磁性印迹纳米粒子固定血红蛋白修饰磁性电极构建过氧化氢传感器

采用表面印迹技术,以磁性二氧化硅纳米粒子（Fe₃O₄@SiO₂ NPs）作为载体、血红蛋白（Hb）为模板分子、正硅酸乙酯（TEOS）为印迹聚合物单体,制备了Hb印迹Fe₃O₄@SiO₂的磁性印迹纳米粒子（MMIPs NPs）. MMIPs NPs具有磁性内核和血红蛋白印迹壳层的核壳结构,可以富集并固定Hb. 使用壳聚糖将MMIPs NPs固定于磁性电极表面,构建血红蛋白类酶生物传感器,研究了Hb对过氧化氢（H₂O₂）的催化活性. MMIPS NPS相比于磁性非印迹纳米粒子（MNIPS NPS）,催化电流增加了14.3%. 采用磁性电极,MMIPS NPS、Hb和O₂的顺磁性使得该类酶生物传感器对H₂O₂的催化电流增加了60.0%. 血红蛋白类酶生物传感器电流响应与H₂O₂浓度在25 ~ 200 μmol·L^-1间呈线性关系,检出限为3 μmol·L^-1（S/N=3）,表明该类酶传感器对H₂O₂具有良好的催化性能.     

基于金纳米粒子及石墨烯量子点的四环素分子印迹电化学传感器研究

该文以四环素为模板分子,4-氨基苯硫酚(4-ATP)为功能单体,采用循环伏安法在金纳米粒子和石墨烯量子点复合材料修饰的玻碳电极表面电聚合分子印迹膜,制备四环素(TC)分子印迹传感器(MIPs/GQDs-AuNPs/GCE),并通过循环伏安法(CV)、电化学交流阻抗法(EIS)和线性扫描伏安法(LSV)等研究了其电化学响应性能。结果表明,该传感器对四环素具有良好的电流响应。在最佳实验条件下,TC氧化峰电流值与其浓度在2.0×10~(-8)～3.0×10~(-5) mol/L范围内呈良好的线性关系,相关系数为0.999 4,检出限为1.5×10~(-9) mol/L,加标回收率为97.9%～106%。该传感器稳定性好、响应灵敏、选择性高,具有良好的应用前景。     

胶态磁组装分子印迹光子晶体及其对L-苯丙氨酸的响应性

将胶态磁组装光子晶体与分子印迹技术结合, 通过磁场诱导快速、 可逆地组装得到一种灵敏度高、 选择性强且响应速度快的胶态磁组装分子印迹光子晶体(CMA-MIPCs), 并将其用于L-苯丙氨酸(L-Phe)分子的响应性研究. 结果表明, 细乳液聚合法制得的L-Phe磁性分子印迹纳米粒子(MMIPs)具有规则的球形形貌和明显的核-壳结构, 平均粒径为104.3 nm. CMA-MIPCs对L-Phe分子的识别可直接通过光学信号进行表达, 当L-Phe的浓度从6.0×10^-7 mol/L增加至6.0×10^-4 mol/L时, CMA-MIPCs的衍射色发生从紫色到深黄色的明显变化, 最大衍射峰位置红移181 nm, 响应过程仅需1 min. CMA-MIPCs对L-Phe的结构类似物L-酪氨酸(L-Tyr)和L-色氨酸(L-Trp)均无响应性, 表明CMA-MIPCs具有良好的选择性.     

复合纳米粒子修饰的柔性分子印迹传感器对四环素的检测研究

本文以酸化碳布(CC)作为柔性工作电极,采用恒电位沉积法在碳布上修饰纳米Au-Cu复合粒子(Au-Cu NPs),以四环素(TC)为模板分子,邻苯二胺为功能单体,采用循环伏安法在修饰了纳米粒子的活化碳布上电聚合分子印迹膜,制备了四环素分子印迹柔性传感器(Cu-Au NPs/PANI/TC/CC),通过循环伏安法(CV)、差分脉冲伏安法(DPV)研究了其电化学性能。结果显示,在优化实验条件下,TC的DPV峰值电流与其浓度在1.0×10~(-7)～3.0×10~(-5) mol/L范围内成良好的线性关系,相关系数为0.9996,检出限为2.57×10~(-11) mol/L,实际样品的加标回收率为97.3%～105%。该传感器柔软稳定,灵敏度高,抗干扰性和重复性好,可应用于柔性可穿戴传感器的设计。     

