电化学发光分析法测定氨基硫脲

基于在碱性介质中,氨基硫脲对罗丹明B的电化学发光具有抑制作用,建立了测定氨基硫脲的电化学发光新方法。运用阶跃脉冲电解方式,在最佳实验条件下,相对电化学发光强度与氨基硫脲的浓度在1.0×10-10～1.0×10-6mol/L范围内呈线性关系,检出限为8.0×10-11mol/L,该法可应用于水样中氨基硫脲含量的测定。     

基于电化学平行催化波效应与化学发光信号传感相偶合测定V（V）的分析新方法

研究发现,V(V)可在含有H2O2的碱性介质中,在石墨电极表面还原产生钒的平行催化波效应.与此同时,当上述溶液中含有适量的丁基罗丹明B时,丁基罗丹明B可与钒催化还原H2O2的产物反应产生灵敏的电化学发光信号.测定了该体系电化学反应时间和化学发光反应时间,验证了电化学平行催化效应与化学发光结合的可能性.据此建立了测定钒的电化学发光分析新方法,同时提出了电化学平行催化渡效应与化学发光信号传感相结合提高电化学分析方法灵敏度的新思路.在最佳的实验条件下,该方法测定V(V)的线性范围为4.0×10-7 mol/L～8.0×10-5mol/L,检出限为3×10-8mol/L(以3σ计).     

基于电化学平行催化波效应与化学发光信号传感相偶合测定V(Ⅴ)的分析新方法

研究发现,V(Ⅴ)可在含有H2O2的碱性介质中,在石墨电极表面还原产生钒的平行催化波效应。与此同时,当上述溶液中含有适量的丁基罗丹明B时,丁基罗丹明B可与钒催化还原H2O2的产物反应产生灵敏的电化学发光信号。测定了该体系电化学反应时间和化学发光反应时间,验证了电化学平行催化效应与化学发光结合的可能性。据此建立了测定钒的电化学发光分析新方法,同时提出了电化学平行催化波效应与化学发光信号传感相结合提高电化学分析方法灵敏度的新思路。在最佳的实验条件下,该方法测定V(Ⅴ)的线性范围为4.0×10-7mol/L~8.0×10-5mol/L,检出限为3×10-8mol/L(以3σ计)。     

Determination of Benzhexol Hydrochloride by Electrochemiluminescence in the Presence of Sodium Dodeeyl Benzene Sulfonate

在十二烷基苯磺酸钠(SDBS)存在下,考察了盐酸苯海索(BH)- Ru(bpy)2+3体系的电化学及其发光行为.结果表明,BH对Ru(bpy)2+3体系的电化学发光具有增敏效应;在SDBS存在下,BH对Ru(bpy)2+3体系电化学发光的增敏效应显著增强,发光强度提高约16倍.据此建立了一种高效、简便的BH电化学发光新方法.在最佳实验条件下,BH的浓度在4.0×10-7～1.0×10-4 mol/L范围内与相对发光强度呈线性关系(r=0.995 5),检出限(S/N=3)为1.11×10-9 mol/L;连续平行测定1.0×10-5 mol/L BH溶液10次,发光强度的RSD为3.29％.样品的回收率为96％～108％,RSD为4.3％.该方法样品前处理简单,具有较高的选择性和灵敏度,用于实际样品中BH的测定,结果满意.     

十二烷基苯磺酸钠-盐酸苯海索-Ru(bpy)2+3体系的电化学发光行为研究及应用

在十二烷基苯磺酸钠(SDBS)存在下,考察了盐酸苯海索(BH)-Ru(bpy)32+体系的电化学及其发光行为。结果表明,BH对Ru(bpy)32+体系的电化学发光具有增敏效应;在SDBS存在下,BH对Ru(bpy)32+体系电化学发光的增敏效应显著增强,发光强度提高约16倍。据此建立了一种高效、简便的BH电化学发光新方法。在最佳实验条件下,BH的浓度在4.0×10-7～1.0×10-4 mol/L范围内与相对发光强度呈线性关系(r=0.995 5),检出限(S/N=3)为1.11×10-9 mol/L;连续平行测定1.0×10-5 mol/L BH溶液10次,发光强度的RSD为3.2%。样品的回收率为96%～108%,RSD为4.3%。该方法样品前处理简单,具有较高的选择性和灵敏度,用于实际样品中BH的测定,结果满意。     

