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1.
Summary.  Oxo peroxo glycolato complexes of vanadium(V) (M 2[V2O2(O2)2(C2H2O3)2nH2O (n=0, 1; M=NBu4 + (1), K+ (2), NH4 + (3), Cs+ (4), NPr4 + (5)) as well as (NBu4)2[V2O4(C2H2O3)2]ċ H2O (6) have been prepared and characterized by spectroscopic methods. X-Ray structure analysis of 1 revealed the presence of dinuclear [V2O2(O2)2(C2H2O3)2]2− anions with a (chemical structure) bridging core and six coordinated vanadium(V) atoms in a distorted pentagonal pyramidal array. Received July 12, 1999. Accepted (revised) October 28, 1999  相似文献   

2.
A new iron(III)/vanadium(III) phosphate, K3[Fe3.26V0.74(OH)O(PO4)4(H2O)2]·2H2O (1), has been obtained by hydrothermal synthesis and characterized by single crystal X-ray diffraction, Scanning electron microscopy–energy dispersive X-ray spectroscopy, Inductively coupled plasma atomic emission spectroscopy (ICP), thermogravimetric analysis, and FTIR spectroscopy. Single crystal X-ray diffraction reveals a 3D open framework (monoclinic, space group P21/n, a?=?9.6391(7)?Å, b?=?9.8063(7)?Å, c?=?9.7268(7)?Å, β?=?100.71(1)°, and V?=?903.38(11)?Å3). This structure presents FeIII and VIII in a 4.4?:?1?M ratio with the metal ions in two different crystallographic sites. Both metallic centers have distorted octahedral environments, linked by PO4 tetrahedra, forming channels along the a-axis. The asymmetric unit of K3[Fe3.26V0.74(OH)O(PO4)4(H2O)2]·2H2O presents a {M4(OH)O(PO4)4(H2O)2}3? anionic entity, charge balanced by three K+, which are located within the channels. It is also possible to distinguish M4O2 units whose MIII polyhedra are linked by vertex and edges.  相似文献   

3.
以Co(NO3)2,2,2'-联吡啶(2,2'-bipy)及NaVO3为原料,采用水热法于200 ℃合成了一种新的有机-无机杂化材料--Co(2,2'-bipy)(H2O)V2O6(1),其结构经IR,热重分析及X-射线单晶衍射表征.结果表明,1属于单钭晶系,空间群为P21/c,晶胞参数为:a=7.855 6(3)(A),b=21.056 2(5)(A),c=9.552 1(6)A,α=90.000°,β=110.236(5)°,γ=90.000°,V=1 423.65(8)(A)3,Z=2,Dc=2.126 g·cm-3,μ(Mo Kα)=2.548mm-1,R1=0.058 6,wR2=0.093 5.1为一种二维层状结构,由[VO4]四面体通过共顶点构成的一维钒氧链,链与链之间以[Co(2,2'-bipy)(H2O)]2 基团连接而成.  相似文献   

4.
《Polyhedron》1999,18(21):2781-2785
The compounds (NH4)6[Mo6V2O24(C2O4)2]·6H2O (I) and (NH4)4[H2Mo2V2O12(C2O4)2]·2H2O (II) have been prepared from molybdenum(VI) oxide and ammonium vanadate in aqueous solution through the addition of ammonium oxalate, and their structures determined by X-ray structure analysis. Whereas the molybdovanadate anion [Mo6V2O24(C2O4)2]6− found in (I) consists of six MoO6 and two VO6 edge-sharing octahedra of the γ-[Mo8O26]4− type structure, the tetranuclear anion [H2Mo2V2O12(C2O4)2]4− of (II) adopts the structure with a M4O16 core. Both complexes contain bidentate oxalato ligands bonded to the vanadium ions. In both crystal structures the molybdovanadate anions are mutually hydrogen bonded by ammonium ions and water molecules.  相似文献   

5.
采用硝酸锌、五氧化二钒和氢氧化钠作为反应物,通过一个简单的CTAB辅助的水热方法制备了Zn3(OH)2V2O7·2H2O纳米片.运用XRD,ICP-AES,FTIR,HRTEM,EDS,FE-SEM对产物的晶相和形貌进行了表征.结果表明CTAB在控制产物的形貌、尺寸分布和自组装过程中起着关键作用.同时我们研究了产物的晶体生长行为和自组装过程.  相似文献   

