钒取代多金属氧酸盐/聚酰胺-胺多层膜的制备及其电催化性能

用层接层自组装的方法制备了过渡金属钒取代的多金属氧酸盐PMo11VO4-40/聚酰胺-胺多层纳米复合膜. X射线光电子能谱(XPS)、紫外-可见光谱(UV-Vis)、循环伏安(CV)测定和分析结果表明, PMo11VO4-40和聚酰胺-胺通过静电相互作用形成了纳米交替多层膜,且膜的增长均匀. 复合膜的循环伏安图呈现出四对氧化还原峰(一个V的单电子和三个Mo的双电子), 峰电流与扫描速率成正比, 其式量电位随着pH 的增加而线性负移, 表明电极过程属于表面控制过程, 电荷传递很快且有氢离子参与多金属氧酸盐的氧化还原反应. 该方法制备的多层膜修饰电极稳定性好, 对NO-2、BrO-3及H2O2具有良好的催化还原活性.     

超氧化物歧化酶在纳米金/L-半胱氨酸修饰金电极上的电化学行为

通过L-半胱氨酸将纳米金修饰到金电极上,把超氧化物歧化酶(SOD)固定在修饰电极表面,制备了SOD-纳米金/L-半胱氨酸修饰电极。运用交流阻抗法、循环伏安法等方法表征了该电极,发现SOD在该电极上于0.15V和-0.05V左右产生较明显的氧化还原峰,在0.04～0.24V/s扫描速率范围内,其还原峰电流与扫描速速呈线性关系,表明该电极过程受吸附控制。研究了H2O2对SOD-纳米金/L-半胱氨酸修饰电极伏安行为的影响,发现该电极的还原峰电流与H2O2浓度在1.0×10-6～2.0×10-4mol/L范围内呈良好的线性关系,相关系数为-0.996,可用于对H2O2的分析检测。     

钼钒磷酸四乙胺纳米粒子体修饰碳糊电极及其对过氧化氢的电催化还原

首次研究了无机 有机杂化的钼钒磷酸基的多金属氧酸盐纳米粒子 [(C2 H5) 4N]4PMo1 1 VO40 ·H2 O体修饰碳糊电极在 0 .5mol LH2 SO4+0 .1mol LNa2 SO4溶液中的电化学行为 ,结果表明该修饰电极对H2 O2 的电化学还原表现出很好的催化作用 ,而且具有优良的稳定性 ,这主要归因于该多金属氧酸盐纳米粒子的难溶性及其在石墨表面的强吸附。该修饰电极最独特的优点是电极表面可以重复更新。     

纳米TiO2修饰碳糊电极伏安法测量痕量铟

采用溶胶-凝胶法制备了纳米TiO2粉末,成功地将其修饰在碳糊电极上,用阳极溶出伏安法考察了修饰电极测量痕量铟的优化条件及其电化学稳定性.结果表明,在pH=5.4的Hac-NaAc缓冲液中,当In3 在纳米TiO2修饰碳糊电极表面富集时间为200s,电位扫描速率控制为200mV/s时,修饰电极在伏安图上能出现1个灵敏的氧化峰,峰电位为-0.832V,利用该峰可以进行痕量铟的检测;峰电流与In3 浓度在1.0×10-11～1.0×10-9mol/L的范围内成良好线关系,相关系数为0.995,检出限为0.125×10-11mol/L;修饰电极稳定性较好,用于实际水样中钢含量的测定,平均回收率为96.16%,结果令人满意.同时循环伏安和交流阻抗实验表明,铟在修饰电极上电化学氧化为不可逆过程,受电荷传质和扩散过程混合控制;该电极过程的平均活化能为72.36kJ/mol.     

