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1.
It is becoming a focus to synthesize and assemble organic-inorganic materials, especially, to synthesize charge-transfer complexes formed by polyoxometalate and organic donors. They have attracted much attention because such complexes are active in their electric, magnetic and optic properties1-4, many investigations about them have been done and some crystal structures of them were reported5-6. But, the disadvantage of these crystals is instability at room temperature. According to the view…  相似文献   

2.
以溴化1-丁基-3-甲基咪唑盐([bmim]Br)和磷钨酸(H3PW12O40)为原料制备了1-丁基-3-甲基咪唑磷钨酸盐([bmim]3PW12O40)催化剂,并用傅里叶变换红外光谱、热重分析-差示扫描量热法、正丁胺电位滴定及元素分析等技术对催化剂进行了表征,考察了催化剂对乙醇与乙酸酯化合成乙酸乙酯反应的催化活性.结果表明,[bmim]3PW12O40中有3个结晶水,并保持有H3PW12O40的Keggin结构和酸强度,[bmim]3PW12O40的酸量明显少于H3PW12O40的酸量.在乙醇与乙酸酯化合成乙酸乙酯反应中,[bmim]3PW12O40催化剂具有较高的催化活性和较好的重复使用性能.  相似文献   

3.
The synthesis of hexanuclear lanthanide hydroxo complexes by controlled hydrolysis led to polymorphic compounds. The hexanuclear entities crystallize in four different ways that depend on the extent of their hydration. The four structures can be described as hexanuclear lanthanide entities with formula [Ln(6)(mu(6)-O)(mu(3)-OH)(8)(NO(3))(6)(H(2)O)(12)](2+). Two additional NO(3)(-) ions intercalate between the hexanuclear entities in order to ensure the electroneutrality of the crystal structure. Some crystallization water molecules fill the intermolecular space. The three first families of compounds (1-3) exhibit crystal structures that have previously been reported. The fourth family of compounds (4) is described here for the first time. Its chemical formula is [Ln(6)(mu(6)-O)(mu(3)-OH)(8)(NO(3))(6)(H(2)O)(12)](NO(3))(2).2H(2)O (Ln = Gd, Er, and Y). In this paper, the chemical and thermal stabilities of the hexanuclear lanthanide compounds are reported together with the magnetic properties of the Gd(III)-containing species. To use these entities as precursors for new materials, the substitution of the nitrato groups by chloride ions has been studied. Two byproduct compounds have so been obtained: The first (compound 5) is a nitrato/chloride hexanuclear compound of chemical formula [Er(6)(mu(6)-O)(mu(3)-OH)(8)(NO(3))(6)(H(2)O)(12)](NO(3))Cl.2H(2)O. The second one (compound 6) is a polymeric compound in which the hexanuclear entities are linked by an unexpected and original N(2)O(4) bridge. Its chemical formula is [Er(6)(mu(6)-O)(mu(3)-OH)(8)(NO(3))(4)(H(2)O)(11)(OH)(ONONO(2))]Cl(3).2H(2)O. Its crystal structure can be described as the juxtaposition of chainlike molecular motifs. To the best of our knowledge, this is the first example of a coordination polymer synthesized from an isolated polylanthanide hydroxo complex.  相似文献   

4.
1 INTRODUCTION A great deal of interest in transition metal com- plex assembly has recently been devoted to the development of rational synthetic routes to novel one-, two- and three-dimensional crystal frameworks, due to their potential applications in…  相似文献   

5.
用MnSO4·H2O,KSCN,六次甲基四胺(HMTA)制备出超分子化合物[Mn(NCS)2(H2O)2(HMTA)2][Mn(NCS)2(H2O)4](H2O)2,并测定了其晶体结构。该化合物由[Mn(NCS)2(H2O)2(HMTA)2],[Mn(NCS)2(H2O)4]和H2O三部分组成,每一个HMTA配体中仅有一个N原子与Mn原子配位,剩余的3个N分别与[Mn(NCS)2(H2O)4]中的H2O及结晶H2O之间形成氢键。[Mn(NCS)2(H2O)2(HMTA)2]和[Mn(NCS)2(H2O)4]之间通过N…H—O氢键边接成无限延伸的线性长链,链与链、以及链和结晶H2O之间通过七种形式的氢键构成三维结构的超分子。用Z-扫描法测定该化合物在DMF溶液中的三阶非线性光学性质,发现它具有自聚焦效应,三阶非线性折射系数n2=9.52×10^-9m^2·W^-1,非线性极化率χ^(3)=3.41×10^-12esu.  相似文献   

