自组装ITO/双层磷脂膜的制备及其光电行为研究

在ITO(Indium-tin-oxide)导电玻璃电极上制备上自组装双层磷脂膜和经C60修饰的双层磷脂膜,研究了这种自组装双层磷脂膜的光电行为,考察了偏压、溶液中的给体和受体的浓度对自组装膜光电流强度的影响,讨论了C60分子对光电子跨膜传递过程的促进作用。     

金属富勒烯[Dy@C_(82)(I)]膜的电化学研究

研究并对比了金属富勒烯Dy @C82 的主要异构体Dy @C82 (I)固体膜在有机溶剂乙腈及水溶液中的电化学性质 .在乙腈溶液中 ,Dy @C82 (I)膜的电化学行为不同于其溶于有机溶剂中的电化学行为 ,前两个还原峰与其对应的再氧化峰之间存在大的分裂 .但是 ,经过还原及再氧化后的Dy @C82 (I)膜却存在一对对称性很好的氧化及再还原峰 .解释为经过还原后的Dy @C82 (I)膜的结构有利于进一步氧化 ,而不需要结构重排 ;在水溶液中 ,Dy @C82 (I)膜的电化学行为不同于其在乙腈溶液中 ,却类似于其有机溶液在Pt电极上的电化学行为 ,出现了对称性很好的三对还原峰及一对氧化峰 .在水溶液中 ,Dy @ C82 (I)的前三价负离子及一价正离子是稳定的 .利用紫外 -可见 -近红外 (UV Vis NIR)光谱及扫描电镜 (SEM)等技术对膜的性质及表面形貌等进行了表征     

膜电阻对自组装膜修饰电极电化学行为的影响

应用循环伏安和交流阻抗技术研究了 16烷基硫醇自组装膜修饰的金电极在Fe(CN) 63 - /Fe(CN) 64 - 溶液中的电化学行为 .无“针孔”缺陷的自组装膜对溶液与基底间的界面电子转移具有强烈的阻碍作用 ,当过电位较大时 ,In(I/ η)对 η1/2 之间具有良好的线性关系 .通过对Au/SAM /Hg模拟体系的电流———电压曲线进行测定 ,得到了自组装膜膜电阻的特征 .指出由于膜电阻的存在 ,自组装膜修饰电极在Fe(CN) 63 - /Fe(CN) 64 - 溶液中的行为实质上反映了膜自身的电阻特征     

苝醌／富勒烯C60超分子与电子给体的电子转移作用

利用紫外-可见吸收光谱、瞬态吸收光谱及x射线衍射等方法研究了苝醌染料竹红菌素镁离子配合物(Mg2+-HA)与富勒烯C60的相互作用.结果表明,Mg2+-HA与C60在溶液和固体状态下都能够形成稳定的超分子.Mg2+-HA 存在条件下,C60 能够溶于多种极性溶剂,在二甲基亚砜(DMSO)中的溶解度能够达到1×10-4mol·L-1.作为超分子体系中的光捕获分子,Mg2+-HA 能显著地提高C60 与N,N.二甲基苯胺(DMA)的光诱导电子转移反应效率,生成的C60 负离子自由基的电子自旋共振光谱(ESR)信号强度比未加入Mg2+-HA 时增强了9倍左右.     

苝醌/富勒烯C60超分子与电子给体的电子转移作用

利用紫外-可见吸收光谱、瞬态吸收光谱及X射线衍射等方法研究了苝醌染料竹红菌素镁离子配合物(Mg2+-HA)与富勒烯C60的相互作用. 结果表明, Mg2+-HA与C60在溶液和固体状态下都能够形成稳定的超分子. Mg2+-HA存在条件下, C60能够溶于多种极性溶剂, 在二甲基亚砜(DMSO)中的溶解度能够达到1×10^-4 mol·L^-1. 作为超分子体系中的光捕获分子, Mg2+-HA能显著地提高C60与N,N-二甲基苯胺(DMA)的光诱导电子转移反应效率, 生成的C60负离子自由基的电子自旋共振光谱(ESR)信号强度比未加入Mg2+-HA时增强了9倍左右.     