流动注射掺杂普鲁士蓝碳糊电极测定过氧化氢

在化学法制得普鲁士蓝(PB)粉末的基础上,用固体石蜡作粘合剂,将PB粉末和石墨粉按一定比例充分混合,制得掺杂PB的碳糊电极(PBCPE)。研究了该修饰电极的制备,电化学性质及对H2O2的电催化作用。该修饰电极在0.5mol/L的KCl底液中进行循环伏安实验,于0.2V(vs.SCE)附近出现一对氧化还原峰,扫速为30mV/s时,峰电位差67mV,重现性良好。采用流动注射进样,基于PBCPE电极成功实现了恒电位快速检测医用消毒水中H2O2的浓度。最佳检测电位为-0.3V,进样频率为120次/小时。响应电流与H2O2的浓度在0.08～3.2mmol/L范围内呈良好的线性关系,线性相关系数为0.9994,检出限为2.4×10-6mol/L(S/N=3)。     

铜配合物修饰的钼氧簇超分子化合物催化烯烃环氧化

近年来,含有过渡金属配合物和多金属氧酸盐的三维超分子化合物的合成与性能研究受到广泛关注.利用过渡金属配合物优良的可裁剪性和修饰性,可以对多金属氧酸盐化合物的结构和性质进行有效调控,进而构造出具有独特空间结构和性质的新型功能材料.这类材料往往具有多金属氧酸盐与过渡金属配合物两者结合的优点,在医学、光学、磁性材料、气体吸附材料及催化等领域显示出重要的学术研究价值和潜在的应用前景.然而,相比于在化合物合成及结构研究领域中的快速发展,过渡金属配合物修饰的多金属氧酸盐基化合物在催化领域中应用较少.本文采用水热合成法,以4,4′-联吡啶(bipy)或1,4′-双咪唑-1-甲基苯(bix)为氮杂环配体,合成了两个铜配合物修饰的钼氧簇超分子化合物催化剂,分别记为[Cu(bipy)]4[Mo15O47]·2H2O (1)和[Cu(bix)][(Cubix)(δ-Mo8O26)0.5](2).催化剂1中包含一个由铜的4,4′-联吡啶有机链修饰的钼氧簇链,催化剂2是由1,4′-双咪唑-1-甲基苯有机配体、铜离子和八钼酸盐构筑的具有自穿插结构的超分子化合物.通过以叔丁基过氧化氢为氧化剂的烯烃环氧化催化反应,考察了两种催化剂的催化性能.结果表明,催化剂1和2对环辛烯或1-辛烯环氧化反应表现出较高的催化活性,性能均明显优于未引入铜配合物的超分子化合物(H2bix)[(Hbix)2(γ-Mo8O26)]2·H2O (3);在相同反应条件下,催化剂1表现出更高的催化活性;溶剂种类显著影响催化剂的催化性能,以乙腈为溶剂时,苯乙烯环氧化反应主产物为苯甲醛(仅有很少量的环氧化合物),而以氯仿为溶剂时,环氧化合物选择性显著提高;中断实验和循环测试结果表明,催化剂1和2在1-辛烯环氧化反应中均表现出良好的稳定性和循环使用性. FT-IR和XRD表征结果证实,经多次循环使用后催化剂结构基本保持不变,表明催化剂具有良好的结构稳定性. XPS表征结果表明,催化剂1中钼的正电性高于催化剂2,这是由于配体类型不同及钼氧簇结构不同所致.拥有较高正电性的钼物种通常会表现出更高的催化烯烃环氧化反应能力,这可能是催化剂1的催化活性优于催化剂2的主要原因.此外,通过结构分析可以看出,催化剂1具有更开放的框架结构,这更有利于反应物扩散,继而使催化剂表现出更高的催化活性.需要指出的是,催化剂1和2中存在的铜配合物也可能直接作为新的活性中心参与对氧化剂的活化,继而对催化剂性能(活性和选择性)产生影响;此外,铜配合物与钼氧簇之间较强的相互作用使所形成的超分子化合物具有良好的结构稳定性,继而使这类超分子化合物催化剂表现出较为优异的稳定性和循环使用性.     

