共查询到20条相似文献,搜索用时 18 毫秒
1.
Karim Dahmouche Mohamed Atik Nilson C. Mello Tito J. Bonagamba Horacio Panepucci Michel A. Aegerter Patrick Judeinstein 《Journal of Sol-Gel Science and Technology》1997,8(1-3):711-715
Two families of hybrid organic-inorganic composites exhibiting Li+ ionic conduction (ORMOLYTES) have been prepared by the sol-gel process. The first family, prepared from a mixture of 3-isocyanatopropyltriethoxysilane, O,O Bis (2-aminopropyl)-polyethyleneglycol (or O,O Bis (2-aminopropyl)-polypropyleneglycol) and lithium salt, presents chemical bonds between the organic and the inorganic phase and an ionic conductivity higher than 10-4 S m-1 at room temperature. Their properties have been related to their structure using liquid state NMR measurements of 7Li between -100°C and +100°C and the DMTA technique. In the second family, prepared by ultrasonic method from a mixture of tetraethoxysilane (TEOS), polyethyleneglycol (PEG) and lithium salt, the organic and inorganic phases are not chemically bonded. Ionic conductivity has been studied as a function of the polymer chain length and concentration. Values of up to 10-2 S m-1 at room temperature have been obtained (with a silica-PEG300 system, PEG/TEOS = 40% in weight). Again, structure was investigated by liquid state 7Li NMR measurements. 相似文献
2.
Korolev D. A. Chezhina N. V. Glumov O. V. 《Russian Journal of General Chemistry》2019,89(6):1129-1135
Russian Journal of General Chemistry - The coexistence of two crystal modifications of lanthanum gallate, orthorhombic and rhombohedral, was revealed for the first time in two series of solutions:... 相似文献
3.
The reaction of lanthanum(Ⅲ) nitrate and 5-nitroisophthalic acid in isopropanol/H2O under hydrothermal conditions leads to a 3D lanthanum-containing coordination polymer with the general chemical formula {[La6(Nip)9(H2O)4 ]·(H2O)4 }∞(1,Nip=5-nitroisophthalate).The single-crystal X-ray analyses show that this compound crystallizes in the orthorhombic system,space group Ima2 with a=9.7769(12),b=28.239(3),c=21.149(2),V=5839.1(11)3,Z=2,Mr=2859.61,Dc =1.626 g/cm 3,F(000)=2752.14040 reflections are collected,of which 5275 are unique (R int=0.0241).Final GOOF=1.083,R=0.0406 and wR=0.1182,R indices based on 5183 reflections with I>2σ(I)(refinement on F2),443 parameters,1 restraint.Lp and absorption corrections were applied,=2.242mm-1.Absolute structure parameter x=0.08(3).The crystal structure can be described as the butterfly-liked hexanuclear lanthanum entities {La6O6(CO2)8 } covalently linked to each other by nitroisophthalate ligands into an intricate three-dimensional structure.The fluorescence spectroscopy of compound 1 has been investigated. 相似文献
4.
The new tetragonal phases La(3)In(4)Ge and La(3)InGe are obtained from high-temperature reactions of the elements in welded Ta followed by annealing. The structures of both were established by single-crystal X-ray diffraction in tetragonal space group I4/mcm (Z = 4 and 16, a = 8.5165(3) and 12.3083(2) ?, c = 11.9024(4) and 16.0776(4) ?, respectively). La(3)In(4)Ge contains layers or slabs of three-connected indium built of puckered 8-rings and 4-rings, or of squashed tetrahedra ("butterflies") interlinked at all vertices, and these are separated by layers of La and isolated Ge. The phase is deficient of being a Zintl phase by three electrons per formula unit and is better described in terms of an alternate optimized and delocalized bonding picture and an open-shell metallic behavior for the In slabs. The more complex La(3)InGe, isostructural with Gd(3)Ga(2), is also layered. This phase contains pairs of mixed-occupancy (0.75 In, 0.25 Ge) sites separated by 3.020 ?, as well as isolated In and Ge atoms. The former appear to be fully reduced closed-shell atoms (relative to the bonded Ga dimers in Gd(3)Ga(2)) that are held in somewhat close proximity by cation matrix effects. The compound appears to be semiconducting and thus is a classical Zintl phase, (La(+3))(3)In(-5)Ge(-4) in the simplest oxidation state notation. High Coulomb energies are presumably important for the nature of the bonding and the stabilities of both compounds. 相似文献
5.