表面修饰富勒烯的聚酰胺-胺树枝状分子与生物膜的相互作用研究

采用粗粒化的分子动力学模拟,研究了末端修饰富勒烯(C60)的聚酰胺-胺(PAMAM)树枝状分子在水溶液中的结构变化以及其与磷脂膜相互作用行为.发现修饰后的PAMAM分子大小随嫁接数目的增多而减小,而形状变化并不明显,分子仍是近球形结构;同时发现C60分子因疏水作用聚集在一起.与膜作用后,因C60分子插入到双层膜内,导致分子由球形稍微向椭球形改变,分子大小也稍微增大.同时发现PAMAM分子紧紧分布在磷脂膜表面,局域膜厚度变小.     

含载体D2EHPA的更新型支撑液膜体系对三价钆的分离

研究了以聚偏氟乙烯膜为支撑体, 二-(2-乙基己基)磷酸(D2EHPA)为流动载体, 煤油和D2EHPA的混合溶液作为膜溶液, 膜溶液和解析剂HCl溶液组成更新相的更新型支撑液膜(RSLM)中Gd(III)的分离行为|考察了料液pH、更新相HCl浓度、膜溶液与HCl溶液体积比、不同载体浓度对Gd(III)分离的影响, 得出了Gd(III)最优分离条件为: 更新相HCl溶液浓度4.00 mol/L, 膜溶液与HCl溶液体积比4∶3, 载体浓度控制在0.160 mol/L, 料液相中pH为4.80. 在最优分离条件下, 当Gd(III)的初始浓度为1.00×10^－4 mol/L时, 35 min Gd(III)分离率达到95.7%. 最后根据传质定律和界面化学理论提出了Gd(III)在RSLM中的传质动力学方程.     

N-(4-乙烯基)苄基咪唑共聚物的合成及与钴卟啉络合物的氧结合性能

研究了N-(4-乙烯基)苄基咪唑单体及其与甲基丙烯酸辛酯共聚物(PBIOM)的合成与表征,以及咪唑基有机或聚合物配位体与钴卟啉(CoP)络合物的氧结合性能.合成的PBIOM重均分子量和咪唑基含量分别由GPC和元素分析方法测定,结果为3.4×105和57 mol%.PBIOM或苄基咪唑(BIm)中的咪唑基与CoP在溶液中配位,得到的CoP-PBIOM或CoP-BIm络合物具有快速、可逆的氧结合特性.相同氧气分压下CoP-BIm络合物在三氯甲烷溶液中的氧结合百分率略大于CoP-PBIOM络合物.CoP-PBIOM络合物固体膜的氧结合亲和力大于三氯甲烷溶液中的氧结合亲和力.60℃下CoP-PBIOM固体膜的氧结合半衰期为40.7 h,而CoP-BIm固体膜为8.8 h,表明聚合物配位体显著提高了CoP络合物的氧结合寿命.     

C60-蒽吡咯烷的合成及非线性光学性质的研究

设计合成了一种新的C60-蒽吡咯烷衍生物1.以1H NMR,13C NMR,FTIR,UV-Vis和FAB MS进行了结构表征,测量其在甲苯溶液中的紫外光谱、荧光发射光谱,并在最大发射波长下测得其荧光寿命为5.44 ns,利用皮秒激光光源,采用Z扫描技术测定了分子1的三阶非线性超极化率γ(3)为6.60×10-33 esu,大于C60的文献报道值7.5×10-34 esu.说明C60-蒽吡咯烷衍生物1在激光激发下发生了加成基团蒽与母体C60之间的分子内能量转移和电荷传递.通过理论化学计算进一步验证了电荷转移的发生.     

一种扩大汞膜电极可用电位范围的新方法及应用

研究了玻碳汞膜电极在次黄嘌呤溶液中的电化学行为及在此溶液中对抗坏血酸的电催化性能.结果表明:底液中加入一定量的次黄嘌呤能很好地抑制汞在较高的电位下溶出,并且汞膜电极在此溶液中有较好的稳定性,从而扩大了汞膜电极可用电位范围,为在较高电位下应用汞膜电极测定抗坏血酸提供了条件.在pH 1.81缓冲溶液中,抗坏血酸在汞膜电极上于0.25 V处出现灵敏的不可逆氧化峰(以银-氯化银电极作参比电极),峰电流在5×10-5～2.4×10-3mol·L-1范围内与浓度呈线性关系;检出限分别为8×10-6mol·L-1.该方法用于维生素C片剂中抗坏血酸含量的测定,分析结果的相对标准偏差(n=7)为1.3%,回收率在101.2%～104.5%之间.     