6.
The single crystal of [Ba(H2O)2(C6H12O6)2Cl2] was obtained based on the phase equilibrium results. Its structure was determined by X-ray crystallographic analysis. The crystals are monoclinic and in space group C2/c with a=1.901 7(2) nm, b = 0.682 13(8) nm, c = 0.162 60(2) nm,β=96.593(2)°and V= 2.095 3(4) nm3, Z= 4, DC=1.917 g·cm-3. In its solid state, this supramolecular complex is a three-dimensional network with double layers connected by hydrogen bondings. The molecule structure of [Ba(H2O)2(C6H12O6)2Cl2] has a central barium ion that is coordinated to two water molecules, two chlorides, and four hydroxyls from the two inosi-tols. Losing the coordinating water is controlled by random nucleation and growth mechanism (n = 2/3) and 3-dimensional diffusion mechanism (n=2).  相似文献   

7.
The title complex, [CaCu(C3H2O4)2(H2O)4]n, with a formula of C6H12CaCuO12 and Mr=379.78 has been sy-nthesized and characterized by single crystal X-ray diffraction structure analysis, elemental analysis, IR spectra and TG-DTG techniques. The results show that the crystal is Orthorhombic, space group Pbcn with a=0.669 21(5) nm, b=1.370 23(5) nm, c=1.322 39(10) nm, V=1.212 59(16) nm3, Dc=2.080 g·cm-3, μ=2.288 mm-1, F(000)=772 and Z=4. The final R=0.054 0 and wR=0.112 8 for 1 189 observed reflections with I>2σ(I). The structure of the title complex consists of CaO8 polyhedra and CuO6 elongated octahedra linked together by malonate ligands. The Ca(Ⅱ) cation, on a twofold axis, is coordinated by two water molecules and six malonate O atoms. The Cu(Ⅱ) cation, which lies in a centre of symmetry in an octahedral arrangement, is coordinated by four malonate O atoms and two water molecules. The structure comprises alternating layers along the [101] plane, with the shortest Cu…Cu distance of 0.762 46(6) nm. The whole 3D structure is maintained and stabilized by the presence of hydrogen bonds. Its thermo gravimetric analysis was determined by TG-DTG techniques. CCDC:663184.  相似文献   

8.
铌取代型杂多钨酸盐的合成、表征、生物活性及晶体结构   总被引:3,自引:0,他引:3  
合成了铌、过氧化铌取代的钨硅、钨锗杂多配合物M  相似文献   

9.
白小红  魏雁声 《分析化学》1997,25(7):822-824
利用高灵敏度的气溶胶OT/环己烷/水反相胶束增稳定温荧光法,研究了中草药有效成分大黄素的荧光性质。并在最佳的实验条件下,将该法应用于血浆中痕量大黄素含量的测定。  相似文献   

10.
Keggin杂多阴离子电子结构和物化性质与中心原子的 关系   总被引:4,自引:1,他引:4  
使用密度泛函理论中的离散变分方法(DFT-DVM),以(XMo12O40)^n-(X=B,Al,Si,Ge,P,As,S)为例计算了七个Keggin杂多阴离子的电子结构,讨论了中心原子对Keggin阴离子的电子结构、稳定性、氧化还原性和酸性关系。根据计算结果,给出稳定性、氧化还原性强弱顺序,计算给出结果与实验一致。  相似文献   

11.
铁取代钨硅酸盐位壹异构体的合成、表征及电化学性质   总被引:3,自引:0,他引:3  
The four heteropoly isomers K3H2 [α-,βi-SiW11 Fe (H2O) O39]·χH2O (βi =β1,β2,β3) were prepared and Characterized by elementary analysis, IR and UV Spectroscopy. Its electrochemical behavior in aqueous solution has been discussed. The order of Polarographic half-wave potential E1/2 of heteropoly anions is as follows: β2>β1>β3>α. Its reduction process involves an one-electron reduction of Fe (Ⅲ) and a pair of two-electron reduction of W (Ⅵ). Epolidation of maleic acid with H2O2 Catalyzed by heteropoly positional isomers was studied. β3 isomers are the most active  相似文献   

12.
We have investigated a microwave-assisted synthesis of 4(3H)-quinazolinones by condensation of anthranilic acid, orthoesters (or formic acid) and substituted anilines,using Keggin-type heteropolyacids (H(3)PW(12)O(40).13H(2)O, H(4)SiW(12)O(40).13H(2)O,H(4)SiMo(12)O(40).13H(2)O or H(3)PMo(12)O(40).13H(2)O) as catalysts. We found that the the use of H(3)PW(12)O(40).13H(2)O acid coupled to microwave irradiation allows a solvent-free, rapid (approximately 13min) and high-yielding reaction.  相似文献   

