镍纳米粒子-离子液体修饰碳糊电极的制备及其对多巴胺的测定

制备了镍纳米粒子-离子液体修饰电极,在0.1 mol/L磷酸缓冲溶液(pH 6.0)中研究了多巴胺(DA)在修饰电极上的电化学行为.与裸电极相比,DA在该修饰电极上的氧化还原电位明显降低,氧化还原反应的峰电流明显增大,DA的峰电流与其浓度在2.0×10~(-8) ～1.0×10~(-4) mol/L范围内呈良好的线性关系,检出限为6.5×10~(-9) mol/L.该修饰电极对抗坏血酸具有明显的抗干扰能力.     

镍纳米粒子修饰碳糊电极直接电催化鸟嘌呤的研究

将镍纳米粒子与石蜡、石墨按照一定比例混合制备镍纳米粒子修饰碳糊电极,采用循环伏安法(CV)对修饰碳糊电极进行电化学表征,在0.1 mol/L B-R缓冲溶液(pH4.5)中研究了鸟嘌呤在该修饰电极上的电化学行为。结果表明,与裸碳糊电极相比,以掺杂法制备的镍纳米粒子修饰电极能够明显降低鸟嘌呤的过电位,增大其氧化电流,很好地催化氧化鸟嘌呤。在优化的实验条件下,鸟嘌呤在该修饰电极上的氧化峰电流与其浓度在1.0×10-5~5.0×10-4mol/L范围内呈良好的线性关系,检出限(3σ)为7.5×10-6mol/L。     

高选择性的镍基无酶葡萄糖微传感器的研制及应用

采用电刻蚀法制得微镍电极,通过循环伏安法在微镍电极上修饰过氧化聚吡咯膜,利用葡萄糖在碱性条件下在该修饰电极上的电催化氧化性质,制备了新型的抗干扰的无酶葡萄糖微传感器;研究了其电化学氧化机理,在较低的碱性(pH=12.0)和较低的氧化电位( 0.47 V)条件下,微镍修饰电极上产生的Ni(Ⅲ)能直接将葡萄糖氧化为葡萄糖酸内酯,产生的安培响应与葡萄糖浓度在5.0×10-6 ～1.1×10-3 mol/L范围内呈线性关系;检出限为2.4×10-6 mol/L.该微传感器灵敏度高(30.4 nA/μM)、选择性好(20倍AA和UA不干扰)、响应快(小于3 s)、重现性好,而且制作简单、使用方便,已用于流动注射分析(FIA)测定血清中血糖含量.     

一氧化氮在水杨醛谷氨酸合镍修饰碳黑微电极上的电催化氧化

制备了水杨醛谷氨酸合镍修饰碳黑微电极,试验了修饰电极对一氧化氮的电催化氧化性能。试验结果表明,在pH 6.8的磷酸盐中,一氧化氮在该电极上的线性范围为4.0×10-8~1.0×10-5mol.L-1;检出限(3σ)为1.0×10-8mol.L-1。将此电极用于3种模拟样品的分析,并在此基础作回收率试验,测得RSD(n=8)值在1.9%~2.8%之间,回收率在97%~105%之间。在一氧化氮浓度1.0×10-6mol.L-1的水平上进行精密度试验,测得RSD(n=10)为2.2%。     

电化学方法制备石墨烯-铁氰化镍复合物及对抗坏血酸的电催化氧化研究

采用电化学还原方法制备了铁氰化镍-石墨烯复合薄膜电极,扫描电子显微镜(SEM)表征电还原石墨烯和铁氰化镍-石墨烯复合材料的表面形貌。采用循环伏安和计时电流技术研究了该修饰电极对抗坏血酸(AA)的电催化氧化性能,据此建立了一种测定AA的电化学分析新方法。由于石墨烯和铁氰化镍纳米颗粒之间的协同效应,使得该复合修饰电极对抗坏血酸具有优异的电催化活性。在0.1 mol/L pH 7.00的PBS溶液中,抗坏血酸的催化氧化电流与其浓度在1.0×10-4~7.0×10-4mol/L范围内呈良好的线性关系,检出限为3.1×10-5mol/L(S/N)。     

多巴胺在镍(Ⅱ)与水杨醛谷氨酸配合物修饰的碳黑微电极上的电化学行为

制备了水杨醛谷氨酸合镍修饰碳黑微电极,在JP-303极谱分析仪上研究了多巴胺(DA)在该修饰电极上的电化学行为,试验结果表明,在pH 7.0的磷酸盐缓冲介质中,多巴胺在该修饰电极上其峰电流增强达3倍之多.产生一灵敏的氧化峰,在0.14 V处峰电流与DA浓度在2.0×10-7～1.0×10-3mol L-1范围内呈线性关系,检出限(3σ)为1.0×10-7mol·.L-1,应用于盐酸多巴胺注射剂中多巴胺的测定,测定结果的RSD(n=7)值小于3.5%,回收率为96%～103%.     

芦丁修饰电极研究多巴胺的电化学响应

通过循环伏安法(CV)制备了芦丁修饰电极,研究多巴胺(DA)在修饰电极上的电化学行为.结果表明,芦丁修饰膜对DA的氧化有明显的催化作用,并且可以消除抗坏血酸(AA)对DA测定的干扰.DA的浓度在1.0×10-7～9.5×10-6 mol/L范围内与其氧化峰电流呈线性关系,相关系数为0.9996,检出限为1.0×10-8 mol/L.将该修饰电极用于注射液样品中DA的测定,结果表明该修饰电极可用于实际样品分析.     

抗坏血酸在纳米银DNA修饰电极上的电化学行为研究

利用电化学生长法制备了纳米银DNA修饰电极.在pH 4.1的磷酸盐(PBS)缓冲溶液中研究了抗坏血酸(AA)在该电极上的电化学行为,实验得到电荷传递系数α=0.41、扩散系数D=1.22×10-5 cm2 /s.建立了利用修饰电极催化作用快速测定抗坏血酸的方法,修饰电极对抗坏血酸的催化氧化峰与抗坏血酸的浓度分别在1.0×10-2～5.0×10-5 mol/L、5.0×10-6～5.0×10-8 mol/L范围内呈线性关系,检出限为1.0×10-9 mol/L.该方法快速、灵敏.     

对乙酰氨基酚在聚刚果红修饰电极上的伏安测定

应用循环伏安法于玻碳电极修饰聚刚果红薄膜,并研究对乙酰氨基酚(ACOP)在该修饰电极上的电化学行为.实验表明,聚刚果红修饰电极对ACOP具有良好的电催化性能.在2.0×10-7~2.0×10-6mol.L-1ACOP浓度范围内,其差示脉冲伏安峰电流随浓度变化呈良好的线性关系,检测限为4.0×10-8mol.L-1.该法可用于实际样品的含量测定.     

纳米铁氰化镍修饰铝电极对抗坏血酸的电催化氧化

利用多孔阳极氧化铝作模板,用化学修饰方法在铝基体上制备了纳米铁氰化镍修饰电极。研究了修饰电极的电化学特征及其电催化氧化抗坏血酸的行为。结果表明,纳米铁氰化镍修饰铝电极的循环伏安图上呈现一对可逆氧化还原峰。检测抗坏血酸,纳米铁氰化镍修饰铝电极比铁氰化镍修饰铝电极有更高的灵敏度。用安培法测定抗坏血酸,线性范围为1×10-6～1.5×10-2mol/L,检出限为2.4×10-7mol/L。本方法应用于实际样品中抗坏血酸的检测,结果令人满意。     

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.