Two-component polymer films of palladium and fullerene with covalently linked crown ether voids: effect of cation binding on the redox behavior

Redox active films have been generated via electrochemical reduction in a solution containing palladium(II) acetate and fulleropyrrolidine with covalently linked crown ethers, viz., benzo-15-crown-5 and benzo-18-crown-6. In these films, fullerene moieties are covalently bonded to palladium atoms to form a polymeric network. Films show ability to coordinate alkali metal cations from the solution. Therefore, in solutions containing salts of alkali metal cations, benzo-15-crown-5-C₆₀/Pd and benzo-18-crown-6-C₆₀/Pd films are doped with cations coordinated by crown ether moiety and anions of supporting electrolyte which enter the film to balance positive charge. These films are electrochemically active in the negative potential range due to the reduction of the fullerene moiety. Reduction of the polymer is accompanied by the transport of supporting electrolyte ions between solution and solid phase. In solution containing alkali metal salts, the process of film reduction is accompanied by the transport of anions from the film to the solution. In the presence of tetra(alkyl)ammonium salts, transport of cations from the solution to the film takes place during the polymer reduction.     

氟化钾催化含氢烷氧基硅烷的歧化反应

氟化钾催化含氢烷氧基硅烷的歧化反应张增佑，尚坚，周秀中（南开大学元素有机化学研究所化学系，天津，５０００７１）关键词歧化反应，氟化物，催化，烷氧基硅烷早在７０年代初期Ａｋｌｉｒｅｍ［１］就报道了氟化物可催化硅氢化物醇解。关于氟化物活化Ｓｉ—Ｈ键的实质...     

Regioselective synthesis and properties of novel [60]fullerene bisadducts containing a dibenzocrown ether moiety

The reactions of [60]fullerene with bis-o-quinodimethane precursors 3, 4, and 5 containing a dibenzo-18-crown-6, 24-crown-8 and 30-crown-10 moiety, respectively, were investigated. Both 3 and 4 provided trans-4 bisadducts 6a and 7a, respectively, as major product, though the selectivity in the latter was lower than that in the former. As minor product, 6b (cis-2) was produced from 3, while 7c (e) as well as 7b (cis-2) were produced from 4. Precursor 5 exclusively afforded e bisadduct 8 without any other regioisomers. These bisadducts showed different ionophoric properties from one another; for instance, 6a and 7b exhibited a high complexing ability toward the K+ ion, while 6b hardly showed complexation with any alkali metal ions. The selectivity coefficients (K(Na,K)(pot)) of 6a and 7b toward K+ over Na+ ion, determined with an ion-selective electrode, were much higher than that of dibenzo-18-crown-6.     

Caesium-selective PVC membrane electrodes based on bis(crown ether)s

Caesium-selective PVC membrane electrodes based on bis(crown ether)s containing benzo-18-crown-6 moieties were prepared using two kinds of plasticizers. Selectivity coefficients for various interfering monovalent ions were determined by the mixed solution method, and were found to relfect the complexing property and extractability of the bis-(benzo-18-crown-6)s. The electrochemical selectivity was also compared with that of the corresponding monocyclic analog and valinomycin.     

NMR Studies of Mixed-Ligand Lanthanide (III) Complexes. Peculiarities of Molecular Structure, Dynamics and Paramagnetic Properties for Cerium Subgroup Chelates with Crown Ethers

The molecular structure, dynamics and paramagnetic properties of the complex cations [Ln(ptfa)₂ (18-crown-6)]⁺ in deuterated toluene were studied for Ln = La, Ce, Pr and Nd. The activation enthalpy values of 68 ± 5, 55 ± 15 and 60 ± 13 kJ mol^-1 for the 18-crown-6 conformationalinversion processes for the complexcations of Ce, Pr and Nd, respectively,were obtained. Quantitativeinvestigation of the lanthanide-induced chemical shifts shows a monotonic change of a spatial structure and magnetic susceptibility in comparison with the Bleaney predicted dependence. The free energy of molecular inversion activation for 18-crown-6 molecules in the complex cation [Ln(fod)₂(18-crown-6)]⁺ is 74 ± 9 kJ mol^-1 at 363 K, which is a little more than the value of the free energy of activation 64 ± 9 kJ mol^-1 at 363 K in the complex cation [Ln(ptfa)₂(18-crown-6)]⁺.     