采用溶胶-凝胶法制备了CaTiO3:Zn纳米粒子,透射电镜图显示平均粒径为25 nm.Zn的掺杂位置对于陶瓷相组成和烧结特性有很大影响.Ca1-xZnxTiO3和CaTiO3+zZnO样品的Zn以Zn2TiO4相形式存在;而CaZnyTi1-yO3-δy=0.01)样品中的Zn进入Ti位形成固溶体,无明显的降温效果,当Zn量增至0.05和0.1时,出现ZnO相.ZnO和Zn2TiO4第二相的存在均能明显促进陶瓷烧结.CaTiO3:Zn超细粉体可在较低温度下致密烧结(≤1 250 ℃).1 250℃烧结的CaZnyTi1-yO3-δ(y=0.01)陶瓷具有较好的介电性能:介电常数ε=157,品质因数Q×f=6 819 GHz,谐振频率温度系数(τ)f=7.51×10-4℃-1. 相似文献
6.
HE Qiang HE Tian-min PEI Li JI Yuan 《高等学校化学研究》2006,22(5):643-646
IntroductionIn intermediate-temperature solid oxide fuel cells(SOFCs),doped ceria with a fluorite structure anddoped lanthanum gallate(LSGM)with a perovskitestructure are commonly used as electrolyte materials.However,the former easily exhibits an electro… 相似文献
7.
2-fluorobenzoic acid (2-HFBA) and 2,2′-bipyridine (2,2′-bpy) was used as ligands to react with lanthanum to obtain a complex, [La(2-FBA)3·(2,2′-bpy)]2. The structure of the complex contains three independent molecules. In two of them, the two central metal ions are connected together through four 2-FBA groups by bidentate bridging and chelating-bridging two modes. In another, the two central metal ions are connected together through four bidentate bridging 2-FBA groups. CCDC: 237658. 相似文献
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10.
Shashkova I. L. Rat'ko A. I. Koshevar V. D. Kitikova N. V. D'yachenko A. G. 《Russian Journal of Applied Chemistry》2002,75(3):339-344
A possibility of modifying natural carbonate fillers for paint and varnish industry by solutions of salts of some nonferrous metals was studied. Reactions of carbonates with metal ions and physicotechnical properties of the resulting materials were considered. 相似文献
11.
Berezhnaya M. V. Perov N. S. Almjasheva O. V. Mittova V. O. Nguyen A. T. Mittova I. Ya. Druzhinina L. V. Alekhina Yu. A. 《Russian Journal of General Chemistry》2019,89(3):480-485
Russian Journal of General Chemistry - Barium-doped nanocrystalline lanthanum ferrite was synthesized by the method of co-precipitation and subsequent annealing at 1000°C. The maximum degree... 相似文献
12.
Fang-Dong Zhuang Jing-Hui Yang Ze-Hao Sun Peng-Fei Zhang Qi-Ran Chen Jie-Yu Wang Jian Pei 《中国化学》2021,(4):909-912
By combination of two special structural units,a boron-nitrogen-fused polycyclic aromatic hydrocarbon and azulene with strong in-tramolecular dipoles,a novel BN... 相似文献
13.
磷烯是继石墨烯之后一种新型的二维材料,具有优异的物理、化学和机械性能,在各类器件中具有大的应用潜力。目前对磷烯的最新制备方法、特性调控和应用的系统总结较少。本文对磷烯的制备、结构、性质、改性方法及其器件应用进行了系统的综述。首先概括了磷烯"自上而下"和"自下而上"的制备方法,对其结构和性质进行了总结,同时讨论了磷烯的修饰改性方法,最后对磷烯的器件应用进行了较详细的介绍,并在此基础上对磷烯的研究方向和前景进行了展望。 相似文献
14.
