硫化银/凹凸棒的Ag+选择电极

以硝酸银、凹凸棒石和硫代乙酰胺为原料制得硫化银/凹凸棒-Ag₂S/ATT电极,并探讨了硫代乙酰胺配比、增塑剂用量、膜厚度以及溶液pH值等因素对电极性能的影响. 结果表明,新型银离子选择电极有较好的能斯特响应,其响应斜率48.0 mV·decade^-1,Ag⁺浓度线性响应范围1.0×10^-1 ~ 1.0×10^-6 mol·L^-1. 在pH = 2.0 ~ 8.0溶液中该电极电势可稳定72 h,对常见阳离子如Na⁺、Ca²⁺、Fe²⁺、Cu²⁺等呈现较强的抗干扰能力.     

离子选择电极电位滴定法有机化合物中硼的快速微量分析

有机硼化合物在分解后通常转化为硼酸,需以甘露糖醇使其形成络合物,再用标准氢氧化钠溶液滴定^[1]。氧瓶分解法分解有机硼化合物,常需在样品燃烧前于样品内加入蔗糖^[2]、氢氧化钾^[3]或EDTA二钠盐^[4]。Gadson等^[5]在含硼无机溶液中加入少量10％氢氟酸,10分钟内形成BF₄^-,然后用流动载体氟硼酸根离子选择电极直接电位法进行测定。由此,我国刘成梁等^[4]首次提出氟硼酸根离子选择电极标准添加法,应用于有机硼元素微量分析。     

基于2,3-丁二酮双缩氨基硫脲为中性载体的新型银离子选择性电极的研究

研究了基于2,3-丁二酮双缩氨基硫脲为中性载体的聚氯乙烯(PVC)膜电极, 该电极对银离子(Ag^＋)具有优良的电位响应性能. 在pH＝3.0的NaOH-HNO₃体系中, 该电极对Ag^＋电极电位呈现近能斯特响应, 线性响应范围为3.0×10^－6～1.0×10^－2 mol/L, 斜率为52.6 mV/decade (20 ℃), 检测下限为1.0×10^－6 mol/L. 相对于常见的阳离子, 该电极对Ag^＋表现出良好的选择性. 采用交流阻抗技术研究了电极响应机理, 并将电极初步应用于回收率实验, 结果令人满意.     

水杨醛缩邻苯二胺双席夫碱敏感膜Cu(Ⅱ)离子选择性电极及SCN-的测定

用水杨醛和邻苯二胺合成了水杨醛缩邻苯二胺双席夫碱（SPS）,将其作为中性载体与碳粉混合,以液体石蜡为粘合剂,制备出能斯特响应铜(Ⅱ)离子选择性电极,应用于SCN^-的测定。 SCN-浓度在1.0×10^-6~1.0×10^-2 mol/L之间时该电极对其具有能斯特响应,检测下限为4.0×10^-7 mol/L。 在pH值为3.5~4.6的SCN^-溶液中,电极的响应时间均小于30 s。电极的稳定性好,灵敏度高,使用寿命长,已用于废水中SCN^-的分析。     

以1,1,1-三(N-甲基-N_苯基氨基羰甲氧甲基)丙烷为载体的钙离子选择电极

报道了以三脚架化合物1,1,1_三 (N_甲基_N_苯基氨基羰甲氧甲基 )丙烷 (TMPP)为载体的钙离子选择电极的研制;探讨了增塑剂、载体浓度、pH等因素对电极性能的影响 ;结果表明电极对钙离子有较好的近能斯特响应 ,相应的斜率为27.6 mV/pcCa2+ ,线性响应范围为5×10-5 ～5×10-2 mol/L,检出限为2.3×10-5mol/L ;电极在pH4～13范围内具有强的抗干扰能力 ,并具有很好的重复性和稳定性 ;该电极作为钙离子选择电极 ,用于乳酸钙口服液中钙含量的测定 ,取得了满意的结果     

碳纳米管电极上辣根过氧化物酶的直接电化学

制备了碳纳米管修饰玻碳电极(CNT/GC).将辣根过氧化物酶(HRP)固定在CNT/GC电极表面,形成HRP-CNT/GC电极.研究了HRP的直接电子转移.实验结果表明,HRP在CNT/GC电极表面能进行有效和稳定的直接电子转移反应,其循环伏安曲线上表现出一对良好的、几乎对称的氧化还原峰;式量电位E^0'几乎不随扫速(至少在20～100 mV/s的扫速范围内)而变化,其平均值为(-0.319±0.002) V (vs. SCE, pH 6.9); HRP在CNT/GC电极表面直接电子转移的速率常数为(2.07±0.56) s^-1;式量电位E^0'与溶液pH 的关系表明HRP的直接电化学是(1e+1H⁺)的电极过程.进一步的实验结果显示,固定在CNT/GC电极表面的HRP能保持其对H₂O₂还原的生物电催化活性,而且能快速地响应H₂O₂浓度的变化.本文制备碳纳米管修饰电极和固定酶的方法具有简单和易于操作等优点,可用于获得其它生物氧化还原蛋白质和酶的直接电子转移.     