6.
Summary Triisopropoxy bis(O,O-dialkyl dithiophosphates), (i-PrO)3M[S2P(OR)2]2 (M = Nbv, Tav; R = n-Pr, i-Pr, i-Bu and Ph) have been prepared by reacting the appropriate triisopropoxymetal(V)dichloride, (i-PrO)3MCl2 (1 mol) with sodium/ammonium dialkyl dithiophosphates (2 mols)in THF. The monomeric products which are viscous liquids, soluble in common organic solvents and highly susceptible to hydrolysis, were characterized by i.r. and n.m.r. spectra which indicate a bidentate mode of attachment of dithiophosphato groups to the metal.  相似文献   

7.
Peroxovanadium(V) complexes of -hydroxyhippuric acid (-H2hhip), M 2[V2O2(O2)2(-hhip)2nH2O, [M=K+ (1), NH4 + (2), NEt 4 + (3), NBu 4 + (4); n=5.5, 3, 8, 5) have been prepared and characterized by elemental analysis, i.r., u.v.–vis. and 51V-n.m.r. spectroscopies and by thermal analysis. The X-ray structure determination of (4) revealed the presence of dinuclear [V2O2(O2)2(R--hhip)(S--hhip)]2– anions with a planar V2O2 bridging core and seven-coordinated central atoms. The coordination geometry of the vanadium atom is a distorted pentagonal bipyramid.  相似文献   

8.
Two new decavanadate metal complexes, [Co(H2O)6]2[H2V10O28]·6H2O (1) and (NH4)2[Ca(H2O)7]2[V10O28] (2), have been synthesized under hydrothermal condition by using chlorhydric acid as the initiator at 120 °C. The aqueous NaVO3 solution with an aqueous solution of CoCl2·6H2O were used for generating 1 and aqueous CaCl2·2H2O and NH4VO3 solution were employed for creating 2. Compound 1 consisted of discrete hexa-aqua-cobalt [Co(H2O)6]2+ cations, [H2V10O28]4− anions and non-coordination water molecules. Compound 2 were composed of hepta-aqua-calcium [Ca(H2O)7]2+ cations, ammonium NH4 + and [V10O28]6− anion. For compound 2, the distorted pentagonal bipyramid [Ca(H2O)7]2+ is uncommon. In the crystal lattice, hydrogen bonds played an important role on connecting cations, anions and non-coordinated water molecules to form the three-dimensional network.  相似文献   

9.
Trichloro- and triisopropoxy-niobium(V) and tantalum(V) alkylene dithiophosphates, (M = Nb(V) or Ta(V); G =–CHMeCHMe–,–CMe2CMe2–,–CH2CMe2CH2–,–CH2CEt2CH2–or–CMe2CH2CHMe–and X = Cl or OPri) have been synthesized by reaction of metal(V) chloride, MCl5, or triisopropoxymetal(V) dichloride, (PriO)3MCl2, with the sodium salts of O,O′-alkylene dithiophosphoric acids, in 1 : 2 molar ratio in THF under anhydrous conditions. These pink-purple or light-yellow compounds are viscous, semi-solid or solid, hydrolyzable and soluble in common organic solvents. These compounds have been characterized by elemental analyses, molecular weight determinations and spectral studies like IR and heteronuclear NMR (1H, 13C and 31P), which indicated a bidentate mode of chelation of dithio ligands, leading to a pentagonal bipyramidal geometry around the niobium(V) or tantalum(V) centers.  相似文献   

10.
Compound [V16O38(Cl)][Cu(enMe)2]3.5*2H2O(1) has been hydrothermally synthesized and characterized by means of single-crystal X-ray diffraction, elemental analysis, IR, EPR and TGA analysis. The X-ray crystallography shows that compound 1 contains a new {V16O38} cluster shell, which is connected by [Cu(enMe)2]2 coordination fragments into a 3-D framework. The compound crystallized in a monoclinic system with space group P2(1)/n, M=2235.82, a=1.26076(3) nm, b=2.55802(6) nm, c=2.14742(4) nm, β=90.7380(10)°, V=6.9250(3) nm3, Z=4, F(000)=4418, Dc=2.145 g*cm-3, μ=3.227 mm-1,(Δ/σ)=0.000, S=1.066.  相似文献   

