TiO_2/12-磷钨杂多酸/金复合纳米材料的制备及电化学性能

采用水热法制备TiO2纳米管(TNTs),然后以12-磷钨杂多酸(PTA)作为交联剂,运用光催化方法在TiO2纳米管表面负载金纳米颗粒(GNPs),从而得到新型复合纳米材料——TNTs-PTA-GNPs;借助傅立叶变换红外光谱仪,X射线衍射仪和透射电子显微镜分析了新型复合纳米材料的结构及形貌,并利用循环伏安法测试了其电化学性能.结果表明,GNPs均匀分布在TNTs表面,从而大幅度改善纳米材料的导电性;但复合纳米材料中无游离的金纳米颗粒.与此同时,TNTs-PTA-GNPs纳米材料具有良好的生物相容性,且可促进酶与电极之间的直接电子转移.     

钛酸盐纳米管-聚苯胺-金纳米颗粒复合材料的制备及其生物电化学性能

采用水热法制备出钛酸盐纳米管(TNTs),然后使用氧化聚合法将苯胺聚合到TNTs表面生成聚苯胺(PANI),最终将金纳米粒子还原到PANI表面制备出三元复合纳米材料(TNTs-PANI-GNPs).其中PANI作为交联剂链接起TNTs和GNPs形成稳定和结合紧密的三元复合纳米材料,不同的光谱和显微图像技术证实了三元复合纳米材料的成功合成.我们将辣根过氧化物酶(HRP)与三元复合纳米材料充分混合均匀后涂抹于玻碳电极表面,伏安实验结果证明HRP已实现在TNTs-PANI和TNTs-PANI-GNPs修饰电极上的直接电子转移,而且后者相较于前者对过氧化氢的催化还原电流增强了大约74.9%.TNTs-PANI-GNPs复合纳米材料修饰的生物传感器的优越电化学性能主要归因于复合材料中TNTs、PANI和GNPs三者之间的协同作用,将优点最大化,将缺点最小化.     

纳米二氧化钛对辣根过氧化酶催化作用

将辣根过氧化物酶(HRP)固定在二氧化钛(TiO2)纳米颗粒或纳米管修饰玻碳电极(GC)上,形成纳米TiO2微粒/HRP修饰GC电极和TiO2纳米管/HRP修饰GC电极.比较了HRP在纳米TiO2微粒、TiO2纳米管电极上的直接电子转移反应.实验表明,HRP在TiO2纳米管电极表面更能有效地促进它的电活性中心发生电子交换反应.此外,还测定了HRP标记抗体的电化学性能,为抗原抗体免疫反应信号的选择提供了参考依据.     

电聚合构建HRP传感器检测有机过氧化物

利用电化学还原氧化石墨烯(GO)的方法将还原石墨烯(erGO)沉积在电极表面上,然后电沉积氧化锌纳米棒(ZnO)构成erGO/ZnO复合纳米材料修饰玻碳电极(GCE),最后通过电聚合中性红(NR)电子介体包埋法将辣根过氧化物酶(HRP)固定在GCE/erGO/ZnO表面制得GCE/erGO/ZnO/HRP-PNR(聚中性红)。用SEM和能谱对复合纳米材料进行了表征,通过电化学阻抗法和循环伏安法对修饰电极进行了探究,通过循环伏安法和计时电流法研究了GCE/erGO/ZnO/HRP-PNR对有机过氧化物的催化性能,结果该修饰电极对过氧化氢叔丁基(BHP)和过氧化氢异丙苯(CHP)都具有良好的检测性能。     

纳米TiO2-Pt修饰电极的制备及电催化活性

采用电化学合成前驱体直接水解法和电沉积法制备高活性纳米TiO2-Pt修饰电极，并使用扫描电子显微镜(SEM)对电极的表面形貌和结构进行了表征; 通过循环伏安法研究了纳米TiO2-Pt修饰电极在H2SO4溶液中的电化学行为以及对Mn2＋氧化为Mn3＋的电催化活性. 结果表明,纳米TiO2的晶粒大小约30 nm,修饰在纳米TiO2膜表面的Pt微粒呈现单分散状态,平均粒径约60 nm,纳米TiO2-Pt修饰电极的电化学性能优于纯Pt电极,对Mn2＋的电氧化具有高催化活性,非均相无隔膜电解氧化Mn2＋生成Mn3＋平均电流效率可达86％.     