聚苯胺/钴-氧化钴膜作传感元件的pH传感器的性能

研究了在玻碳电极上修饰不同物质所制得的pH传感器,通过电位滴定的方法比较得出先修饰聚苯胺,再修饰钴-氧化钴膜的电极对pH有较好的响应,能代替玻璃电极应用在实际样品测定中. 探究了最佳修饰条件为:先在0.1 mol/L苯胺的盐酸(1 mol/L)溶液中, 电位范围为-0.2～1.0 V,以100 mV/s 的扫描速率循环伏安扫描10圈修饰聚苯胺膜;接着在含2.0×10-4 mol/L Co2+的磷酸盐缓冲溶液(PBS)(pH=7.5)中,电位范围为-1.2～1.2 V,以100 mV/s的扫描速率循环伏安扫描 5圈修饰钴-氧化钴膜. 得到的修饰电极响应斜率为-61.60 mV/pH,响应范围pH值为0.5～13.     

新型无机-有机超分子化合物{(HINO)6·(P2W18O62)·14H2O}的合成、结构及性质

以Wells-Dawson型多金属氧酸盐[P2W18O62]6-和4-吡啶甲酸(HINO)为混合配体,采用水热技术合成了一种新的无机-有机三维超分子化合物{(HINO)6(P2W18O62)·14H2O},并通过元素分析、红外光谱、热重分析和X射线单晶衍射等方法对其进行了表征.结果表明,该化合物属于单斜晶系,P21/c...     

细胞色素C在4,5-二氮芴-9-酮修饰玻碳电极上的直接电化学研究

采用循环伏安法探讨了细胞色素C(Cyt C)在4, 5-二氮芴-9-酮(dafo)修饰玻碳电极表面的电化学行为.结果表明,Cyt C在dafo修饰电极上呈现一对峰形较好且准可逆的氧化还原峰,其式电位(E0′)为13 mV,峰电流与扫描速度呈线性关系,该电极过程是表面控制过程,电化学反应效率常数(ks)为0.89/s.固定在dafo上的Cyt C能促进H2O2的催化还原,响应快速而灵敏(<10 s),峰电流与H2O2浓度在5.0×10-6～3.0×10-4 mol/L范围内呈线性关系;检出限2.5×10-6 mol/L;米氏常数为1.07 mmol/L,显示出较好的亲和力.     

[Co（bim）x]配合物修饰的｛P2Mo5O23｝超分子的合成、晶体结构和电化学性质

利用水热技术合成了一种新型[Co(bim)x]配合物修饰的磷钼多金属氧酸盐超分子化合物[Co(bim)3] [Co(Hbim)2( H2 O) P2 Mo5 O23]·5H2O.通过元素分析、红外光谱、热重分析和X射线单晶衍射对化合物进行了表征.化合物属于单斜晶系,P2(1)空间群;晶胞参数:a=11.505 (2) nm,b=19.123 (3) nm,c=13.852(2) nm,α=90.00°,β=100.073(2)°,γ=90.00°,V=3 000.6(8)nm3,F(000)=1 756.0,Z=2.并测试了合成化合物的电化学性质.     

A novel inorganic–organic hybrid compound constructed from copper(II)-monosubstituted polyoxometalates and poly(amidoamine)

A novel inorganic–organic hybrid compound constructed from copper(II)-monosubstituted polyoxometalate Na₅PW₁₁Cu(H₂O)O₃₉ (PW₁₁Cu) and poly(amidoamine) (PAMAM) dendrimer was prepared at room temperature in an aqueous solution. The title compound PW₁₁Cu/PAMAM was characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction, indicating that the PW₁₁Cu was chemically anchored to PAMAM. The compound was first used as a bulk-modifier to fabricate a chemically modified carbon paste electrode (CPE) by direct mixing. The PW₁₁Cu/PAMAM bulk-modified CPE showed well-defined cyclic voltammograms with four redox couples in 0.2 M NaAc buffer solution and high electrocatalytic activity for the reduction of hydrogen peroxide and nitrite. Furthermore, the CPE revealed good stability due to the insolubility of the title compound and the interaction between PW₁₁Cu and PAMAM.     