基于磁性分子印迹聚合物的电化学传感器的研究进展

分子印迹聚合物与磁性纳米材料结合,制备成磁性分子印迹纳米敏感膜,这样做不仅可以发挥分子印迹聚合材料的优势,而且磁性纳米粒子可有效提高电化学传感器的灵敏度、稳定性以及生物相容性等。近年来将磁性分子印迹纳米敏感膜应用于电化学传感器制备成的磁性分子印迹电化学传感器得到了较快的发展。本文就近5年来磁性分子印迹电化学传感器敏感膜所用的磁性材料、敏感膜制备方法以及磁性分子印迹电化学传感器在环境、食品以及临床方面的应用进行了综述总结。     

磁性分子印迹电化学传感法检测痕量奥卡西平

该文以4-乙烯基吡啶和甲基丙烯酸酯为原料制备了一种可用于检测奥卡西平（OXC）的磁性分子印迹 电化学传感器（MNPs－MIP/MCPE）。首先,依据密度泛函数理论（DFT/B3LYP/6－31 + G）计算,实验成功地 筛选和构建出 OXC与功能单体的最佳组合及比例。随后,基于沉淀聚合法合成了能够识别 OXC的磁性分子 印迹膜（MNPs－MIP）,将MNPs－MIP覆于碳糊电极（MCPE）表面制成MNPs－MIP/MCPE。采用差分脉冲伏安 法（DPV）将 MNPs－MIP/MCPE 传感器用于不同浓度 OXC 的测定。结果显示,传感器的峰电流信号随 OXC 浓 度的增大而增大,且OXC分别在5 × 10－8 ～3 × 10－6 mol/L和3 × 10－6 ～1. 5 × 10－4 mol/L浓度范围内与其峰电流 信号呈线性关系,其线性方程分别为：Ip （μA）= 1. 755 + 1. 097c（μmol/L）,相关系数（r）= 0. 999 7 和 Ip （μA）= 0. 131 + 5. 177c（μmol/L）,r = 0. 999 6。OXC的检出限（LOD = 3S/m）为2. 06 × 10－8 mol/L。该传感器成 功用于实际样品中OXC含量的检测,其回收率为99. 4%~101%,相对标准偏差（RSD）为1. 5%～2. 5%。     

表面分子印迹磁性纳米粒子的制备及其血红蛋白传感应用

以Fe₃O₄磁性纳米粒子为载体、多巴胺（DA）为功能单体、血红蛋白（Hb）为模板分子,用氯铂酸氧化DA生成聚多巴胺（PDA）,同时氯铂酸还原为铂纳米粒子（PtNPs）,与Hb一起负载于Fe₃O₄纳米粒子表面,洗脱Hb后合成了表面分子印迹磁性纳米粒子（印迹Fe₃O₄/PDA-PtNPs）. 将印迹Fe₃O₄/PDA-PtNPs修饰于磁性玻碳基底表面,制得印迹Fe₃O₄/PDA-PtNPs修饰电极. 实验结果表明,印迹Fe₃O₄/PDA-PtNPs具有良好的水溶性,粒径分布均匀,生成的PtNPs具有良好的导电性和刚性. 用印迹Fe₃O₄/PDA-PtNPs构建的传感器对Hb具有良好的识别性,在0.14 ~ 2.7 μg·mL^-1 Hb浓度范围与交流阻抗变化值呈良好的线性关系,检出限（S/N=3）为0.05 μg·mL^-1.     

基于Fe3O4@Ag壳核结构磁性纳米复合物的对杀螟硫磷的电化学传感

制备一种壳核结构的Fe3O4@Ag磁性纳米粒子,将该纳米粒子通过壳聚糖（CS）修饰在玻碳电极（GCE）表面,制备了对杀螟硫磷有灵敏电化学传感的Fe3O4@Ag/CS/GCE。应用透射电镜（TEM）和紫外可见光谱（UV-VIS）,对Fe3O4@Ag纳米粒子进行表征。运用电化学交流阻抗（EIS）、循环伏安法（CV）和时间电流法（I-T）来研究杀螟硫磷电化学特性。研究发现,在1.74×10-7～3.27×10–4 mol/L浓度范围内,该传感器可以实现对杀螟硫磷的快速检测,检测限为5.7×10-8 mol/L（S/N=3）     