基于AuNPs/PANI/TNTs纳米复合材料的电化学检测妥布霉素的适配体传感器（英文）

本文提出了一种新型的检测妥布霉素的电化学适配体传感器,以差分脉冲伏安法(DPV)作为检测技术,亚甲基蓝作为电化学响应信号.构建了以纳米复合材料金纳米粒子/聚苯胺/二氧化钛纳米管(AuNPs/PANI/TNTs)修饰玻碳电极的电极支架.通过透射电子显微镜和X-射线光电子能谱对纳米复合材料进行详细的表征.循环伏安图和电化学阻抗谱显示AuNPs/PANI/TNTs可以很好地增加电极的界面传导性能. DPV结果显示电流密度的响应和妥布霉素浓度之间存在一个很好的线性关系,并且得到一个宽广的检测范围为0.5μmol·L-1到70μmol·L-1.本文提出的适配体基的传感器有很好的重复性和稳定性,作为一个潜在的手段可以应用在生物分析和医疗诊断中.     

基于AuNPs/PANI/TNTs纳米复合材料的电化学检测妥布霉素的适配体传感器

本文提出了一种新型的检测妥布霉素的电化学适配体传感器,以差分脉冲伏安法（DPV）作为检测技术,亚甲基蓝作为电化学响应信号. 构建了以纳米复合材料金纳米粒子/聚苯胺/二氧化钛纳米管(AuNPs/PANI/TNTs)修饰玻碳电极的电极支架. 通过透射电子显微镜和X-射线光电子能谱对纳米复合材料进行详细的表征. 循环伏安图和电化学阻抗谱显示AuNPs/PANI/TNTs可以很好地增加电极的界面传导性能. DPV结果显示电流密度的响应和妥布霉素浓度之间存在一个很好的线性关系,并且得到一个宽广的检测范围为0.5 μmol·L^-1到70 μmol·L^-1. 本文提出的适配体基的传感器有很好的重复性和稳定性,作为一个潜在的手段可以应用在生物分析和医疗诊断中.     

基于纳米铁氰化镍修饰二氧化钛纳米管阵列电极的非酶葡萄糖传感器

以二氧化钛纳米管阵列(TNTs)为基底,利用脉冲电沉积的方法将Ni纳米粒子沉积在TNTs管内,通过循环伏安法将Ni转化为铁氰化镍(NiHCF),构造了新型的非酶型葡萄糖生物传感器(NiHCF/TNTs修饰电极)。在优化的实验条件下,传感电极的灵敏度为663μA/(mmol cm2);响应电流与葡萄糖浓度在1～23mmol/L范围内呈现良好的线性关系。在低浓度检测下,线性范围为2×10-3～1.0 mmol/L;检出限为0.5μmol/L。本传感电极具有灵敏度高、稳定性好和抗干扰能力强等特点。     

TiO2纳米管与纳米线的制备及光电化学研究

利用钛箔表面沉积一层TiO2纳米粒子作为晶种,与NaOH反应,通过改变反应温度制备了TiO2纳米管与纳米线.在170℃,48 h的条件下合成了TiO2纳米管.在180℃时得到另一种一维的TiO2纳米线.并用XRD,SEM,SAED,EDS及HRTEM等分析手段对两种产物的成分、形貌、结构进行表征.对TiO2纳米管电极的光电化学性能进行了研究.结果表明,TiO2纳米管与纳米线为锐钛矿型和金红石型的混晶结构.TiO2纳米管单色光的光电转化效率达到10.38%.与钛酸盐纳米管相比,混晶结构TiO2纳米管显示出优良的光电转化性能.     

复合方式对MWCNTs/TiO2纳米复合薄膜光电化学性能的影响

采用溶胶-凝胶法制备了不同复合方式的系列多壁碳纳米管(multi-walled carbon nanotubes.MWCNTs)/TiO2纳米复合薄膜电极.通过SEM表征了薄膜的表而形貌,并测定了MWCNTs引人前后对TiO2晶型结构和光吸收性能的影响以及不同复合方式的纳米复合薄膜的光电化学特性.结果表明,MWCNTs/TiO2纳米复合薄膜表面形成无序多孔的形貌,其光谱吸收边可拓展到可见光区;MWCNTs底层分布的纳米复合薄膜比纯TiO2表现出更好的光电活性,而MWCNTs在表层分布及均匀分布的纳米复合薄膜的光电活性相对较差.依据载流子分离原理探讨了不同复合方式对纳米复合薄膜光电性能的影响,底层分布MWCNTs的纳米复合薄膜由于MWCNTs有效地收集传递电子并阻止载流子的复合从而提高了光电化学活性.     

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%.     

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.     

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.     

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.     

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.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.