated Mn(II) ions that are crosslinked via the aip ligands to form a 3D structure. CPO-10 is based on linear trinuclear building units of carboxylato-bridged octahedral Mn(II) ions that are crosslinked by the atp ligands into a 3D structure. Both compounds have 1D channels that contain solvent molecules. The solvent accessible void volume for CPO-10 is 51.9% of the unit cell volume. For both compounds, however, the solvent molecules cannot be removed without the collapse of the structures into amorphous phases at 250 °C. The magnetic susceptibility measurements indicate antiferromagnetic couplings between the Mn(II) ions in both compounds. The magnetic data have been fitted using theoretical approaches. 相似文献
11.
The crystal structures of new quaternary compounds La3AgSnSe7 (space group P63, Pearson symbol hP24, a=1.0805(4) nm, c=0.6245(1) nm, R1=0.0315), La3Ag0.82SnS7 (space group P63, Pearson symbol hP23.64, a=1.0399(1) nm, c=0.6016(1) nm, R1=0.0149) and Ce3Ag0.81SnS7 (space group P63, Pearson symbol hP23.62, a=1.0300(1) nm, c=0.6002(1) nm, R1=0.0151) were determined by means of X-ray single crystal diffraction. Structural investigations of the R3Ag1−δSnS7 (R=La, Ce; δ=0.18-0.19(1)) compounds at 450 and 530 K were performed. Low temperature data (12 K) for Ce3Ag0.81SnS7 were also collected. The nearest neighbours of the La(Ce), Ag and Sn atoms are exclusively Se(S) atoms. The latter form distorted trigonal prisms around the La(Ce) atoms, and distorted tetrahedrons around the Sn atoms. The Ag (Ag1) atoms have triangular surroundings: they are located very close to the planes built of three Se(S) atoms. The Ag2 atoms in the structures of the La3Ag0.82SnS7, Ce3Ag0.81SnS7 compounds are located practically in the centres of trigonal antiprisms. The pseudo-potentials determined through the Ag atoms show relatively low barrier between two nearest positions which decreases when temperature rises. 相似文献
12.
Anke Flemming 《Journal of solid state chemistry》2008,181(10):2660-2665
Slow crystallization of (PyrH)2[Nb6Cl18] from hot ethanol solution affords triclinic (PyrH)2[Nb6Cl18]·EtOH. Treatment of [Nb6Cl14(H2O)4]·4H2O with pyridine in a methanol solution gives the second title compound, the cubic modification of (PyrH)2[Nb6Cl18]. Both structures were determined by single crystal X-ray diffraction, (PyrH)2[Nb6Cl18]·EtOH: P1¯, a=9.3475(3), b=9.3957(3), c=10.8600(3) Å, α=82.582(1)°, β=78.608(1)°, and γ=78.085(1)°, Z=1, R1(F)/wR2(F2)=0.0254/0.0573, cub.-(PyrH)2[Nb6Cl18]: Fd3¯m, a=19.935(2) Å, Z=8, R1(F)/wR2(F2)=0.0557/0.1796. The cluster compounds contain isolated, molecular [Nb6Cli12Cla6]2− cluster anions with an octahedron of metal atoms edge bridged by chlorido ligands with additional ones on all the six exo positions. These cluster anions are separated by the pyridinium cations and ethanol solvent molecules, respectively. For the cubic modification of (PyrH)2[Nb6Cl18], a structural comparison is given to the known rhombohedral modification using the group-subgroup relations as expressed by a Bärnighausen tree. 相似文献
13.
Band structure calculations at the level of LMTO-ASA provide insight into the electronic structure of BaV10O15 and the origin of the structural phase transition. A crystal orbital Hamiltonian population/integrated crystal orbital Hamiltonian population analysis provides evidence that the crystallographic phase transition is driven by V-V bond formation. As well, the energy bands near the Fermi level are very narrow, <1 eV, consistent with the fact that the observed insulating behavior can be due to electron localization via either Mott-Hubbard correlation and/or Anderson disorder. The partial solid solution, BaV10−xTixO15, was examined to study the effect of Ti-doping at the V sites on the structure and electronic transport properties. In spite of the non-existence of “BaTi10O15”, the limiting x=8, as indicated by a monotonic increase in the cell volume and systematic changes in properties. This limit may be due to the difficulty of stabilizing Ti2+ in this structure. For x=0.5 both the first order structural phase transition and the magnetic transition at 40 K are quenched. The samples obey the Curie-Weiss law to x=3 with nearly spin only effective moments along with θ values which range from −1090 K (x=0.5) to −1629 K (x=3). For x>3 a very large, ∼2×10−3 emu/mol, temperature independent (TIP) contribution dominates. Conductivity measurements on sintered, polycrystalline samples show semiconducting behavior for all compositions. Activation energies for Mott hopping derived from high temperature data range from ∼0.1 eV for x=0-1 and fall to a plateau of 0.06 eV for x=3-7. Low temperature data for x=3, 5 and 7 show evidence for Mott variable range hoping (VRH) with a T1/4 law and in one case between 5 and 17 K, a Efros-Shklovskii correlated hopping, T1/2 law, was seen, in sharp contrast to BaV10O15 where only the E-S law was observed up to 75 K. Seebeck coefficients are small (<35 μV/K), positive, roughly TIP and increase with increasing x up to x=5. This may point to a Heikes hopping of holes but a simple single carrier model is impossible. The compositions for x>3 are remarkable in that local moment behavior is lost, yet a metallic state is not reached. The failure of this system to be driven metallic even at such high doping levels is not fully understood but it seems clear that disorder induced carrier localization plays a major role. 相似文献
14.