胶体晶体

简要综述胶体晶体的研究进展情况,主要介绍胶体粒子的简单自组装、模板引导下的自组装和二元胶体晶体组装等几类主要的胶体晶体制备技术,并概述胶体晶体在光子晶体、传感器、光子纸张、三维有序大孔材料、二维纳米结构阵列等方面的应用。     

磁性粒子表面自组装辛可宁分子印迹电致化学发光传感器

以辛可宁为模板分子、十二烷基硫醇为功能单体,在Fe3 O4@Au纳米粒子表面自组装辛可宁分子印迹膜,构建了新型磁性粒子-分子印迹电化学发光传感器。通过透射电子显微镜对磁性纳米粒子的粒径分布及形貌进行了表征,使用红外光谱对比分析了辛可宁、分子印迹膜洗脱前和洗脱后的结构及成分。结果表明,在最优的实验条件下(0.012 mol/L 硼砂缓冲溶液(pH 9.5),0.8 mmol/L Ru(bpy)2+3),辛可宁浓度的对数在1×10-10~9×10-8 mol/L范围内,与电化学发光强度变化值有良好的线性关系,检出限为3.5×10-11 mol/L。此传感器灵敏度高、选择性好、易于更新,将其用于血清样品的检测,方法回收率为98.8%~104.7%。     

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%.     

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.     

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.     

Copper catalyzed/mediated synthetic methodology for ebselen and related isoselenazolones

Scope of the copper catalyzed/mediated selenium-nitrogen coupling reaction has been studied for the synthesis of isoselenazolones. It is noticed that the 2-chloro, 2-bromo-, and 2-iodo-aryl amides substrates can be exploited in the selenium-nitrogen coupling reaction by employing 25-100 mol % of CuI/1,10-phenanthroline (L) and potassium carbonate as a base in DMF. Furthermore, electron rich 2-chloro-arylamides also underwent selenium-nitrogen coupling reaction to give biologically important selenium-nitrogen heterocycles. Also, copper-catalyzed selenium-nitrogen coupling reaction has been meticulously applied for the synthesis of diaryl diselenides having methoxy, amine, and amide functionality from respective aryl iodides in the presence of stoichiometric amount of succinimide as an external Se-N coupling partner.     

Knoevenagel condensation catalyzed by novel Nmm-based ionic liquids in water

A series of novel N-methyl morpholine (Nmm) based ionic liquids with 1,2-propanediol group were synthesized and used as catalysts for Knoevenagel condensation at room temperature in water. Under the effect of the catalyst, various aldehydes or aliphatic ketones could react with a wide range of activated methylene compounds well, including malononitrile, alkyl cyanoacetate, cyanoacetamide, β-diketone, barbituric acid, 2-arylacetonitrile and thiazolidinedione. Furthermore, most of the products could be separated just by filtrating and washing with water. Additionally, the catalyst is recyclable and applicable for the large-scale synthesis.     

Construction of polyheterocyclic spirotetrahydrothiophene derivatives via sulfa-Michael/aldol cascade reaction

A series of polyheterocyclic spirotetrahydrothiophene derivatives were obtained in moderate to excellent yields via a catalyst-free sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 under mild conditions. We also present the first asymmetric sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 with moderate to good enantioselectivities catalyzed by readily available chiral phase-transfer catalysts (PTCs).     

Suzuki-Miyaura reactions of the soluble guanylate cyclase inhibitor NS2028: a non-product specific route to C-8 substituted analogues

Both soluble guanylate cyclase (sGC) inhibitors ODQ 1 and NS2028 2 are synthesized via improved protocols. In the former case treating 3,4-dihydroquinoxalin-2(1H)-one oxime 8, which can be prepared in two steps from 1,2-benzenediamine, with 1,1′-carbonyldiimidazole (CDI) gives the dihydro-ODQ 10 that in the presence of KMnO₄ oxidises to give ODQ 1 in an overall yield of 46% starting from 1,2-benzenediamine. In the latter case, the synthesis affords NS2028 2 from 2-amino-4-bromophenol 3 in three steps with an overall yield of 85% and avoids the need for chromatography. Furthermore, Suzuki-Miyaura reaction conditions are described that enable the preparation of 8-aryl and 8-heteroaryl derivatives of NS2028 directly from NS2028 2. Finally, demethylation of the 8-(methoxyphenyl) substituted analogues afforded the 8-(hydroxyphenyl) derivatives 40-42. All new products are fully characterised.