铁氰化镧修饰电极的制备及表征

An electroactive polynuclear inorganic compound of rare earth metal hexacyanoferrate, lanthanum hexacyanoferrate (LaHCF), was prepared by electrochemical deposition on the surface of a glassy carbon electrode with a potential cycling procedure. The cyclic voltammogram of LaHCF exhibits a pair of well-defined redox peaks with the formal potential of 208 mV (vs. SCE) at a scan rate of 100 mV/s in 0.2 mol/L NaCl solution and the redox peak currents increase linearly with the square root of the scan rate up to 1000 mV/s. The effects of the concentration of supporting electrolyte on the electrochemical characteristics of LaHCF were studied by voltammetry. LaHCF was also characterizated by scanning electron microscope (SEM), FTIR and XPS techniques.     

Syntheses, Crystal Structures and Electrochemical Properties of Two Molybdophosphates

Two molybdophosphate compounds,[Ni(bim)3]2[H2P2Mo5O23]·2H2O 1 and [Zn(bpy)2]2[Zn(bpy)(H2O)]2Zn[Mo6O12(OH)3(HPO4)4]2·9H2O 2 (bim = 2,2'-biimidazole,bpy = 2,2'-dipyridyl),have been synthesized under hydrothermal conditions and structurally characterized by elemental analysis,TG,and IR. The single-crystal X-ray analysis exhibits that 1 consists of one [H2P2Mo5O23]4-,two [Ni(bim)3]2+ cations and two lattice water molecules,while 2 is constructed from one sandwich-type [ZnP4Mo6] anion modified by four Zn-bpy complexes and nine lattice water molecules. The electrochemical behaviors of compounds 1 and 2 have been studied in detail based on solid bulk modified carbon paste electrodes of compound (CPEs).     

STUDY OF REDOX PROPERTIES OF TETRANUCLEAR DENUM CLUSTER COMPOUND {Mo_4(μ_3-S)(μ_3-O)[S_2P(OEt)_2]_6}

<正> The redox properties of tetranuclear molybdenum cluster {Mo4(μ3-S)3(μ3-O)CS2P(OEt)2D6}(1)have been investigated by linear sweep voltammetry,cyclic voltammetry,differential pulse voltammetry and controlled potential coulome-try.It is showed that the compound undergoes two consecutive near reversible one-electron reductions at-0.03V and-0.79V respectively and a near reverisble one-electron oxidation at 0.98V with scan rates from 25 mV/sec to 1V/sec in cyclic voltammetric measurements.Three stable peaks can still be seen after several hours of repeated slow speed scan(1mV/sec)in differential pulse voltammetry.These evidences suggest the high structural stability of this cluster compound.     

Electrochemical preparation and characterization of dysprosium hexacyanoferrate modified electrode

An electroactive polynuclear inorganic compound of rare earth metal hexacyanoferrate, dysprosium hexacyanoferrate (DyHCF), was prepared by a procedure of electrochemical deposition on the surface of a glassy carbon electrode with a potential cycling procedure. The cyclic voltammogram of DyHCF exhibits two pairs of redox peaks with the formal potential of +210 and +362 mV (vs. SCE), respectively, at a scan rate of 10 mV/s in 0.2 mol/L KCl solution. The different electrochemical behaviors of DyHCF in various cation-containing supporting electrolytes were investigated by cyclic voltammetry. DyHCF was also characterized by scanning electron microscope (SEM), FTIR , XPS etc. techniques.     

