钨酸催化氧化环己烯合成己二酸

以钨酸/有机酸性添加剂为催化体系, 在无有机溶剂、相转移剂的情况下, 催化30%过氧化氢氧化环己烯合成己二酸. 当钨酸∶有机酸性添加剂∶环己烯∶过氧化氢＝1∶1∶40∶176(摩尔比, 钨酸用量为2.5 mmol)时, 使用有机酸性添加剂考察钨酸的催化性能, 结果表明以钨酸/间苯二酚催化氧化环己烯的催化效果最优, 反应8 h时己二酸分离产率达90.9%、纯度为～100%; 而不使用有机酸性添加剂时, 己二酸分离产率只有72.1%, 产品纯度为96.2%. 当使用磺酸水杨酸、草酸、水杨酸为有机酸性添加剂时, 随反应时间的增加, 己二酸分离产率均升高, 但反应6 h以后, 己二酸分离产率随时间的变化不明显. 当磺酸水杨酸用量为2.5 mmol时, 己二酸分离产率和纯度均较高. 钨酸-磺酸水杨酸催化体系重复使用五次后, 己二酸分离产率仍可达到80.5%.     

杂多酸型离子液体催化莰烯直接水合反应的研究

合成了6种杂多酸型离子液体,用于催化莰烯直接水合制异龙脑,考察了催化剂的种类及用量、反应温度、反应物配比和反应时间等因素对反应的影响.实验结果表明,1-(4-磺酸基)丁基-3-甲基咪唑硅钨酸盐([BSmim]_4SiW_(12)O_(40))催化剂的活性优于传统的催化剂;合成异龙脑的适宜条件为:温度80℃,[BSmim]_4SiW_(12)O_(40)催化剂用量为反应物总质量的20%,莰烯∶水∶异丙醇=1∶1∶2(质量比),反应时间3 h,在此条件下莰烯的转化率为23.55%,异龙脑的选择性为87.77%;[BSmim]_4SiW_(12)O_(40)催化剂重复使用5次,其催化活性无明显下降.     

新型异核双阳离子型磺酸功能化离子液体的合成及其催化活性

合成了三种基于1-吗啉基-3-咪唑基丙烷异核双阳离子的新型二磺酸功能化BrΦsted酸性离子液体:1-[4-(4-磺酸丁基)吗啉基-3-[3-(4-磺酸丁基)咪唑基]丙烷二(三氟甲烷磺酸)盐{A,[(C4SO3H)m(C4SO3H)i]p(OTf)2}、1-[4-(4-磺酸丁基)吗啉基-3-[3-(4-磺酸丁基)咪唑基]丙烷二硫酸氢盐{B,[(C4SO3H)m(C4SO3H)i]p(HSO4)2}及1-[4-(4-磺酸丁基)吗啉基-3-[3-(4-磺酸丁基)咪唑基]丙烷二磷酸二氢盐{C,[(C4SO3H)m(C4SO3H)i]p(H2PO4)2}.其结构经FT-IR、MS、NMR等确认.选择吗啉、甲基咪唑单磺酸功能化离子液体作为对照组,以苯甲醛与环己酮之间的交叉Aldol缩合反应考察了其催化活性.用Hammett方法测定了其酸性,实验结果表明,所合成的三种双磺酸功能化离子液体的催化能力比单磺酸功能化离子液体的强,其酸性次序与催化活性相一致.其中,阴离子为三氟甲烷磺酸根的离子液体对18种Aldol缩合反应底物有极好的适应性,并且催化活性最强,产率高达90%,在重复使用10次后,仍保持较高的反应活性.关键词二磺酸功能化离子液体;合成;催化活性;Hammett方法;交叉Aldol缩合反应;重复使用     

2-取代-4(3H)-喹唑啉酮在Br(o)nsted酸性功能化离子液体中的微波合成

以N-甲基咪唑、吡啶为起始原料,合成了二种新型Br(o)nsted酸性功能化离子液体:1-(4-磺酸基)苄基-3-甲基咪唑硫酸氢根盐(3a),N-(4-磺酸基)苄基吡啶硫酸氢根盐(3b),以其作为反应介质与催化剂,研究了2-取代-4(3H)-喹唑啉酮的三组分、一锅法微波合成.结果表明,当n(2-氨基苯甲酸):n(酰氯):n(乙酸铵):n(3a或3b)=1:1.2:1.5:0.1时,反应6 min即可完成,产率81%～95%.离子液体经减压蒸馏、真空干燥可重复使用3次,催化活性基本保持不变.     