11.
Three new poloxovanadates were synthesized under solvothermal conditions and were structurally characterized. The two compounds with composition {Ni(dien)(2)}(3)[V(15)Sb(6)O(42)(H(2)O)]·nH(2)O (n = 12 and 8; dien = bis(2-aminoethyl)amine or diethylenetriamine) are pseudopolymorphs crystallizing in different space groups. The compounds were obtained by applying identical reaction slurries but using different reaction temperatures. Both compounds feature the [V(15)Sb(6)O(42)(H(2)O)](6-) anion which is the antimony analogue to the single molecule magnet [V(15)As(6)O(42)(H(2)O)](6-). Crystal data: 1 tetragonal space group P4, a = 46.9378(3), c = 16.51300(10) ? and V = 36380.7(4) ?(3). 2 rhombohedral space group R3c with a = 23.0517(4), c = 28.6216(5) ? and V = 13171.3(4) ?(3). In 1 several unusual short inter-cluster Sb···O contacts lead to the formation of three different super-clusters with composition V(60)Sb(24)O(168). The 12 unique {Ni(dien)(2)}(2+) complexes adopt all three possible configurations. In 2 the special arrangement of the {Ni(dien)(2)}(2+) complexes around the cluster anion prevents inter-cluster Sb···O contacts. The main structural motif of the third compound {Ni(dien)(2)}(4)[V(16)Sb(4)O(42)(H(2)O)] (3) is the [V(16)Sb(4)O(42)(H(2)O)](8-) cluster anion consisting of two perpendicular eight-membered rings of VO(5) pyramids. Two additional VO(5) polyhedra are located on opposite sides. Crystal data: 3 triclinic space group P1 = 13.5159(4), b = 14.2497(5), c = 14.9419(4) ?, α = 98.322(2), β = 114.080(2), γ = 110.130(2)° and V = 2326.35(12) ?(3).  相似文献   

12.
V2O5/TiO2催化剂表面结构FT-IR发射光谱研究(II)   总被引:2,自引:0,他引:2  
用傅里哀变换红外发射光谱原位考察了V_2O_5/TiO_2催化剂在制备焙烧过程中担载偏钒酸铵的热分解步骤及其形成的表面活性相结构。偏钒酸铵在200 ℃左右分解, 在300 ℃之前完全转化为晶相V_2O_5。担载于TiO_2上的偏钒酸铵在100 ℃左右与TiO_2已产生强的化学作用, 在200 ℃之前已完全分解。对于10%(质量分数)V_2O_5/TiO_2催化剂其担载偏钒酸分解后在1020 cm~(-1)附近出现晶相V_2O_5的特征峰。但在500 ℃进一步焙烧后晶相V_5O_5的峰减弱并在1025—900 cm~(-1)区出现宽峰, 表明部分晶相V_2O_5可能转化为二维高分散的VO_x物种。2%(质量分数)V_2O_5/TiO_2催化剂在焙烧过程中也显示晶相V_2O_5的弱峰, 但同时也观察到属于VO_x物种的宽峰。进一步降低钒担载量, V_2O_5晶相特征峰逐渐消失, 而在1025—900 cm~(-1)区出现二维VO_x物种的宽峰。结果还表明傅里哀变换红外发射光谱是表征氧化物催化剂表面相结构的一种有力的方法。  相似文献   

13.
Vanadium dioxide (VO2) was directly synthesized via the reduction of V2O5 with oxalic acid adopting two different types of hydrothermal processes in the temperature ranging from 180 to 260 °C. The products were characterized by X-ray diffraction, field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). In all these processes, the VO2(B) phase was first formed at a relative lower temperature or the initial stage at higher temperature and then it transformed to the VO2(R) phase with the increase of temperature. The building-block-stacking mechanism was proposed to elucidate the transformation from VO2(B) nano-plates to snowflake-like VO2(R) powders. During this transformation, no trace of the VO2(A) phase was observed when one-step hydrothermal treatment method was used, whereas some part of the branches of the snowflake-like VO2(R) particles transformed to metastable VO2(A) nanofibers in the autoclave during cooling process when the two-step hydrothermal treatment method was conducted. The reason for this transformation can be contributed to the defects formed during the stacking process.  相似文献   

14.
金属氧酸盐因其在医药临床、工业催化、功能材料等方面的广泛应用而引起人们的关注[1~6], 其中, 有关钒化学的研究一直很活跃, 钒具有与钼、钨明显不同的结构特性, 钒可以采取VO4, VO5和VO6方式配位, 同时, 钒的价态可以是+3, +4和+5价. 由于钒可采取多种配位方式及多种价态, 与钼酸盐和钨酸盐相比, 钒酸盐更具有结构柔顺性, 同时易形成低价或混合价态物种.在以往的文献中, 有关P-V-O体系多金属氧酸盐的水热合成的研究已有大量的报道[7], 在常规溶液合成中, 人们已对As-V-O体系进行了相对深入的研究, 而有关水热合成的研究报道却很少, 已见报道的砷钒化合物有K6*6H2O[8,9], 4-[10], 6-[11](X=SO2-3, SO2-4, H2O). 为了探究水热条件下As-V-O体系的反应特性, 我们开展了这方面的研究工作, 并取得了突破性进展. 本文采用中温水热技术合成了含有机基团的砷矾超分子化合物2**4H2O, 探讨这类化合物的非线性光学性质、催化性质及其它功能特性将是一个非常有意义的研究领域.  相似文献   