13.
Lei C  Mao JG  Sun YQ  Song JL 《Inorganic chemistry》2004,43(6):1964-1968
Hydrothermal reaction of H(3)PO(3), CH(3)NH(2), zinc(II) acetate, 4,4'-bipyridine (bipy), and (NH(4))(6)Mo(7)O(24).4H(2)O at 180 degrees C led to a novel organic-inorganic layered hybrid, [CH(3)NH(3)][H(2)bipy][Zn(4)(bipy)(3)(H(2)O)(2)Mo(V)(8)Mo(VI)O(36)(PO(4))].4H(2)O (1). Its structure was established by single-crystal X-ray diffraction. It crystallizes in the monoclinic space group P2(1)/c with cell parameters of a = 17.3032(2), b = 17.8113(3), and c = 23.4597 (4) A, beta = 106.410(1) degrees, V = 6935.6(2) A(3), and Z = 4. The structure of compound 1 features a novel 2D layer built from the 8e-reduced tetracapped Keggin [Zn(4)Mo(12)O(36)(PO(4))](3)(-) anions, which are further interconnected by bridging bipy ligands. The four zinc(II) ions are in tetrahedral, trigonal bipyramidal, and octahedral coordination geometries, respectively.  相似文献   

14.
Wei M  He C  Sun Q  Meng Q  Duan C 《Inorganic chemistry》2007,46(15):5957-5966
Polyoxometalate-based metal-organic frameworks {[Gd(dpdo)(4)(H(2)O)(3)](PMo(12)O(40))(H(2)O)(2)CH(3)CN}(n) (2), {[Dy(dpdo)(4)(H(2)O)(3)](PMo(12)O(40))(H(2)O)(20CH(3)CN}(n) (3), {[Gd(dpdo)(4)(H(2)O)(3)](H(3)O)(SiMo(12)O(40))(dpdo)(0.5)(CH(3)CN)(0.5) (H(2)O)(3)}(n) (4), {[Ho(dpdo)(4)(H(2)O)(3)](H(3)O)(SiMo(12)O(40))(dpdo)(0.5)(CH(3)CN)(0.5)(H(2)O)(3)}(n) (5), {[Ni(dpdo)(2)(CH(3)CN) (H(2)O)(2)](2)(SiMo(12)O(40))(H(2)O)(2)}(n) (6), and {[Ni(dpdo)(3)](4)(PW(12)O(40))(3)[H(H(2)O)(27)(CH(3)CN)(12)]}(n) (7) (where dpdo is 4,4'-bipyridine-N,N'-dioxide) were constructed via self-assembly by embedding Keggin-type polyanions within the intercrystalline voids as guests or pillars. Compounds 2 and 3 are isomorphic and exhibit three-dimensional (3D) noninterwoven 64 frameworks with distorted-honeycomb cavities occupied by the polyanions. Compounds 4 and 5 are comprised of 3D noninterwoven frameworks formed by linking the adjacent folded sheets through hydrogen bonds and pi-pi stacking interactions relative to the free isolated dpdo ligand. Compound 6 is a pillar-layered framework with the [SiMo(12)O(40)](4-) anions located on the square voids of the two-dimensional bilayer sheets formed by the dpdo ligands and nickel(II) ions. Compound 7 is a 3D metal-organic framework formed by nickel(II) and 4,4'-bipyridine-N,N'-dioxide with the globular Keggin-structure [PW(12)O(4)](3-) anion as the template. A large protonated water cluster H(+)(H(2)O)(27) is trapped and stabilized within the well-modulated cavity.  相似文献   

15.
The title complex, [Ce(BA)3phen]2 (BA = benzoate, phen = 1,10-phenanthroline),was prepared by the reaction of Ce(NO3)3·6H2O, benzoic acid and 1,10-phenanthroline. The complex was characterized by single-crystal X-ray diffraction, elemental analysis, IR spectra and TG-DTG techniques. The results show that the crystal is of triclinic, space group P(1) with a =10.912(2), b = 11.962(3), c = 12.474(3)(A), a = 104.889(3), β = 93.523(3), γ = 113.332(3)°,C66H46Ce2N4O12, Mr = 1366.90, V= 1420.2(6) (A)3, Z = 1, Dc = 1.598 g/cm3,μ = 1.652 mm-1, S =1.024 and F(000) = 682. The final R = 0.0391 and wR = 0.0947 for 4878 observed reflections with I > 2σ(1). The structure of the title complex consists of two Ce(C6H5COO)3(C12H8N2) units,forming a binuclear molecule. Each Ce(Ⅲ) is coordinated by two O atoms of one bidentate chelating carboxylate group, five O atoms of two bidentate bridging and two tridentate chelating-bridging carboxylate groups, and two N atoms of one 1,10-phenanthroline molecule to complete a distorted monocapped square antiprism geometry. Its thermogravimetric analysis was determined by TG-DTG techniques.  相似文献   