2-取代-4(3H)-喹唑啉酮在BrФnsted酸性功能化离子液体中的微波合成

以N-甲基咪唑、吡啶为起始原料,合成了二种新型BrФnsted酸性功能化离子液体:1-(4-磺酸基)苄基-3-甲基咪唑硫酸氢根盐(3a),N-(4-磺酸基)苄基吡啶硫酸氢根盐(3b),以其作为反应介质与催化剂,研究了2-取代-4(3H)-喹唑啉酮的三组分、一锅法微波合成.结果表明,当n(2-氨基苯甲酸):n(酰氯):n(乙酸铵):n(3a或3b)=1:1.2:1.5:0.1时,反应6min即可完成,产率81%～95%.离子液体经减压蒸馏、真空干燥可重复使用3次,催化活性基本保持不变.     

新型功能化Brφsted酸性离子液体1,4-二(4-磺酸基丁基)哌嗪硫酸氢盐磺酸的合成及其对酮醛交叉Aldol缩合反应的催化作用

以哌嗪和1,4-丁基磺酸内酯为原料合成了新型功能化Brφsted酸性离子液体——1,4-二(4-磺酸基丁基)哌嗪硫酸氢盐磺酸{[(HSO3-b)2pi]2+·2[HSO4]-)SO3H(Ⅱ)},其结构经1H NMR和IR表征。在无溶剂(或无水乙醇)条件下,以Ⅱ催化环己酮与取代苯甲醛的交叉Aldol缩合反应,成功地合成了十个α,α’-二(苯基亚甲基)环己酮类化合物(3a～3j),收率77.5%～85.7%,其结构经1H NMR,13C NMR和IR表征,其中3e～3i为新化合物。     

(5-氨基-[1,3,4]噻二唑-2-基)-丙酸乙酯的合成工艺改进

以丁二酸酐为起始原料,经醇解和酰化反应制得丁二酸单乙酯酰氯(3);3经甲烷磺酸催化与氨基硫脲环合合成了重要药物中间体——(5-氨基-[1,3,4]噻二唑-2-基)-丙酸乙酯,其结构经~1H NMR,IR和MS确证。运用正交试验对环合反应条件进行优化。最优反应条件为:3 132 mmol,n(氨基硫脲)∶n(3)∶n(甲烷磺酸)=1∶3∶3,于110℃反应3 h,总收率51.3%。     

有机-无机杂化钨(钼)过氧配合物催化合成己二酸

以1,10-菲啰啉(Phen)作N,N配体制备了双核同多钨(钼)杂化过氧配合物H2M2O3(O2)4.2Phen(M:W、Mo),为己二酸的绿色合成提供了一类双功能催化剂。通过元素分析、重量法、化学滴定法、TG/DSC、IR和UV-Vis测试技术对其组成和结构进行了表征。在不使用有机溶剂和相转移催化剂的条件下,考察了它们催化30%的H2O2氧化环己烯、环己醇和环己酮合成己二酸的催化活性。实验结果表明,钨过氧配合物的催化活性较好,钼过氧配合物的催化活性差;以H2W2O3(O2)4.2Phen.H2O作催化剂,反应条件为n(底物)∶n(催化剂)∶n(H2O2)=100∶1.2∶440,反应温度为90℃,反应12 h,从环己烯、环己醇和环己酮到己二酸的收率分别为89.9%、53.5%和64.8%。     