Stability of Complexes of NH4 + with 18-Crown-6, Dicyclohexyl-18-Crown-6, Dibenzo-18-Crown-6 and Dibenzo-24-Crown-8 in Water Saturated Nitrobenzene

From extraction experiments with ²²Na tracer, the exchange extraction constants corresponding to the NH₄ ⁺(aq) + NaL⁺ (nb)NH₄L⁺(nb) + Na⁺ (aq) equilibrium taking place in the two-phase water-nitrobenzene system (L = 18-crown-6, dicyclohexyl-18-crown-6, dibenzo-18-crown-6 and dibenzo-24-crown-8; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Furthermore, the stability constants of the NH₄L⁺ complexes in nitrobenzene saturated with water were calculated; they were found to increase in the order dibenzo-24-crown-8 (DB24C8) < dibenzo-18-crown-6 (DB18C6) < dicyclohexyl-18-crown-6 (DCH18C6) < 18-crown-6 (18C6).     

双酚A 型聚冠醚的合成与性能

由于聚冠醚具有选择性配位阳离子的性能,同时具有毒性低、易于回收等优点,所以它们在相转移催化、金属分离浓缩等方面有重要的应用前景。我们曾报道用2,6-二(羟     

单臂脂环18-冠-6液晶的合成

本文合成了两种单臂脂环18-冠-6-液晶, 羟甲基 18-冠-6分别和4-(4'-正丁氧基苯甲酰氧基)苯甲酰氯或氯甲酸胆甾醇酯反应得到两种目标物,用DSC和偏光显微镜测定其相变温度,前者相变温度是T~K~N4.0℃和T~N~I33.5℃, 后者相变温度T~K~S-22.4℃, T~S~N6.8℃, T~N~I40.4℃, 用等克分子的硬脂酸和该冠醚液晶制成LB膜, 观察到Y型LB膜的特征.     

Two complexes of Sm(II) with crown ethers-electrochemical synthesis, structure and spectroscopy

Two complexes of divalent samarium have been synthesized by electrochemical reduction in methanol-tetrahydrofuran solutions: [Sm(18-crown-6)(ClO4)2] and [Sm(15-crown-5)2](ClO4)2. In [Sm(18-crown-6)(ClO4)2] the metal cation is ten-coordinate and its coordination sphere comprises six oxygen atoms of the crown ligand and four oxygen atoms from two perchlorate anions. [Sm(15-crown-5)2](ClO4)2 shows a sandwich structure with decacoordinate samarium located between two 15-crown-5 molecules. At 77 K both compounds show f-f luminescence originating from the 5D0 level, and also the 15-crown-5 complex shows a weak luminescence in the range 20000-25000 cm(-1), which has been tentatively interpreted as originating from 3P0 and 5H3 levels. At room temperature the emission of [Sm(15-crown-5)2](ClO4)2 is dominated by broad f-d bands. In the excitation spectra some Fano resonances have been observed. The 18-crown-6 compound is unstable, but the 15-crown-5 compound is fairly stable in air.     

Ultrathin conjugated polymer network films of carbazole functionalized poly(p-phenylenes) via electropolymerization

Ultrathin films of a cross-linked and chemically distinct conjugated poly(p-phenylene) network via electropolymerization are described. The amphiphilic network precursor was synthesized by incorporating the alkoxy carbazole group (-O(CH2)5Cb) to a poly(p-phenylene) (C6PPPOH) backbone. In order to investigate the combined thin film electrochemical and photophysical properties of poly(p-phenylene)s and polycarbazole conjugated polymers, C6PPPC5Cb was deposited on substrates using the Langmuir Blodgett Kuhn (LBK) method. The monolayer isotherm of the polymer, C6PPPC5Cb, showed a liquid expanded region slightly different from the parent polymer C6PPPOH. Multilayers (up to 30 layers) were transferred to different substrates such as quartz, gold coated LaSFN9 and ITO substrates for analysis. For conversion to a conjugated polymer network (CPN) film, the electroactive carbazole group was electropolymerized using cyclic voltammetry (CV) resulting in polycarbazole linking units. The differences in the film properties and corresponding changes in the electrochemical behavior indicate the importance of film thickness and electron/ion transport process in cross linked network films. From the electrochemical studies, the scan rate was found to have a considerable effect on electropolymerization with higher oxidation and reduction peak values found for the rigid network polymer compared to the uncrosslinked polymers.