双波长共振散射比率法测定十二烷基苯磺酸钠的研究

基于表面活性剂SDBS与罗丹明B的结合反应发展了一种测定SDBS的双波长共振散射比率法.在BR缓冲溶液介质中,SDBS能与RB发生反应,其位于373.0nm的特征共振光散射信号大大增强.通过分别测定I373.0和Ⅰ685.0/I650.0来检测SDBS,当罗丹明B的浓度为1.0×10-4 mol/L时,以Ⅰ373.0为...     

氧化石墨烯修饰碳离子液体电极同时测定鸟嘌呤和腺嘌呤

以离子液体1-丁基-3-甲基咪唑六氟磷酸盐为粘合剂制备了碳糊电极,然后将氧化石墨烯滴涂到碳糊电极表面制成了一种新型的氧化石墨烯修饰碳离子液体电极。研究了鸟嘌呤和腺嘌呤在修饰电极上的电化学行为。实验结果表明,在0.1 mol/L醋酸盐缓冲溶液中(pH4.5),鸟嘌呤和腺嘌呤在该修饰电极上具有良好的电化学行为,在2.0×10-7～1.5×10-5mol/L浓度范围内鸟嘌呤和腺嘌呤的浓度在该电极上与电化学响应信号呈良好的线性关系,相关系数分别为为0.992和0.996。信噪比为3时,检出限为1.0×10-8mol/L。     

毛细管电泳-电化学发光法检测泛昔洛韦

建立了毛细管电泳-电化学发光(CE-ECL)法检测泛昔洛韦的新方法。考察了检测电位、运行高压、进样电压与时间、检测池中磷酸盐的pH值、运行缓冲溶液的pH值及浓度等测试条件对电化学发光强度的影响。在最优化的实验条件下,泛昔洛韦在5.0×10-6～2.5×10-4mol/L浓度范围内与电化学发光强度有良好的线性关系,相关系数为0.9973,检出限为3.5×10-6mol/L。该法灵敏度高,选择性好,可应用于泛昔洛韦原料药及制剂的质量控制。初步探讨了CE-ELC检测泛昔洛韦的机理。     

十二烷基磺酸钠-盐酸维拉帕米-联吡啶钌体系电化学发光及其应用

在十二烷基磺酸钠(SDS)中,考察了盐酸维拉帕米-Ru(bpy)32+体系在金电极上的电化学及其发光行为。结果表明:SDS对体系的电化学反应和电化学发光强度具有显著的增敏作用。据此,建立了一种高效、简便的测定盐酸维拉帕米的电化学发光新方法。在最佳实验条件下,盐酸维拉帕米浓度在1.0×10-4～1.0×10-7mol/L范围内与相对发光强度呈线性关系,检出限(S/N=3)为5.2×10-10 mol/L,连续平行测定1.0×10-5 mol/L盐酸维拉帕米5次,发光强度的RSD为3.1%。对样品进行回收实验,回收率在98.7%～106.5%之间,RSD为3.0%(n=5)。本方法具有较高的选择性和灵敏度,样品处理简单,用于实际样品的测定,结果满意。     

CdSe量子点修饰电极电化学发光法测定叶酸

制备了水溶性的CdSe量子点,用紫外光谱和荧光光谱对其进行了表征.并将其修饰到金电极的表面,得到了CdSe量子点修饰电极(CdSe/GE),研究了其电化学发光性质.结果表明:在强碱介质中,CdSe/GE对鲁米诺电化学发光具有增敏作用,在此发光体系中加入叶酸后,会产生进一步增强的电化学发光信号,由此建立了电化学发光检测叶酸的新方法.考察了缓冲溶液pH值、鲁米诺的浓度和扫速等条件对电化学发光强度的影响.在优化的实验条件下,叶酸在1×10~(-13)~1.1×10~(-4) mol/L浓度范围内与相对发光强度(ΔI)呈现良好的线性关系,检测限为6.0×10~(-14) mol/L(S/N=3),并用于市售叶酸片剂中叶酸的测定,得到令人满意的实验结果.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

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.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

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.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.