肿瘤热疗化疗联合治疗用温敏磁性复合粒子的磁热性能(英文)

采用无皂乳液聚合法制备了Fe3O4/P(N-异丙基丙烯酰胺-共-丙烯酰胺)[P(NIPAAm-co-Am)]温敏磁性复合粒子,分别采用透射电镜(TEM),振动磁强仪(VSM)和动态激光散射仪(DLS)对复合粒子进行表征,并着重研究了复合粒子在交变磁场作用下的磁热性能。结果表明,Fe3O4纳米粒子表面包裹了一层P(NIPAAm-co-Am)温敏性聚合物,其最低临界溶解温度(LCST)约为40℃,利用磁性粒子在交变磁场下的磁热性能可使复合粒子的温度升高至LCST以上,可触发复合粒子发生体积收缩。另外,复合粒子在交变磁场下的磁热性能可通过改变磁性粒子的浓度或调节磁场来调控。     

可控制自由基聚合DPE法制备P(AA-MMA-ST)/Fe3O4磁性复合微球

在制备超细Fe₃O₄磁性粒子的基础上, 利用可控制自由基聚合DPE法制备出平均粒径为265 nm的P(AA-MMA-ST)/Fe₃O₄磁性复合微球. 采用XRD, TGA, FTIR等手段对所制备的磁性复合微球的形态、结构及磁响应性等进行了表征, 结果表明用DPE法制备出的磁性复合微球磁含量较高, 粒径比较均匀.     

可控制自由基聚合DPE法制备P(AA-MMA-ST)/Fe3O4磁性复合微球

在制备超细Fe₃O₄磁性粒子的基础上, 利用可控制自由基聚合DPE法制备出平均粒径为265 nm的P(AA-MMA-ST)/Fe₃O₄磁性复合微球. 采用XRD, TGA, FTIR等手段对所制备的磁性复合微球的形态、结构及磁响应性等进行了表征, 结果表明用DPE法制备出的磁性复合微球磁含量较高, 粒径比较均匀.     

磁性高强度聚丙烯酰胺/Fe3O4纳米复合水凝胶

以辐射过氧化的表面活性剂胶束为引发中心和交联中心, 制得具有优异机械性能的聚丙烯酰胺(PAAm)水凝胶, 并通过原位化学共沉淀法向其中引入Fe₃O₄粒子, 得到了磁性复合水凝胶. 扫描电子显微镜(SEM)表征发现磁性粒子在凝胶中分布均匀, 其粒径约为30 nm. X射线衍射(XRD)表征证实所引入的纳米粒子为尖晶石型Fe₃O₄. 磁性能测试表明, PAAm/ Fe₃O₄复合水凝胶具有超顺磁性特征. 该复合凝胶具有较优异的机械性能, 其断裂伸长率可以达到1200%, 拉伸强度最大可达0.10 MPa. 另外, 该复合凝胶表现出良好的形变回复特性.     

多孔软硬磁Ni0.5Zn0.5Fe2O4/SrFe12O19复合纤维制备及吸波性能

通过静电纺丝技术制备了多孔软硬磁Ni_0.5Zn_0.5Fe₂O₄/SrFe₁₂O₁₉复合纤维,利用综合热重分析仪（TG-DSC）、X射线衍射仪（XRD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）、X射线能谱仪（EDS）和矢量网络分析仪（VNA）等对复合纤维的晶体结构、微观形貌和电磁性能进行了表征,研究了不同软硬磁质量比对纤维结构和性能的影响。结果表明：900℃下制备的复合纤维具有立体多孔结构,软硬磁质量比为1∶3时,复合纤维的比表面积达到55 m²·g^-1。吸波性能测试结果显示,当吸波剂涂层厚度为3.5 mm时,复合纤维在10.6 GHz处反射损失（R_L）值达到-31.9 dB,在2~18 GHz频率范围内,R_L值小于-10 dB的吸收带宽达到10.5 GHz,覆盖了整个X波段（8.2~12.4 GHz）和Ku波段（12.4~18 GHz）,显示出优异的宽波段吸收性能。     

表面图案化磁性复合微球的原位制备与表征

采用反相悬浮聚合法合成了丙烯酸(AA)含量不同的N-异丙基丙烯酰胺-丙烯酸共聚物P(NIPAM-co-AA)微凝胶, 并以其作为微反应器, 通过原位外源沉积法制备了一系列微米级、表面具有图案化结构的SiO₂-Fe₃O₄-P(NIPAM-co-AA)磁性复合微球. 实验结果表明, 复合微球的表面结构与微凝胶的组成、Fe₃O₄和SiO₂的沉积量有关. 在微球表面进行修饰, 可得到表面带有氨基等官能基团的磁性复合材料. 将这种功能化磁性微球用于识别生物大分子并进一步用于生物医学领域具有重要的意义.     

