碳量子点/壳聚糖复合物的制备及用于槲皮素检测

以柠檬酸三钠、11-氨基十一烷、聚乙二醇400为碳源,利用微波法制备了碳量子点,将其与壳聚糖反应,制备出碳量子点/壳聚糖复合物。采用荧光、紫外、红外光谱等对碳量子点和碳量子点/壳聚糖复合物进行表征,探究了温度、时间、缓冲溶液及pH对体系荧光强度的影响。在pH 7.6的硼酸—硼砂缓冲介质中,槲皮素可使碳量子点/壳聚糖复合物发生荧光猝灭,其猝灭程度与槲皮素浓度呈良好的线性关系,据此建立了碳量子点/壳聚糖荧光猝灭法测定槲皮素的新方法,方法线性范围为4~40μmol/L,相关系数为0.9940,检出限为0.5μmol/L。方法已应用于测定本地甜瓜中槲皮素的含量。     

微波法制备氮掺杂碳点/海藻酸纳米复合物及其电沉积技术研究

以海藻酸为碳源,乙二胺为氮掺杂剂,采用简单方便的微波法制备得到氮掺杂碳点(N-CDs)/海藻酸纳米复合物.通过透射电镜观察到所制得的N-CDs/海藻酸纳米复合物有纳米粒子存在,它们的平均粒径为4.6 nm.荧光性能分析表明N-CDs/海藻酸纳米复合物在365 nm紫外光下呈现明显的蓝色荧光,并且其荧光发射性能具有激发光...     

光谱法研究CdSe/CdS/ZnS量子点与壳聚糖的复合

通过CdSe/CdS/ZnS量子点与壳聚糖之间的静电作用,用共混法制备了壳聚糖-CdSe/CdS/ZnS复合物.用荧光光谱、紫外-可见光谱、红外光谱对所得的壳聚糖-CdSe/CdS/ZnS复合物进行了表征.研究结果表明:壳聚糖-CdSe/CdS/ZnS复合物具有良好的光学性能.     

碳量子点标记的硼替佐米缓释制剂的合成与应用

硼替佐米的肽硼酸与壳聚糖的羟基发生酯化反应生成肽硼酸酯,即得到硼替佐米-壳聚糖复合物;然后,该复合物中壳聚糖的氨基与碳量子点表面羧基发生静电吸附作用,将碳量子点吸附进入壳聚糖体系内,进而得到硼替佐米-壳聚糖-碳量子点复合纳米粒载体.此产物具有生物相容性、无毒副作用、荧光示踪及pH敏感等性质,在生物传感、生物医用材料、功能纳米材料,尤其是药物载体或制剂的控制释放方面,具有重要的研究意义和应用价值.     

水相一步法合成具有双光子效应的高效橙红荧光聚合物碳点

聚合物碳纳米点是近年来新兴的一种荧光纳米探针,具有较低的生物毒性、良好的水溶性、较高的量子产率、优异的光/化学稳定性以及良好的生物相容性.目前所制备的碳点大都表现出蓝、绿色荧光发射.为实现碳点长波荧光发射,扩大其在生物标记与成像及光电显示方面的应用,本文采用水相一步法交联聚合反应制备了具有橙红荧光发射性质且具有双光子效应的聚合物碳点,发射波长为604 nm,荧光量子产率达到30.64%,并且应用在生物活体成像中.     

水溶性量子点的制备及其与壳聚糖衍生物的自组装

以3-巯基丙酸(HS-CH2CH2COOH)为稳定剂, 制备了水溶性的碲化镉(CdTe)量子点(QDs), 考察了制备条件对QDs荧光性能的影响及CdTe QDs与壳聚糖及叶酸和聚乙二醇改性的壳聚糖的自组装. 研究发现, 壳聚糖及改性壳聚糖与QDs的复合物荧光强度相对纯的CdTe QDs明显增强, 且QDs被包裹在内核, 复合粒子呈明显的核/壳结构. 改性壳聚糖/QDs复合物较小且尺寸分布更为均一.     

碳点/β-环糊精复合物的制备及其用于尿酸检测的研究

以柠檬酸三钠为碳源,采用微波辅助制备碳点,用β-环糊精(β-CD)和碳点复合制备出碳点/β-CD复合物,并用荧光、紫外、红外光谱等进行表征.在pH=6.6的磷酸盐缓冲溶液中,尿酸可使碳点/β-CD复合物的荧光增强,探讨了反应时间、反应温度、缓冲溶液及pH对荧光增强程度的影响,建立了测定尿样中尿酸含量的方法.碳点/β-C...     

碳点的制备及在荧光分析中的应用

综述了碳点的制备方法、碳源材料以及碳点在荧光分析中的应用(包括生物成像、生物分子检测和金属离子检测)。碳点的合成方法包括自上而下法(电弧放电法、激光消融法、电化学合成法和酸氧化法)及自下而上法(微波法、水热法和超声法),并对碳点的发展前景进行了展望(引用文献79篇)。     

采用一锅法制备量子点/琼脂纳米复合凝胶

以天然高分子琼脂为稳定剂,采用简单便捷的一锅法制备Mn掺杂ZnS量子点/琼脂纳米复合凝胶,琼脂不仅作为制备量子点的稳定剂,同时也是纳米复合凝胶的主要成分。对该纳米复合凝胶中量子点的化学结构和尺寸大小进行了表征,并对纳米复合凝胶的荧光性能和凝胶性能进行了研究。实验结果表明,制备得到的纳米复合凝胶均一稳定,在302 nm紫外光下呈现十分明显的橙红色荧光。在该纳米复合凝胶的透射电子显微镜（TEM）表征中可以观察到大小比较均一、粒径为3 nm左右的纳米粒子,光谱分析结果进一步证实纳米复合凝胶中存在Mn掺杂ZnS量子点。该纳米复合凝胶不仅具有良好的荧光性能,还具有温度刺激响应性可逆溶胶-凝胶转变性能,同时具有较高的溶胶转变温度和较好的温度稳定性。利用这些性能特点,可以方便地制备纳米复合凝胶小球。此外,该纳米复合凝胶还可以被潜在应用于金属离子的荧光检测分析领域。     

一锅法制备量子点/琼脂纳米复合凝胶

以天然高分子琼脂为稳定剂,采用简单便捷的一锅法制备Mn掺杂ZnS量子点/琼脂纳米复合凝胶,琼脂不仅作为制备量子点的稳定剂,同时也是纳米复合凝胶的主要成分。对该纳米复合凝胶中量子点的化学结构和尺寸大小进行了表征,并对纳米复合凝胶的荧光性能和凝胶性能进行了研究。结果表明,制备得到的纳米复合凝胶均一稳定,在302nm紫外光下呈现十分明显的橙红色荧光。TEM表征显示,在该纳米复合凝胶中可以观察到大小比较均一、粒径为3nm左右的纳米粒子;光谱分析结果进一步证实纳米复合凝胶中存在Mn掺杂ZnS量子点。该纳米复合凝胶不仅具有良好的荧光性能,还具有温度刺激响应性可逆溶胶-凝胶转变性能,同时具有较高的溶胶转变温度和较好的温度稳定性。利用这些性能特点,可以方便地制备纳米复合凝胶小球。此外,该纳米复合凝胶还有望应用于金属离子的荧光检测分析领域。     

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%.     

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.     

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.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.