Graham King Lora M. Wayman Patrick M. Woodward 《Journal of solid state chemistry》2009,182(6):1319-2406
We have prepared 14 new AA′BB′O6 perovskites which possess a rock salt ordering of the B-site cations and a layered ordering of the A-site cations. The compositions obtained are NaLnMnWO6 (Ln=Ce, Pr, Sm, Gd, Dy, and Ho) and NaLnMgWO6 (Ln=Ce, Pr, Sm, Eu, Gd, Tb, Dy, and Ho). The samples were structurally characterized by powder X-ray diffraction which has revealed metrically tetragonal lattice parameters for compositions with Ln=Ce, Pr and monoclinic symmetry for compositions with smaller lanthanides. Magnetic susceptibility vs. temperature measurements have found that all six NaLnMnWO6 compounds undergo antiferromagnetic ordering at temperatures between 10 and 13 K. Several compounds show signs of a second magnetic phase transition. One sample, NaPrMnWO6, appears to pass through at least three magnetic phase transitions within a narrow temperature range. All eight NaLnMgWO6 compounds remain paramagnetic down to 2 K revealing that the ordering of the Ln3+ cations in the NaLnMnWO6 compounds is induced by the ordering of the Mn2+ sub-lattice. 相似文献
15.
The diol host compound 2 has been synthesised and its behaviour to form crystalline inclusion compounds is discussed in comparison with an analogous ethynylene spaced host compound 1. The rotation around the fluorenol–anthracene bonds in 2 is highly restricted as indicated by solution NMR spectroscopy, molecular mechanics and semi-empirical calculations. Single-crystal X-ray structures of the inclusion complexes of 2 with 1-BuOH (2a), morpholine/H2O (2b) and DMSO (2c) are in agreement with the bent geometry of the anthracene ring system suggested by the calculations. The structures exhibit specific modes of hydrogen bond interactions. 相似文献
16.
Aitor Larrañaga José L. Pizarro Roger Olazcuaga Teófilo Rojo 《Journal of solid state chemistry》2005,178(12):3686-3697
Two new manganese(II) selenite polymorphs with formula Mn(SeO3)·H2O have been synthesized by slow evaporation from an aqueous solution. The crystal structure of both compounds (1) and (2) have been solved from X-ray diffraction data. The structure of (1) was determined from single-crystal X-ray diffraction techniques. The compound crystallizes in the Ama2 space group, with a=5.817(1), b=13.449(3), and Z=4. The structure of (2) has been solved from X-ray powder diffraction data. This phase crystallizes in the P21/n space group with unit-cell parameters of a=4.921(3), b=13.121(7), , β=90.03(2)° and Z=4. Both polymorphs exhibit a layered structure formed by isolated sheets of MnO6 octahedra and (SeO3)2− trigonal pyramids in the (010) plane. These layers, which contain one manganese and selenium atom crystallographically independent, are formed by octahedra linked between them through the selenite oxoanions. The difference of both compounds consists in the stacking of the layers along the b-axis. The IR spectra show the characteristic bands of the selenite anion. Studies of luminescence performed at 6 K and diffuse reflectance spectroscopy have been carried out for both phases. The Dq and Racah (B and C) parameters, from luminescence and diffuse reflectance spectroscopy, are Dq=705, B=750, for (1) and Dq=720, B=745, for (2). The ESR spectra of both compounds are isotropic with g-values of 1.99(1). Magnetic measurements indicate the presence of antiferromagnetic couplings in both phases. The J-exchange parameters have been estimated by fitting the experimental magnetic data to a model for square-planar lattice. The values obtained are J/k=-0.83, −0.91 K and J′/k=-0.97, −1.20 K, for polymorphs (1) and (2), respectively. 相似文献
17.