溶剂热法制备BiFeO3基纳米颗粒光催化剂及其性能

以聚酰胺-胺（PAMAM）树形分子为稳定剂,采用溶剂热法制得了纯相BiFeO₃纳米颗粒（A）和BiFeO₃/Bi₂₅FeO40/Fe₂O₃复合纳米颗粒（B）,并采用HRTEM、XRD、UV-Vis、SQUID对其结构和性能进行了表征。2种颗粒结晶良好,粒径小于10 nm,能有效光催化降解亚甲基蓝,磁性回收率分别为74.6%（A）和90.2%（B）。BiFeO₃/Bi₂₅FeO40/Fe₂O₃复合纳米颗粒的光催化与磁性能均优于纯相BiFeO₃纳米颗粒,是因为复合纳米颗粒含有多种相,相界面存在异质结构有利于光生载流子的分离和迁移,并且对可见光的吸收能力更强。     

Fe3O4@SiO2@polymer复合粒子的制备及在药物控制释放中的应用

本文通过多步反应制备了一种新型的、多层结构的、多功能的磁性纳米复合粒子, (Fe₃O₄@SiO₂@polymer). 纳米复合粒子内核是磁性Fe₃O₄纳米粒子, SiO₂包裹在Fe₃O₄上能够使其稳定分散和保护其不被腐蚀氧化; 中间层是生物相容的聚天冬氨酸(PAsp)载药层; 最外层是亲水的聚乙二醇(PEG)稳定层. 磁性纳米复合粒子各层都是生物相容的, 利用静电作用将抗癌药物阿霉素(DOX)负载在磁性纳米复合粒子中, 通过PAsp的pH响应调节了DOX的释放速率.     

Pd/Fe3O4-MCNT磁性催化剂的制备、表征及催化性能

利用多元醇法制备了单分散Fe₃O₄纳米粒子修饰多壁碳纳米管(MCNT)的磁性复合材料, 并以X射线衍射(XRD)、透射电镜(TEM)和X射线能量色散谱(EDS)对碳纳米管磁性复合材料的结构和组成进行了表征. 研究发现, 通过调控Fe₃O₄前驱体与MCNT载体的质量比, 可以很好地控制沉积的磁性纳米粒子大小. 以碳纳米管磁性复合材料为载体, 采用多元醇法成功制备了Pd负载量为3.0% (w)的Pd/Fe₃O₄-MCNT磁性催化剂. 磁性质测试表明碳纳米管磁性复合材料在负载Pd前后都具有良好的超顺磁性. 以肉桂醛加氢为探针反应研究了Pd/Fe₃O₄-MCNT的催化性能, 结果表明该催化剂表现出良好的催化加氢性能, 在外加磁场下催化剂能与液相反应体系高效分离, 循环使用4次后, 催化性能没有明显下降, 显示了良好的循环利用性能.     

棒状CuFe4Ox的可控合成及其异戊醇脱氢反应的催化性能

利用液相沉淀法可控合成了均匀的棒状CuFe₄O_x催化剂。通过原位X射线粉末衍射（XRD）、高分辨透射电子显微镜（TEM）及程序升温还原（TPR）等手段表征其晶相结构、形貌和还原性能。通过还原棒状CuFe₄O_x获得Cu⁰/Fe₃O₄ 纳米棒,原位X射线光电子能谱（XPS）用于确定Cu⁰/Fe₃O₄ 表面的相组成。通过液相沉淀法制备棒状CuFe₄O_x,在120℃保持3 h后加入Na₂CO₃溶液至pH等于9时所得棒状形貌最为规整。以异戊醇脱氢反应作为探针反应,比较了Cu⁰/Fe₃O₄ 纳米棒和Cu⁰/Fe₃O₄ 纳米颗粒的催化反应性能,发现Cu⁰/Fe₃O₄ 纳米棒比Cu⁰/Fe₃O₄ 纳米粒子具有更好的活性和稳定性,表明棒状Fe₃O₄ 担载的Cu纳米粒子具有更好的结构稳定性。     

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.