Direct Electrochemistry of Hemoglobin Immobilized in Sodium Alginate Film on the Ionic Liquid [BMIM]PF6 Modified Carbon Paste Electrode

In recent years the direct electron transfer of redox protein on electrode surface has attracted great attentions1. Different kind of modified electrode and various supporting films for immobilization of proteins had been proposed. But most of them are ba…     

Synthesis,Crystal Structure of Cis—dioxo—catecholatotungsten（VI） Complex and Its NMR Studies on the Interaction with ATP

Cis-dioxo-catecholatotungsten(VI) complex anion[W^(VI)O2-(OC6H4O)2]^2- was obtained with discrete protonated ethylenediamine (NH2CH2CH2NH3)^ cations by the reaction of tetrabutyl ammonium decatungstate with catechol in the mixed solvent of CH3OH,CH3CN and ethylenediamine,and compared with its molybdenum anaogue [Mo^(V) O2(OC6H4O)2]^3- by crystal structure,UV,EPR,The results of the UV and EPR spectra show that tungsten is less redox active than molybdenum since the molybdenum is reduced from Mo(VI) to Mo(V) but tungsten stays in the original highest oxidized state Mo(VI) when they are crystallized from the solution above.It is worthy to note that [W^(VI)O2(OC6H4O)]^2- shows the same coordination structure as its molybdenum analogue in which the metal center exhibits distorted octahedral coordination geometry with two cis-dioxocatecholate ligands and might have the related coordination structure feature with the cofactor of flavoenzyme because [Mo^(V)O2(OC6H4O)2]^3- presented essentially the same EPR spectra as flavoenzyme.The NMR studies on the interaction of the title complex with ATP reveal that the reduction of W(VI) to W(V) occurs when the title complex is dissolved in D2O and the W(V) is oxidized again when ATP solution is mixed with original solution and the hydrolysis of the catecholato ligand take places at mean time being monitored by ^1H NMR and ^13C NMR spectra.     

一个镉配位聚合物[Cd(Pyphen)(1，4-BDC)(H2O)]·0.5Pyphen的合成、结构和荧光性质研究

The title complex, [Cd(Pyphen)(1,4-BDC)(H₂O)]·0.5Pyphen (1) (Pyphen=pyrazino[2,3-f][1,10]phenanthr-oline and 1,4-H₂BDc=1,4-benzenedicarboxylic acid) has been obtained by using hydrothermal synthesis and characterized by elemental analysis, IR, fluorescence spectrum and single-crystal X-ray diffraction. It crystallizes in orthorhombic, space group Pbcn with a=2.489 2(5) nm, b=0.967 88(19) nm, c=2.057 0(4) nm, V=4.955 9(17) nm³, Z=8, CdC₂₉H₁₈N₆O₄, M_r=642.89, D_c=1.723 g·cm^-3, F(000)=2 576, μ(Mo Kα)=0.937 mm^-1, R=0.039 6 and wR=0.102 6. The compound 1 exhibits one-dimensional chain structures, which are further stacked through π-π interactions to form supramolecular layers. Solid-state luminescent spectrum of the complex 1 indicates intense fluorescent emission. CCDC: 679004.     

Lindqvist型钼酸盐修饰的碳纳米管二阶非线性光学性质的理论研究

利用密度泛函理论(DFT)方法研究了[Mo₆O₁₉]^2-修饰的单壁碳纳米管的非线性光学(NLO)性质. 结果表明, [Mo₆O₁₉]^2-修饰的单壁碳纳米管作为特殊的有机-无机杂化体系, 具有显著的二阶非线性光学响应. 通过调整[Mo₆O₁₉]^2-与纳米管之间的角度, 体系的稳定性显示出规律性的变化趋势, 且二阶NLO响应发生了变化. 对静场二阶极化率(β_vec)有主要贡献的电子跃迁特征表明, [Mo₆O₁₉]^2-与碳纳米管之间角度的改变影响了分子内的给受体特征. 当角度达到30°时, 化合物显示出最大的β_vec值, 此时杂多阴离子簇为电子受体, 而碳纳米管为电子给体. 此外, 在碳纳米管的端位连接电子给体(如氨基)可有效地增大β_vec值.