16.
用量子化学从头计算方法, 研究了Ti8C12分别与H2O, C2H4作用形成Ti8C12(H2O)8, Ti8C12(C2H4)4的反应。计算结果表明, 在Ti8C12(H2O)8中, 电子由H2O向Ti8C12转移, 在Ti8C12(C2H4)4中, 电子由Ti8C12向C2H4转移。从Ti8C12生成Ti8C12(H2O)8能量降低, 稳定性增加, 生成Ti8C12(C2H4)4能量升高, 稳定性减小。  相似文献   

17.
The title complex, [Ce(BA)3phen]2 (BA = benzoate, phen = 1,10-phenanthroline), was prepared by the reaction of Ce(NO3)3·6H2O, benzoic acid and 1,10-phenanthroline. The complex was characterized by single-crystal X-ray diffraction, elemental analysis, IR spectra and TG-DTG techniques. The results show that the crystal is of triclinic, space group P1 with a = 10.912(2), b = 11.962(3), c = 12.474(3) , α = 104.889(3), β = 93.523(3), γ = 113.332(3)o, C66H46Ce2N4O12, Mr = 1366.90, V = 1420.2(6) 3, Z = 1, Dc = 1.598 g/cm3, μ = 1.652 mm-1, S = 1.024 and F(000) = 682. The final R = 0.0391 and wR = 0.0947 for 4878 observed reflections with I > 2σ(I). The structure of the title complex consists of two Ce(C6H5COO)3(C12H8N2) units, forming a binuclear molecule. Each Ce(III) is coordinated by two O atoms of one bidentate chelating carboxylate group, five O atoms of two bidentate bridging and two tridentate chelating-bridging carboxylate groups, and two N atoms of one 1,10-phenanthroline molecule to complete a distorted monocapped square antiprism geometry. Its thermogravimetric analysis was determined by TG-DTG techniques.  相似文献   

18.
刘杰 《结构化学》1998,17(3):225-229
采用电解法制备了未见文献报道的杂多蓝H8[SiMo11Co(H2O)O39]·20H2O,通过X-射线衍射测定了其晶体结构,该晶体属单斜晶系,空间群P21;。晶胞参数全矩阵最小二乘法修正至中心原子Si与4个氧形成四面体结构,配原子M(M=11/12Mo+1/12Co)与O形成12个MO6八面体结构3个MO6共边形成4个M3O13三金属簇,4个三金属簇与SiO4四面体共角相连形成阴离子结构。  相似文献   

19.
尿素与Keggin结构磷钼酸电荷转移盐的合成与表征   总被引:3,自引:0,他引:3  
在水中合成了两种新的有机 金属氧酸盐电荷转移配合物H3 PMo12 O4 0 ·4.5CO(NH2 ) 2 ·2 .5H2 O和H3 PMo12O4 0 ·12CO (NH2 ) 2 ,用IR、UV、TG、XRD及元素分析对其进行了表征。结果表明两种化合物中均存在[(H2 N) 2 COH]+ ,阴离子保持Keggin结构 ,但Keggin结构由于尿素的有机给体作用发生了不同程度的畸变。H3 PMo12 O4 0 ·4.5CO(NH2 ) 2 ·2 .5H2 O在固态 ,H3 PMo12 O4 0 ·12CO(NH2 ) 2 的水溶液具有光致变色效应  相似文献   

20.
本文采用DFT和TD-DFT方法研究了Keggin型多酸[SiW12O40]4-光催化劈裂水产氢气机理。计算结果显示反应主要包括四个步骤:(i) 光激发,(ii) 电荷转移和生成单电子还原(OER)中间体,(iii) 生成双电子还原(TER)中间体,(iv)氢气从多酸表面解离和催化剂重生。当第一个电子从甲醇转移到多酸后,后续反应存在均为热力学上有利的放热途径,并推动第二个电子从甲醇自由基,H[SiW12O40]4-或[SiW12O40]5-转移到OER中间体H[SiW12O40]4-或[SiW12O40]5-生成TER中间体[SiW12O40]6-,H[SiW12O40]5-或H2[SiW12O40]4-,并伴随着H2产生。耦合的电子和质子转移路径在能量上最有利。甲醇和水分子的参与有利于H2产生。多酸在整个催化循环中,扮演了光敏剂、催化剂、电子的受体和给体。  相似文献   

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