15.
Abstract

Reactions of Mo(CO)6 with Na2WO4 · 2H2O in refluxing carboxylic anhydride produce the triangular bioxo-capped mixed-metal carboxylate clusters Na[MoW2O2(O2CR)9] (R = Me, 1; Et, 2), the propionate being hydrolyzed in 2M HCl containing ZnCl2 to form [MoW2O2(O2CEt)6(H2O)3]ZnCl4·2H2O (3). Cluster 2 is converted to the incomplete cuboidal tetraanion [MoW2O4(O2CEt)8]4- upon reacting with Cr(CO)6 in propionic anhydride at 120°, the latter species being trapped by Cr and Na± ions in the reaction mixture to afford the octanuclear heterometallic chain-like cluster Na2Cr2 [MoW2O4(O2CEt)8]2 (4). Clusters 1, 3 and 4 have been characterized by X-ray crystallography with the following crystal data, for 1: monoclinic, space group P21/c, a = 16.666(8), b = 11.096(3), c = 16.541(7) Å, β = 94.60(4)°, V = 3048.9 Å3, Z = 4, R, Rw = 0.070, 0.079; for 3, monoclinic, space group Cm, a = 10.259(3), b = 15.756(3), c = 10.870(3) Å, β = 96.18(3)°, V = 1746.8 Å3, Z = 2, R, Rw = 0.028, 0.034; for 4, triclinic, space group P-1, a = 13.013(5), b = 14.005(4), c = 12.357(4) Å, α = 109.71(2), β = 117.77(3), γ = 90.41(3)°, V = 1838.9 Å3, Z = 1, R, Rw = 0.037, 0.042.  相似文献   

16.
Anthracene and its alkyl derivatives undergo oxidation in the V(V)/H2O2/AcOH system via a nonradical mechanism through the intermediate formation of the vanadium(V) complex with singlet dioxygen as a ligand. The 1O2molecule is transferred from this complex to an unsaturated substrate. The free singlet dioxygen 1O2(1 g ) is almost inactive toward anthracene in AcOH solution. Consequently, the vanadium(V) complex with singlet dioxygen is the only oxidant species active in the reaction. The ratio between the rate constant of the reaction of this complex with 2-ethylanthracene and the rate constant of its deactivation is an order of magnitude greater than the ratio between the rate constant of the reaction of dissolved free singlet dioxygen with the same substrate and the rate constant of its deactivation (physical quenching).  相似文献   

17.
Two new polyoxovanadates (Co(N(3)C(5)H(15))(2))(2)[{Co(N(3)C(5)H(15))(2)}V(15)Sb(6)O(42)(H(2)O)]·5H(2)O (1) and (Ni(N(3)C(5)H(15))(2))(2)[{Ni(N(3)C(5)H(15))(2)}V(15)Sb(6)O(42)(H(2)O)]·8H(2)O (2) (N(3)C(5)H(15) = N-(2-aminoethyl)-1,3-propanediamine) were synthesized under solvothermal conditions and structurally characterized. In both structures the [V(15)Sb(6)O(42)(H(2)O)](6-) shell displays the main structural motif, which is strongly related to the {V(18)O(42)} archetype cluster. Both compounds crystallize in the triclinic space group P1 with a = 14.3438(4), b = 16.6471(6), c = 18.9186(6) ?, α = 87.291(3)°, β = 83.340(3)°, γ = 78.890(3)°, and V = 4401.4(2) ?(3) (1) and a = 14.5697(13), b = 15.8523(16), c = 20.2411(18) ?, α = 86.702(11)°, β = 84.957(11)°, γ = 76.941(11)°, and V = 4533.0(7) ?(3) (2). In the structure of 1 the [V(15)Sb(6)O(42)(H(2)O)](6-) cluster anion is bound to a [Co(N(3)C(5)H(15))(2)](2+) complex via a terminal oxygen atom. In the Co(2+)-centered complex, one of the amine ligands coordinates in tridentate mode and the second one in bidentate mode to form a strongly distorted CoN(5)O octahedron. Similarly, in compound 2 an analogous NiN(5)O complex is joined to the [V(15)Sb(6)O(42)(H(2)O)](6-) anion via the same attachment mode. A remarkable difference between the two compounds is the orientation of the noncoordinated propylamine group leading to intermolecular Sb···O contacts in 1 and to Sb···N interactions in 2. In the solid-state lattices of 1 and 2, two additional [M(N(3)C(5)H(15))(2)](2+) complexes act as countercations and are located between the [{M(N(3)C(5)H(15))(2)}V(15)Sb(6)O(42)(H(2)O)](4-) anions. Between the anions and cations strong N-H···O hydrogen bonds are observed. In both compounds the clusters are stacked along the b axis in an ABAB fashion with cations and water molecules occupying the space between the clusters. Magnetic characterization demonstrates that the Ni(2+) and Co(2+) cations do not significantly couple with the S = 1/2 vanadyl groups. The susceptibility data can be successfully reproduced assuming a distorted ligand field for the Co(2+) ions (1) and an O(h)-symmetric Ni(2+) ligand field (2).  相似文献   