聚合离子液体磷钨酸盐合成及催化模拟油氧化脱硫

合成了新型的聚合离子液体磷钨酸盐(聚1-丁基-3-乙烯基咪唑磷钨酸盐)(PBVIm PW),采用FT-IR、XRD和TG进行表征,通过CHN元素和ICP分析确定其结构。催化剂用于过氧化氢为氧化剂的模拟油品氧化脱硫反应。考察反应温度、氧硫比、催化剂用量等对脱硫率的影响。结果表明,当反应温度为50℃,n(H_2O_2)/n(S)为8,n(PBVIm PW(P))/n(BT)为0.4∶1.0,反应时间150 min时,苯并噻吩(BT)的转化率可以达到99.4%。催化剂可回收重复使用四次,催化活性无明显下降。     

2,5-二甲氧基-4-[(1E)-2-(1H-苯并咪唑-2-基)乙烯基]苯甲醛的合成

以2-甲基苯并咪唑(1)和2,5-二甲氧基-1,4-对苯二甲醛(3)为原料,经缩合反应合成了新化合物——2,5-二甲氧基-4-[(1E) -2-( 1H-苯并咪唑-2-基)乙烯基]苯甲醛(4),其结构经1H NMR,IR和ESI-MS表征.较佳缩合反应条件为:1 11 mol,n(1)∶n(3)=1.1∶1.0,回流反应6h,收率75.2％.     

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.     

Construction of polyoxometalates-based coordination polymers through direct incorporation between polyoxometalates and the voids in a 2D network

A series of polyoxometalates (POMs)-based coordination polymers, namely, {[Cu(2,3-Me2pz)(2,5-Me2pz)0.5]4(SiW12O40)(2,5-Me2pz)}n (2,3-Me2pz = 2,3-dimethylpyrazine; 2,5-Me2pz = 2,5-dimethylpyrazine; 1), {[Cu2(4,4'-bipy)4(H2O)4](SiW12O40)(H2O)18}n (4,4'-bipy = 4,4'-bipyridine; 2), {[Cu(2-Mepz)1.5]3(PMo12O40)(H2O)3.5}n (2-Mepz = 2-methylpyrazine; 3), {[Ag(2,3-Me2pz)1.5]4(SiW12O40}n (4), {[Cu(pz)1.5]4(SiW12O40)(H2O)3}n (pz = pyrazine; 5), {[Cu(2,3-Me2pz)1.5]4(SiW12O40)}n (6), {[Cu(4,4'-bipy)1.75]4(SiW12O40)(H2O)2}n (7), and {[Cu2(4,4'-bipy)4(H2O)4](SiW12O40)(4,4'-bipy)2(H2O)4}n (8), were synthesized through direct incorporation between POMs and the voids of the 2D network. Crystal structural analysis reveals that the relationship between the size of the void of the 2D network and that of POMs is of key importance for successful synthesis of POMs-based open metal-organic frameworks. Guest replacement shows that the pore size of the framework constructed through direct incorporation between POMs and the voids of the 2D network is very sensitive to guest molecules.     

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。     

pH-Controlled assembly of two POM-based inorganic–organic hybrid copper coordination polymers: synthesis,structures and properties

Transition Metal Chemistry - Two POM-based copper coordination polymers constituted by Keggin-type polyoxometalates (POMs), [Cu2 (SiW12O40)2 (Fbtx)3 (H2O)4]n (1) and {[Cu2 (SiW12O40) (Fbtx)2...     

含混合配体多酸超分子化合物的水热合成、晶体结构及催化活性

在水热条件下合成了四个含混合配体4,4’-bipy和2,2’-bipy/phen的多酸配位聚合物[Cu(4,4’-bipy)(2,2’-bipy)2]2[SiW12O40]?4H2O (1),[Ag4(4,4’-bipy)3(2,2’-bipy)2][SiW12O40]?2H2O (2),[Cu(4,4’-bipy)(phen)]2[H3O]2[SiW12O40]?8H2O (3)和[Cu(4,4’-bipy-Cl)(phen)]2[H3O][PW12O40]?H2O (4) (bipy = 联吡啶,phen = 邻菲罗啉),通过红外光谱、热重、元素分析、X-单晶衍射对聚合物进行了表征,在苯乙烯催化环氧化反应中,3和4显示了较高的催化活性,这与结构中存在配位不饱和金属中心有关.     

