杂多酸盐(TBA)_n[XW_9Mo_2(CH_3SiOSiCH_3)O_(39)]的合成和表征

具有Keggin衍生结构,以α-[SiW_(11)(RSiOSiR)O_(39)]~(4-)(R=C_2H_5、C_6H_5、NC(CH_2)_3、C_3H_5)为阴离子的杂多酸盐已有报道,但以[XW_9Mo_2(RSiOSiR)O_(39)]~(n-)为阴离子的杂多酸盐尚未见报道。本文首次合成六种以[XW_9Mo_2(CH_3SiOSiCH_3)O_(39)]~(n-)以及[XW_(11)(CH_3SiOSiCH_3)O_(39)]~(n-),(X=Si,P,Ge)为阴离子的杂多酸四丁基铵(TBA)盐,并对它们进行了表征。     

杂多三金属磷酸盐的合成与表征

早期合成的Keggin结构杂多酸均是同种齿顶原子,后来人们合成了一系列含两种齿顶原子的三元杂多酸~[1,2],我们曾制备了含3种齿顶原子的四元杂多酸~[3,4].随着齿顶原子种类的增多,杂多酸在水溶液中的稳定性降低.本文采用空缺杂多酸阴离子逐步与不同齿顶原子结合,最后用溶解度极小的(C_1H_9)_4N~+盐沉淀方法合成了未见报道的磷的四元杂多酸盐.     

钨钼钒硅杂多酸盐的合成及表征

本文合成了一类未见报道的含三种齿顶原子的钨钼钒硅酸四丁基铵(TBA)盐,它们是:(TBA)_4[HSiW_9Mo_2VO_(40)]和(TBA)_4[H_2SiW_9MoV_2O_(40)]。红外光谱与已知的β-(TBA)_4[SiW_9Mo_3O_(40)]相似,故它们具有β-Keggin结构。在固态时,由于离子间的库仑作用,使TBA变形,从而削弱了C—N键。由C—N键的伸缩频率变化可知β-[TBA)_4[H_2SiW_9MoV_2O_(40)]和β-(TBA)_4[H_3SiW_9V0_(40)]为酸式盐。由X光衍射和差热曲线证明上述两种三齿顶杂多酸盐存在着几何异构体。     

九钨三锰硅酸钾异构体的合成及其转移氧原子的性质

Hill~[1],Finke~[2]和Neumann~[3]曾分别报道[Pw_(11)O_(39)M]~(n-)、[P_2W_(17)O_(61)M]~(n-)和[SiW_(11)O_(39)Ru]~(5-)具有催化烯烃环氧化反应的性质,三取代的Keggin杂多阴离子有相似的性质.本文首次报道α-和β-K_6H_4[SiW_9O_(37)Mn_3(H_2O)_3]·xH_2O的合成及其转移氧原子的性质,为研究杂多酸盐的催化提供了一个新的含锰杂多阴离子.     

Studies on the Redox Properties of Undecatungstotitanates Containing One Kind of Transition Metal

Some monosubstituted Keggin or Dawson anions nave been reporten by Hill to be "remarkably effective" catalysts for the epoxidation of alkenes, Hill, Finke and Neumann reported respectively that the transition metal monosubstituted heteropolyanions [PW_(11)O_(39)M(H_2O)]"~-, [P_2W_(17)O_(61)M(L)]"- and [SiW_(11)O_(39)Ru(H_2O)]~(37-) have an ability to catalyze the epoxidation of alkenes. And the undecatungstotitanates with one kind of transition metal have     