18.
Hexaaquachromium(III) trihydrogen isopolyvanadate [Cr(H2O)6]H3[V10O28] · 2H2O (I) was obtained and examined by mass spectrometry, X-ray powder diffraction, thermogravimetry, and IR and NMR spectroscopy. The crystals are monoclinic, space group $P\bar 1$ a = 7.862(3), b = 8.427(5), c = 5.000(2) Å, β = 96.46(4)°, V = 867.0(3) Å3, ρcalcd = 5.83 g/cm3, Z = 1.  相似文献   

19.
Raman spectroscopy has been used to study the molecular structure of the vanadate mineral pascoite. Pascoite, rauvite and huemulite are examples of simple salts involving the decavanadate anion (V10O28)6-. Decavanadate consists of four distinct VO6 units which are reflected in Raman bands occurring at higher wavenumbers. The Raman spectrum of pascoite is characterised by two intense bands at 991 and 965 cm(-1). Raman bands are observed at 991, 965, 958 and 905 cm(-1) and originate from four distinct VO6 sites in the mineral structure. In the infrared spectra of pascoite, two wavenumber regions are observed between: (1) 837 and 860, and (2) between 803 and 833 cm(-1). These bands are assigned to ν3 antisymmetric stretching modes of (V10O28)6- or (V5O14)3- units. The spectrum is highly complex in the lower wavenumber region, and therefore the assignment of bands is difficult. Bands observed in the 404 to 458 cm(-1) region are assigned to the ν2 bending modes of (V10O28)6- or (V5O14)3- units. Raman bands observed in the 530-620 cm(-1) region are assigned to the ν4 bending modes of (V10O28)6- or (V5O14)3- units. The Raman spectra of the vanadates in the low wavenumber region are complex with multiple overlapping bands which are probably due to VO subunits and MO bonds.  相似文献   

20.
Reaction of (C2H5)2SnCl2 with the trilacunary 9-tungstoarsenate(V) [A–α–AsW9O34]9? in aqueous pH 5 medium resulted in the diethyltin-containing polyanion [{Sn(C2H5)2}3(H2O)6(A–α–AsVW9O34)]3? (1), which crystallized as a hydrated guanidinium salt, [C(NH2)3]3[{Sn(C2H5)2}3(H2O)4(A–α–AsVW9O34)]·9H2O (1a). Polyanion 1 represents the first example of a diethyltin-containing polyanion. The diethyltin groups are bound to the trilacunary Keggin units via two Sn–O(W) bonds involving edge-shared WO6 octahedra. Each Sn atom also has two terminal, cis-related water ligands, and two terminal, trans-related ethyl groups. Multinuclear (1H, 13C, 119Sn, 183W) NMR spectrometry indicated that polyanion 1 is stable in solution. Compound 1a was structurally characterized in the solid state by single-crystal XRD, FT-IR, as well as thermogravimetric and elemental analyses. Single-crystal X-ray analysis showed that 1a crystallizes in the orthorhombic system, space group P nma , with a = 23.5280(10) Å, b = 15.5435(6) Å, c = 18.6191(9) Å, V = 6809.1(5) Å3 and Z = 4. The structure of 1a is an extended 2D assembly of individual polyanion units 1 linked via Sn–O(W) bridges.  相似文献   

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