Selective precipitation of prions by polyoxometalate complexes

The efficacy of a variety of polyoxometalate anions in selectively precipitating the infectious isoform of the prion protein (PrPSc) over the normal, cellular protein (PrPC) was tested as a means of improving the sensitivity of a conformation-dependent immunoassay (CDI). Experiments utilizing neutralized aqueous solutions containing MgCl2.6H2O and Na2H[PW12O40] (1) indicated that use of the former is detrimental to selectivity, while use of the latter gives optimal selectivity at a concentration of 2.48% w/v, much higher than the 0.31% w/v employed in the current CDI protocol. Similar experiments using Na4[SiW12O40] (2), K5[BW12O40] (3), and Na6[H2W12O40] (4) were performed to probe the role of charge density in polyoxometalate anions possessing the Keggin structure. These, coupled with assignment of solution structures via NMR and infrared spectroscopy, revealed the following trend in optimal concentrations: [HBW11O39]8- < [SiW11O39]8- < [PW11O39]7- = [H2W12O40]6-. Interestingly, use of the salts K10[Zn4(H2O)2(PW9O34)2] (5), Na16[Zn4(H2O)2(P2W15O56)2] (6), and Na27[NaAs4W40O140] (7), containing larger polyoxometalate anions, was found to suppress PrPSc precipitation in a concentration-dependent manner. Taken together, the results suggest a precipitation mechanism wherein Keggin-type anions link multiple PrPSc moieties by binding a somewhat hindered cleft featuring one or more positively charged residues.     

钨酸催化氧化环己烯合成己二酸

以钨酸为催化剂,过氧化氢为氧化剂,催化氧化环己烯(1)合成了己二酸（2）,其结构经¹H NMR和IR确证。采用正交实验法研究了过氧化氢浓度、钨酸用量和磷酸用量对2收率的影响。采用单因素法考察了酸性助剂,过氧化氢用量及其加料方式对收率的影响。结果表明：在最佳反应条件［n(H₂O₂)：n(1)：n(钨酸)=4.6 ：1.0：0.06, w(H₂O₂)=27.5%,回流反应1.7 h］下,2收率95.1%,纯度99.2%。     

Mechanistic analysis of the electrocatalytic properties of dissolved alpha and beta isomers of [SiW12O40]4- and solid [Ru(bipy)3]2[alpha-SiW12O40] on the reduction of nitrite in acidic aqueous media

Voltammetric studies on the reduction of alpha and beta isomers of the Keggin polyoxometalate anion [SiW12O40]4- reveal a series of electrochemically reversible processes in acidic aqueous media. In the presence of NO2-, catalytic current is detected in the potential region of the [SiW12O40]4-/5- process. Electronic spectroscopy and simulation of voltammetric data undertaken at variable [NO2-] and [H+] allow the following mechanism to be postulated, [SiW12O40]4- + e- <-->[SiW12O40]5-, H+ + HNO2 <--> NO+ + H2O, NO+ + [SiW12O40]5- --> NO + [SiW12O40]4-. The second-order rate constant for the rate-determining step is faster for the alpha isomer than for the beta one. This may be attributed to the different reversible potentials of -0.144 V (alpha isomer) and -0.036 V vs Ag/AgCl (beta isomer) and, hence, smaller driving force for an assumed outer sphere electron-transfer reaction in the case of beta isomer. A stable, water-insoluble, thin-film [Ru(bipy)3]2[alpha-SiW12O40] chemically modified electrode was generated electrochemically via ion-exchange of [Ru(bipy)3]2+ with Bu4N+ in the [Bu4N]4[alpha-SiW12O40] solid. The first reduction process with this modified electrode gives rise to the reaction [Ru(bipy)3]2[alpha-SiW12O40](solid) + H+(soln) + e- <--> H[Ru(bipy)3]2[alpha-SiW12O40](solid). The need to transfer a proton from the solution to the solid phase for charge neutralization purposes introduces a hydrogen-ion concentration dependence into this reaction, which is not found in the solution-phase study. Nevertheless, the voltammetric catalytic activity with respect to nitrite reduction is retained with the chemically modified electrode. However, nitrite catalysis with the [Ru(bipy)3]2[alpha-SiW12O40]-modified electrode is now independent of concentration of H+, rather than exhibiting a first-order dependence, and full mechanistic details for this process are unknown.     