包含银的Keggin型锗钼酸盐[NH_4]_2[Ag(H_2O)(H_2PDCA)]_2[α-GeMo_(12)O_(40)]·12H_2O（英文）

利用常规水溶液方法合成了一种有机-无机杂化的包含银的Keggin型锗钼酸盐[NH_4]_2[Ag(H_2O)(H_2PDCA)]_2[α-GeMo_(12)O_(40)]·12H_2O(1),并通过元素分析、红外光谱和单晶X射线衍射等对其进行了表征.X射线晶体学研究表明化合物1的分子结构由1个典型的Keggin结构[α-GeMo12O40]~(4-)聚阴离子、2个[Ag(H_2O)(H_2PDCA)]~+配离子、2个NH+4离子和12个结晶水分子构成.值得注意的是在[α-GeMo_(12)O_(40)]~(4-)单元中,锗原子呈现出立方体几何配位构型,这归结于与锗原子相连的每个氧原子都无序地排列在两个位置.有趣的是,每个[α-GeMo_(12)O_(40)]~(4-)多阴离子通过4个[Ag(H_2O)(H_2PDCA)]~+桥配离子与4个[α-GeMo_(12)O_(40)]~(4-)多阴离子相连构筑了二维层状结构.此外,我们还在室温下研究了化合物1的电化学性质.     

杂多酸盐(TBA)n[XW9Mo2(CH3SiOSiCH3)O39]的合成和表征

具有Keggin衍生结构,以α-[SiW₁₁(RSiOSiR)O₃₉]^4-(R=C₂H₅、C₆H₅、NC(CH₂)₃、C₃H₅)为阴离子的杂多酸盐已有报道^[1],但以[XW₉Mo₂(RSiOSiR)O<     

一例基于Keggin型多酸阴离子的双加帽杂多铌酸盐的合成、结构及表征

在水热条件下,成功合成了一例基于Keggin型多酸阴离子的双加帽杂多铌酸盐[Ni(en)_3]_3[Ni(en)_2(H_2O)_2]_2H[VNb_(12)O_(40)(VO)_2]·10H_2O(1),并通过红外光谱、热重分析和X射线单晶衍射等方法对该化合物进行了表征.X射线单晶衍射分析表明,化合物1属于正交晶系,Pna2(1)空间群,晶胞参数a=3.051 7(3)nm,b=1.561 0(1)nm,c=2.271 9(3)nm,V=10.823(3)nm~3.化合物1包含1个Keggin型聚阴离子[VNb_(12)O_(40)(VO)_2]~(11-)和3个镍配离子.在阴离子结构中,中心钒原子被12个铌原子包围形成经典Keggin型结构的[VNb_(12)O_(40)]~(15-)阴离子,另外两个{VO}基团分别加帽于[VNb_(12)O_(40)]~(15-)阴离子的两端.     

51VNMR研究磷钼钒系杂多酸的热稳定性

用NMR及IR、TG-DTA等手段研究具有Keggin结构的磷钼钒系杂多酸在空气中的热稳定性。实验结果表明:合成的杂多酸在各个Keggin单元中具有不同的钒含量。样品的热稳定性与其钒含量有关.随着钒含量的增加,keggin结构的热稳定性逐渐降低,但H_4PMo_(11)V_1O_(40)具有比H_3PMo_(12)O_(40)还要高的热稳定性。由于钒的取代,钼钒磷酸的热分解过程不同于钼磷酸。失去结构水使Keggin结构遭到破坏,但在室温下与水重新作用可使钼钒磷酸的Keggin结构恢复。     

含氧桥的笼状化合物[Mo_5P_2O_(23)]~(6-)[(CH_3)_2NH_2]_5~(5+)-[H_3O]~+·1/2(CH_3)_2NCHo·1/2H_2O的合成和结构

[Mo_5P_2O_(23)]~(6-)[(CH_3)_2NH_2]_5~(5+)[H_3O]~+·1/2DMF·1/2H_2O(DMF=(CH_3)_2NC-HO)(M_r=1204.67)的晶体属三斜晶系,空间群P,晶胞参数a=16.438(6);b=22.22(1);c=11.325(5),α=104.25(4);β=108.97(3);γ=97.68(4)°,V=3688(3),Z=4,D_c=2.17gcm~(-1),R=0.056,R_w=0.074,晶胞中每个不对称单元含有两个[Mo_5P_2O_(23)]~(6-)[(CH_3)_2NH_2]_5~(5+)[H_3O]~+·1/2DMF·1/2H_2O,阴离子[Mo_5P_2O_(23)]~(6-)中的Mo、P原子成一个畸变五角双锥构型。有一个阴离子的所有原子(Mo、P、O)位置完全确定,而另一个阴离子有一个磷酸根的三个氧原子位置出现二重位置统计分布。化合物的阳离子为二甲胺阳离子和水合氢离子。     