G. M. Kuzmicheva V. N. Kokunova A. V. Mitin I. E. Kostyleva E. P. Khlybov A. S. Andreenko 《Journal of Structural Chemistry》2004,45(2):231-252
This paper reports on synthesis and X-ray diffraction study of two groups of phases obtained from batch mixtures: (La,Sr
k+1(Ru,Cu)
k
O3k+1 and (La,Sr)3(Ru,Cu)3O6+ (group I); RuSr2LnCu2O8– (Ln = Nd for the first time, Sm, Eu, Gd, (Gd,Y) for the first time), RuSr2(Ln,Ce4+)2Cu2O10– (Ln = Pr and Nd for the first time, Sm, Eu, Gd, (Gd,Y) for the first time), and (Ru,Cu)Sr2(Ln,Ce4+)2Cu2O10– (Ln = Tb and Y for the first time) (group II). In group I, phases with K2NiF4, Sr3Ti2O7, and cubic perovskite type structures are typically formed; in group II, these are respectively (Ru,Cu)(Sr,Ln)2(Ln,Sr)Cu2O8– (1212 type), (Ru,Cu)(Sr,Ln)2(Ln,Ce4+)2Cu2O10– (1222 type), and cubic perovskite type structures (the content of the latter depends on the type of Ln). Variation of the formal charge (f.c.) of Ru (group I) and Cu (group II) was evaluated in relation to the cation composition of the phases (groups I and II) and the content of superstoichiometric oxygen (group II). Phases of 1222 type with Ln = Nd, Sm, Eu, Gd, and (Gd,Y) and phases of 1212 type with Ln = Gd exhibited superconducting properties with T
c max 40 K. 相似文献
15.
Kravchenko S. E. Burlakova A. G. Domashnev I. A. Vinokurov A. A. Shilkin S. P. 《Russian Journal of General Chemistry》2019,89(4):641-646
Russian Journal of General Chemistry - X-ray diffraction, scanning electron microscopic, and X-ray photoelectron spectroscopic examinations, as well as energy dispersive X-ray and elemental... 相似文献
16.
Yi Peng Prof. Dr. Shuo Tong Dr. Yang Zhang Prof. Dr. Mei-Xiang Wang 《Angewandte Chemie (International ed. in English)》2023,62(24):e202302646
Hydrocarbon belts have drawn great attention because of their unique structures and tantalizing properties. Although a few belts and heteroatom-doped analogs have been synthesized, belt molecules containing non-hexagonal rings remain rare. Herein we report the construction and application of unprecedented zigzag-type hydrocarbon belts which contain functionalized eight-membered rings. The synthesis features fourfold intramolecular acylation reactions of resorcin[4]arene-derived intermediates, which affords C4-symmetric tetrabenzobelt[4]arene[4]cyclooctatrienones. Stereoselective ketone reduction with LiAlH4 and nucleophilic addition with alkynyllithiums provide the corresponding tetrahydroxylated belts. The tetraol and its methyl ether are powerful and selective hosts to form 2 : 1 and 1 : 1 complexes with cesium ion, respectively, with binding constants up to (1.71±0.33)×1011 M−2 and (1.50±0.16)×106 M−1. In addition, enantiopure C4-symmetric belts can emit CPL with |glum| being around 0.01. 相似文献
17.
以2,6-二甲基吡啶-3,5-二羧酸(H2L1)为主配体,1,10-菲咯啉(L2)为辅配体,分别与五水合硝酸镝、六水合硝酸铽及六水合硝酸铕通过水热法合成[Dy2(L1)3(L2)2]n(1)、{[Tb2(L1)3(L2)2]·5H2O}n(2)和{[Eu2(L1)3(L2)2]·5H2O}n(3)三种配合物。通过单晶X射线衍射、红外光谱、荧光光谱和热重分析对其结构进行了表征与性质研究。结果表明,配合物1~3均以稀土离子为金属节点连接配体L12-和L2,形成无限延伸的一维链状结构。 相似文献
18.