《Mendeleev Communications》2022,32(5):664-666
2,3-Bis- and 2,3,5,6-tetrakis(diphenylphosphoryl)-substituted pyrazines have been synthesized from the corresponding polychloropyrazines and ethyl diphenylphosphinite. They may serve as new N,O-bidentate organophosphorus ligands for extraction and recovery of f-block metal ions from nitric acid solutions. 相似文献
18.
《Acta Crystallographica. Section C, Structural Chemistry》2017,73(12):1071-1077
Two new isostructural compounds, namely heptapotassium silver tetrakis(tetraoxomolybdate), K7–x Ag1+x (MoO4)4 (0 ≤ x ≤ 0.4), and heptapotassium silver tetrakis(tetraoxotungstate), K7–x Ag1+x (WO4)4 (0 ≤ x ≤ 0.4), have been synthesized and found to crystallize in the polar space group P 63mc (Z = 2) with the unit‐cell dimensions a = 12.4188 (2) and c = 7.4338 (2) Å for K6.68Ag1.32(MoO4)4 (single‐crystal data), and a = 12.4912 (5) and c = 7.4526 (3) Å for K7Ag(WO4)4 (Rietveld analysis data). Both structures represent a new structure type, with characteristic [K1(X O4)6] `pinwheels' of K1O6 octahedra and six X O4 tetrahedra (X = Mo, W) connected by common opposite faces into columns along the c axes. The octahedral columns are linked to each other through Ag1O4 tetrahedra along with the K2 and K3/Ag2 polyhedra, forming the polar rods (…Ag1O4–X 1O4–empty octahedron–Ag1O4…). Ag1 is located almost at the centre of the largest face of its coordination tetrahedron and seems to have some mobility. The new structure type is related to the Ba6Nd2Al4O15 and CaBaSiO4 types, and to other structures of the α‐K2SO4–glaserite family. The differential scanning calorimetry (DSC) and second harmonic generation (SHG) results show that both compounds undergo first‐order phase transformations to high‐temperature centrosymmetric phases. 相似文献
19.
Alexander Gribanov Andriy Grytsiv Yurii Seropegin 《Journal of solid state chemistry》2010,183(6):1278-1289
Two series of intermetallic alloys, RT2Si and RTSi2, have been synthesized from stoichiometric compositions. The crystal structures of EuPt1+xSi2−x (CeNiSi2-type), CeIr2Si (new structure type), YbPd2Si and YbPt2Si (both YPd2Si-type) have been elucidated from X-ray single crystal CCD data, which were confirmed by XPD experiments. The crystal structures of LaRh2Si and LaIr2Si (CeIr2Si-type), {La,Ce,Pr,Nd}AgSi2 (all TbFeSi2-type), and EuPt2Si (inverse CeNiSi2-type) were characterized by XPD data. RT2Si/RTSi2 compounds were neither detected in as-cast alloys Sc25Pt50Si25, Eu25Os25Si50 and Eu25Rh25Si50 nor after annealing at 900 °C. Instead, X-ray single crystal data prompted Eu2Os3Si5 (Sc2Fe3Si5-type) and EuRh2+xSi2−x (x=0.04, ThCr2Si2-type) as well as a new structure type for Sc2Pt3Si2 (own type). 相似文献
20.
《Arabian Journal of Chemistry》2020,13(1):649-670
In recent years, metals based antitumor complexes have played a vital role in chemotherapy. Therefore, in this study, some new imine Cr(III), VO(II) and Ni(II) complexes incorporating ESAP imine ligand (2-Ethoxy-6-((2-hydroxy-phenylimino)-methyl)-phenol were designed and synthesized. The investigated complexes were fully characterized by micro analysis, infrared, electronic spectra, thermal analysis (TGA), conductivity as well as magnetic susceptibility measurements. Moreover, the stability constants of the prepared complexes were determined spectrophotometrically. The results suggest that the titled ESAP imine ligand serves as tri-dentate moiety through deprotonated two phenolic oxygen and azomethene nitrogen atoms for coordination to Cr(III) in octahedral geometry, tetrahedral to Ni(II) and distorted square pyramidal to VO(II). The electronic structure and nonlinear optical parameters NLO of the newly synthesized complexes are investigated theoretically at the B3LYP/GEN level of theory. The studied complexes show promising optical properties. Indeed, the prepared compounds were evaluated for antimicrobial effect against some types of bacteria and fungi. The investigated complexes exhibit a stronger antimicrobial efficiency compared to its ligand. Moreover, the interaction of the complexes with CT-DNA was monitored using spectral studies, viscosity and gel electrophoreses measurements. Furthermore, the cytotoxic activity of the prepared imine complexes on human colon carcinoma cells, hepatic cellular carcinoma cells and breast carcinoma cells have shown promising results and enhancement of the anti-proliferative activity compared to its ligand. The molecular docking into TRK (PDB: 1t46) was done for the optimization of the investigated compounds as potential TRK inhibitors. 相似文献