过氧铌杂多钨酸盐热分解动力学参数的测定

钼和钨的杂多配合物由于其高催化活性及抗病毒性吸引着人们的关注［１］。杂多配合物的组成改变能调变其酸性、氧化性、反应性等,因此,混配型杂多配合物的研究近二十年来十分活跃。铌取代的杂多配合物在催化方面具有很独特的性质,其催化的工业应用及其机理已引起广泛的兴趣［２］。我们发现,过氧铌杂多配合物比非过氧杂多配合物具有更高的催化活性［３］。杂多酸盐的热稳定性是影响多相催化活性的重要性质,迄今有关过氧杂多配合物的热性质和热分解反应动力学参数的研究未见报道。本文用ＴＧ、ＤＴＡ、ＤＳＣ溶解度试验,变温红外和Ｘ一…     

Si取代Keggin型多酸催化光解水产氢机理

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。     

3D-transition metal mono-substituted Keggin polyoxotungstate with an antenna molecule: synthesis, structure and characterization

Three new organic-inorganic hybrid complexes based on 3d-transition metal monosubstituted Keggin polyoxometalates (POMs) with imidazole (Im) as pendant ligands, formulated as (HIm)(6-)[SiW11O39NiIm]0.8[SiW11O39Ni(H2O)]0.2.7H2O (1), (Im)4Na6[SiW11O39MnIm]0.69[SiW11O39Mn(H2O)]0.31.7.5H2O (2) and (HIm)6[SiW11O39CoIm]0.63[SiW11O39Co(H2O)]0.37.7H2O (3), have been synthesized and characterized by IR spectroscopy, UV-visible spectroscopy, elemental analysis, TG analysis, cyclic voltammetry, magnetic properties, EPR and single-crystal/powder X-ray diffraction. The structural analyses indicate that the 3d metal atoms are incorporated into the vacancy of the alpha-[SiW11O39](8-) (SiW11). Complexes 1-3 are the first examples of crystallographically characterized 3d-transition metal mono-substituted POMs with an antenna organic ligand synthesized under normal bench conditions.     

Cation-controlled assembly of Na+-linked lacunary alpha-Keggin tungstosilicates

Two novel salts of lacunary tungstosilicates with guanidinium and alkali metal cations, (CH6N3)7Na[SiW11O39].(CH3)2CO.8H2O (1) and (CH6N3)K6Na[SiW11O39].11.5H2O (2), have been synthesized and their crystal structures have been determined by synchrotron X-ray diffraction. In both crystals, the Na+ cations link the lacunary Keggin-type tungstosilicate anions into linear structures. The neighboring [SiW11O39]8- anions are related by two-fold screw and translational operations in compounds 1 and 2, respectively. Second harmonic generation was observed for compound 1.     

4[CuCl(C5H5N)4]·[W10O32]·2(C5H5N)·3H2O的合成及晶体结构

标题化合物是通过(NH_4)_2WS_4, CuCl_2·2H_2O在吡咤溶液中反应制得。晶体呈蓝色, 属三斜晶系, 空间群P1, 晶胞参数为:a=1.3555(7), b=1.3666(5), c=1.7860(13) nm, α=69.08(4)°, β=87.39(5)°, γ=70.72(4)。V=2.907(3) nm, Z=1, D_m=2.56 g cm~(-3)。结构由Patterson法和Fourier法测出。对5692个收集到的独立衍射数据进行计算, 最后R=0.046。结构测定表明, 晶体由W_(10)O_(32)~(4-), [CuCl(C_5H_5N)_4]~+, C_5H_5N和H_2O所组成。W_(10)O_(32)~(4-)的结构见图1, W原子处在O原子的八面体配位中, 彼此共边和共顶点相连。[CuCl(C_5H_5N)_4]~+的结构见图2, Cu原子由1个Cl和4个N原子配位, 呈略有变形的四方锥形, 这种离子是首次报导。C_5H_5N和H_2O填入正负离子堆积的空隙中。     