用季铵盐定域体制备高碘酸根离子电极的研究

实验比较了若干种长链季铵盐制备高碘酸根离子电极,以十六烷基三辛基高碘酸季铵盐(HTOA-IO₄)制备的PVC膜电极性能较佳,能斯特响应区间为1.0×10^-1-6.3×10^-8M,检测下限1.0×10^-8M,工作pH范围2.5-7.5,高碘酸在溶液中存在复杂平衡,依据pH-电位曲线,认为电极响应的Ⅰ(ⅥI)离子的主要形态为IO₄^-,据此用电位法测试了H₅IO₆的酸离解常数:K₁=5.70×10^-4,K₂=1.97×10^-7,与文献值相符,测试了不同离子的电位选择性系数。     

基于金纳米棒-壳聚糖复合膜的葡萄糖生物传感器

本文采用金纳米棒-壳聚糖复合膜固定葡萄糖氧化酶构建电流型葡萄糖生物传感器.通过电化学交流阻抗法和循环伏安法对酶膜状态进行了表征,得到了相应的等效电路和动力学参数.实验结果表明,金纳米棒-壳聚糖复合膜可以辅助电子传递,提高电极的电流响应,并使生物传感器的使用温度范围有很大的扩展.此传感器表现出对葡萄糖溶液浓度的优良响应,线性范围在2.78×10^-5mol/L—2.22×10^-3mol/L,响应灵敏度约为7.819μA·cm^-2(mmol/L)^-1,表观米氏常数为10mmol/L.本工作还研究了温度和溶液pH值对电极电流响应的影响.     

原位烷基化调控无机-有机杂化类钙钛矿材料的结构及其性能※

无机-有机杂化类钙钛矿材料由于结构可调和独特的光电特性而引起了人们的广泛关注. 通过选用不同的烷基化溶剂, 一步水热法原位合成了两种新型的无机-有机杂化材料——二维(2D)结构的[(Me₃)ODA(Me₃)]₃Pb₅I₁₆ (1)和一维(1D)结构的[H(Et₂)ODA(Et₂)H]Pb₂I₆•H₂O (2) (ODA=4,4-二氨基二苯醚). 化合物1由2D的无机类钙钛矿层[Pb₅I₁₆]^6–和有机阳离子[(Me₃)ODA(Me₃)]²⁺组成, 化合物2由1D无机类钙钛矿链[Pb₂I₆]^2–、有机阳离子[(Et₂)ODA(Et₂)]²⁺和水分子组成. 实验表明, 两种不同维度的化合物虽然都具有典型的半导体性能, 但却表现出不同的化学稳定性以及光、电等物理特性. 其中, 化合物1对波长为400~700 nm的光呈现出明显的光电响应, 而化合物2在对水和有机溶剂表现出良好稳定性的同时, 还表现出优异的湿敏响应性能.     

氮掺杂部分石墨化碳/钴铁氧化物复合材料的制备及电化学性能

以甲壳胺（CTS）和钴、铁盐作有机前体与反应物,采用共沉淀法制备了CTS/钴铁层状双金属氢氧化物复合物.样品经过氩气氛、空气氛煅烧,生成氮掺杂部分石墨化碳/钴铁氧化物复合材料（N-PGC/CoFe-TMOs）.CTS热解且被过渡金属催化生成部分石墨化碳,同时原位氮掺杂,氮/碳原子比例约为1/18.N-PGC/CoFe-TMOs具有大孔和介孔结构,用作超级电容器电极材料兼有双电层电容与赝电容特征.在2 A·g^-1电流密度下,复合物比电容达到671.1 F·g^-1,远大于纯钴铁氧化物比电容283.3 F·g^-1,复合物具有典型的协同效应.电流密度增加到10 A·g^-1时,N-PGC/CoFe-TMOs比电容为573.3 F·g^-1,经过5000次充放电循环,复合物比电容保留率为66.4%.制备方法简便、通用,煅烧过程可一步制备氮掺杂的部分石墨化碳并与过渡金属氧化物复合,产物电化学性能优异.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.