Inorganic-organic hybrid materials with different dimensions constructed from copper-fluconazole metal-organic units and Keggin polyanion clusters

Inorganic-organic hybrid materials based on Keggin polyoxometalate building blocks combined with Cu(II)/Cu(I) and flexible fluconazole ligand [1-(2,4-difluorophenyl)-1,1-bis[(1H-1,2,4-triazol-1-yl)methyl]methanol] (Hfcz) have been obtained by hydrothermal methods, namely, [Cu(II)(2)(Hfcz)(4)(SiW(12)O(40))].3H(2)O (1), [Cu(II)(4)(fcz)(4)(H(2)O)(4)(SiMo(12)O(40))].6H(2)O (2), [Cu(II)(2)(fcz)(2)][Cu(II)(4)(fcz)(4)(SiW(12)O(40))][Cu(II)(2)(fcz)(2)(H(2)O)(2)(SiW(12)O(40))].6H(2)O (3), (Et(3)NH)(2)[Cu(I)(2)(Hfcz)(2)(SiW(12)O(40))].2H(2)O (4), (Et(3)NH)(2)[Cu(I)(2)(Hfcz)(2)(SiW(12)O(40))].H(2)O (5) and [Cu(I)(4)(Hfcz)(4)(SiMo(12)O(40))] (6). Their structures have been determined by single-crystal X-ray diffraction analyses, and the compounds are further characterized by elemental analyses, IR spectra and thermogravimetric (TG) analyses. In 1, Cu(II) cations are bridged by fluconazole ligands to form a 3D lvt coordination polymeric network, which is connected by (SiW(12)O(40))(4-) anions to form a complicated 3D (4,6)-connected framework with the topology of (4(2).6(4))(4(6).6(7).8(2))(2). In 2, two fcz(-) anions chelate two Cu(2+) cations to form a [Cu(fcz)](2)(2+) dimer, which is bridged by (SiW(12)O(40))(4-) polyanions to generate a 2D (4,4) grid. Compound 3 is formed by three types of co-crystallizing subunits including a dimer [Cu(fcz)](2)(2+), a dumbbell molecule [Cu(4)(fcz)(4)(SiW(12)O(40))] and an infinite chain {[Cu(2)(fcz)(2)(H(2)O)(2)(SiW(12)O(40))](2-)}(infinity). In compounds 4 and 5, Hfcz ligands link Cu(+) cations to generate 1D coordination polymeric units, and (SiW(12)O(40))(4-) polyanions connect these metal-organic units to form two types of (6(3)) sheets which are topological isomerism. In compound 6, (SiMo(12)O(40))(4-) polyanions fixed in Cu(I)-Hfcz square rings are further extended into a 2D sheet via linking Cu(I) atoms of different rings. By carefully inspection of the structures of 1-6, it is believed that various transition-metal organic units and Keggin polyanions with different coordination modes are important for the formation of the different structures. In addition, electrochemical behaviors of compounds 1, 2, 5 and 6 have been investigated.     

Hydrothermal Synthesis and Crystal Structure of a Polyoxometalate- based Complex [Cu^I（phen）2]4（SiW12O40）

A new hybrid polyoxometalate-based complex, [Cu^I（phen）214（SiW12O40） （phen = 1,10-phenanthroline）, has been synthesized by hydrothermal method and characterized with the aid of elemental analysis, IR, UV spectra and thermal analysis studies. The result of X-ray crystallography analysis exhibits that the title compound crystallizes in the orthorhombic space group P212121, and the formula is C96H64N16Cu4SiW12O40. Crystal data： a = 18.3574（14）, b = 21.1952（16）, c = 27.992（2）A, Mr = 4570.08, V = 10891.4（14）A^3, Z = 4, Dc = 2.787 g/cm^3,μ = 13.478 mm^-1, R = 0.0364, wR = 0.0638 （I 〉 2σ（I）） and F（000） = 8360. The complex consists of one α-Keggin anion [SIW12O40]^4- and four discrete [Cu^I（phen）2]^＋ cations. The valence sum calculations for the Cu atoms suggest that all four Cu atoms are in the ＋1 oxidation state.