Hybrid inorganic-metalorganic compounds containing copper(II)-monosubstituted Keggin polyanions and polymeric copper(I) complexes

Four hybrid inorganic-metalorganic compounds containing copper(II)-monosubstituted Keggin polyoxotungstates, K3[Cu(I)(4,4'-bpy)]3[SiW11Cu(II)O39].11H2O (1), (paraquat)3[SiW11Cu(II)O39].6H2O (2; paraquat = N,N'-dimethyl-4,4'-bipyridinium), K3[Cu(I)(4,4'-bpy)]3[GeW11Cu(II)O39].11H2O (3), and Na2[Cu(I)(4,4'-bpy)]3[PW11Cu(II)O39(H2O)].4H2O (4), have been synthesized under autogenous pressure hydrothermal conditions and characterized by elemental analysis and infrared spectroscopy (FT-IR). The crystal structures of 1, 2, and 4 have been established by single-crystal X-ray diffraction. The crystal packings are characterized by the presence of monodimensional extended entities: either the polymeric polyanion [SiW11CuO39]n(6n-) (2), the cationic [Cu(4,4'-bpy)]n(n+) chain (4), or both simultaneously as in compound 1, where the inorganic and metalorganic sublattices are mutually perpendicular. To asses the influence of packing in the copper(I) complex structural diversity found in compounds 1 and 4, a search in the CSD database has been performed and the resulting geometrical features have been analyzed and compared with experimental crystallographic data and DFT calculations.     

Cation-directed synthesis of tungstosilicates. 1. Syntheses and structures of K10A-alpha-[SiW9O34].24H2O,of the sandwich-type complex K10.75[Co(H2O)6]0.5[Co(H2O)4Cl]0.25A-alpha-[K2(Co(H2O)2)3(SiW9O34)2].32H2O and of Cs15[K(SiW11O39)2].39H2O

The influence of the nature of alkali metal cations on the structure of the species obtained from the trivacant precursor A-alpha-[SiW(9)O(34)](10-) has been studied. Starting from the potassium salt 1, K(10)A-alpha-[SiW(9)O(34)].24H(2)O, the sandwich-type complex 2, K(10.75)[Co(H(2)O)(6)](0.5)[Co(H(2)O)(4)Cl](0.25)A-alpha-[K(2)(Co(H(2)O)(2))(3)(SiW(9)O(34) )(2)].32H(2)O, has been obtained. The crystal structures of these two compounds consist of two A-alpha-[SiW(9)O(34)](10-) anions linked by a set of potassium (1) or cobalt plus potassium cations (2), and the relative orientation of the two half-anions is the same. Attempts to link two A-alpha-[SiW(9)O(34)](10-) anions by tungsten atoms instead of cobalt failed whatever the alkali metal cation. Moreover, the nondisordered structure of Cs(15)[K(SiW(11)O(39))(2)].39H(2)O is described. Two [SiW(11)O(39)](8-) anions are linked through a potassium cation with a "trans-oid" conformation, and the potassium occupies a cubic coordination site.     