《结构化学》2019,38(6)
Two new Zn(Ⅱ) and Cd(Ⅱ) coordination complexes, [Zn(ppda)(idz)]_n(1) and [Cd(mpda)(mbib)]_n(2)(H2 ppda = 1,4-phenylenediacetic acid, H_2 mpda = 1,3-phenylenediacetic acid, idz = imidazole, mbib = 1,3-bis(imidazol-1-ylmethyl)benzene), have been synthesized by using Zn(Ⅱ)/Cd(Ⅱ) salt and phenylenediacetic acid in the presence of different imidazole ligands under hydrothermal conditions, and characterized by elemental analysis, IR spectroscopy, single-crystal X-ray crystallography and thermogravimetric analysis. Complex 1 crystallizes in orthorhombic system, Iba2 space group. The carboxylic acid ligands form a 2 D helical layer with Zn(Ⅱ) ions, and such layers are expanded into a 3 D network structure by the force of C–H×××π. Complex 2 crystallizes in monoclinic system, P2_1/n space group. Complex 2 shows a 3 D framework with two Cd(Ⅱ) ions as nodes of a dual-core unit, which can be considered to be 6-connected net and regarded as a rare(4~4,5~(10),7) topology network with self-interlacing. The structural diversities indicate that rigid and flexible imidazole ligands play dominating roles in modulating the formation of structures of these crystalline materials. Moreover, the luminescent properties of two complexes are investigated in solid state. 相似文献
19.
H.K. Schmidt 《Journal of Sol-Gel Science and Technology》1997,8(1-3):557-565
Based on the concept of controlling the particle size by the surface free energy, the growth of sol-gel derived nanoparticles
(Al2O3, TiO2, ZrO2) has been investigated in presence of molecules with binding ability to the growing particles. The investigations show that
the use of silanes, carboxylic acid or β-diketones allows to replace electrostatic sol stabilisation by steric sol stabilisation
and through this, high solid content sols can be obtained. The introduction of these sols into orgaic or ormocer type of matrices
leads to nano composites with degrees of filling up to 40 wt.-% without agglomeration and with high optical quality. Already
developed TiO2 containing bulk materials, ultrahard coatings on plastic and adhesives for fiber to chip coupling are examples for the usefulness
of this alternative sol-gel route. The nanocomposite materials show interesting mechanical and thermomechanical properties
such as high hardness or low thermal expansion compared to unfilled systems. 相似文献
20.
A novel compound, (IBzQI)(TCNQ)2 2 (IBzQ1=1-(4-iodobenzyl)quinolinium and TCNQ = 7,7,8,8-tetracyanoquinodimethane) has been fabricated and X-ray single-crystal structurally analyzed. This compound crystallizes in the triclinic system, space group P1 with a = 8.3540(17), b = 13.284(3), c = 16.185(3) А, α= 82.12(3), β= 75.19(3), γ= 72.34°, V = 1651.2(6) А^3, Z= 2, C_40H_21IN_9, Mr = 754.56, Dc = 1.518 g/cm^3,μ= 1.015 mm^-1, S = 1.010, F(000) = 754, R = 0.0387 and wR = 0.0948. The structure analysis shows that the anions are stacked into column with tetrads, and there are two types of TCNQ entries (TCNQ-1 and TCNQ^0) in agreement with the IR spectra analysis of the compound. The temperature dependence of the magnetic susceptibility (2-300 K) for 2 exhibits spin gap of singlet-triplet feature, and the best fit gave △/kB = 1523.4 K. In order to understand both magnetic behavior and local charge distribution of [(TCNQ)2]-unit, the molecular orbital calculations and analysis based on extended Hückel method were performed, and the results support the analyses of both crystal structure and IR spectra. 相似文献