fac-mer-[Co(β-ala)3]的异构化反应动力学

The isomerization products of fac- and mer-[Co(β-ala)_3] in neutral and acidic media were separated with Na~+-type SP-Sephaex C-25 column and determined by spectrophotometry. At high temperatures(>90 ℃)the fac-isomer readily isomerizes to mer-[Co(β-ala)_3] and simultaneously hydrolyzes to yield a brown slurry in neutral solution.However, in acidic solution hydrolysis does not occur, the products are mer-isomer and a small amount of red complex cation, which is strongly adsorbed at the top of SP-Scphadex column and would probably be the fac-[Co(β-ala)_2[Co(β-alaH)(H_2O]~+.At 90 ℃ the mer-[Co(β-ala)_3]is hydrolyzed rapidly to yield a brown precipitate in neutral solution and isomerizes in small amount to fac-isomer. In acidic solution the mer-isomer isomerizes slightly to fac-isomer, and at the top of SP-Sephadex column, a violet complex cation which would probably be mer-[Co(β-ala)_2(β-alaH)(H_2O]~+ is abserved.The kinetic parameters of isomerization of fac-[Co(β-ala)_3] in neutral, basic and acidic solutions have been determined with spectrophotometric method at 534 nm. The resufts obtained indicate that reaction rates v with respect to fac-[Co(β-ala)_3] in neutral, basic and acidic media are all in first order, and under constant initial concentration of fac-[Co(β-ala)_3] the reaction rates v with respect zation of fac-[Co(β-ala)_3] in neutral, [OH~-]=4.04×10~(-4) molL~(-1), [HCl]=1.56×10~(-2) molL~(-1) and [HClO_4]=1.56×10~(-2) molL~(-1) media at 90 ℃ are 0.0195, 57.3, 3.43 and 0.978 min~(-1) while the activation energies are 194.2, 103.1, 134.1 and 113.8 kJ.mol~(-1) respectively.     

About the Keggin isomers: crystal structure of [N(C4H9)4]-gamma-[SiMo2W10O40]n- (n= 4 or 6)

The tetrabutylammonium gamma-dodecatungstosilicate has been crystallized in a 6/1 acetonitrile/water solvent. An X-ray single-crystal analysis was carried out on [N(C4H9)4]4-gamma-[SiW12O40] which crystallizes in the orthorhombic system, space group P2(1)2(1)2(1), with a = 19.0881(3) A, b = 21.4435(3) A, c = 26.0799(1) A, V = 10674.9(2) A3, Z = 4, and rho(calcd) = 2.392 g/cm3. The idealized C2v arrangement of the anion results from the rotation of 60 degrees of two trigonal [W3O13] groups in the Keggin anion. Taking as reference the geometrical characteristics of the Keggin anion, it appears that the bond lengths and bonds angles within the four [W3O13] groups are not significantly modified while the mu-oxo junctions between the two rotated groups and those between the two unrotated groups involve more acute and opened W-O-W angles, respectively. The syntheses and 183W NMR characterizations of the mixed gamma-[SiW10Mo2O40]n- compounds corresponding to the oxidized (Mo(VI); n = 4) and to the two electron-reduced (Mo(V); n = 6) anions are reported. Structural analysis by 183W NMR has proved unambiguously that the C2v structure of the gamma-[SiW10O36]8- subunit is retained in both the compounds. The electronic behavior of the series gamma-[SiW10M2E2O36]6- (M = Mo or W; E = O or S) is examined, compared and related to 183W NMR data.     

新型层状异金属配位聚合物{[(CuL)2Sr(H2O)·Sr2(H2O)7]·2H2O·0.5CH3OH}n的合成、表征及晶体结构

合成了铜锶异金属配位聚合物, 并通过元素分析和IR光谱对其进行了表征, 利用X射线单晶衍射测定了其晶体结构. 该化合物为具有{[(CuL)2Sr(H2O)·Sr2(H2O)7]·2H2O·0.5CH3OH}n化学组成的二维层状配位聚合物[H4L=N-(3-羧基水杨醛)-N'-(2-羟基苯甲酰基)乙撑二胺], 其结构单元由两个相邻的片段组成, 这些结构单元彼此相互配位, 从而形成了一种结构新颖的层状配位聚合物.