双亲性无规共聚物P（VM-co-AMPS）的自组装及其性能

以2-丙烯酰胺基-2-甲基丙磺酸（AMPS）和苯乙烯类光敏单体7-（4-乙烯基苄氧基）-4-甲基香豆素（VM）为共聚单体,采用自由基聚合法制备了光敏性双亲共聚物P（VM-co-AMPS）。P（VM-co-AMPS）在溶剂水中自组装胶束化,用原子力显微镜（AFM）表征了自组装胶体粒子的形态、粒径及其分布。紫外光照使胶体粒子中香豆素基元发生光二聚反应,用紫外-可见光分光光度计（UV-Vis）跟踪其光二聚交联过程,用光学显微镜考察了胶体粒子的乳化性能。结果表明：胶体粒子具有较好的紫外吸收性能和较好的乳化性能。该胶束制备工艺简单,条件温和,避免了溶剂的使用。     

光敏性无规共聚物P(FA_2C-co-AA)的自组装及乳化性能

光敏性单体ε-己内酯改性丙烯酸酯肉桂酸酯(FA2C)与丙烯酸(AA)在偶氮二异丁腈(AIBN)的引发作用下,于N,N-二甲基甲酰胺(DMF)中发生自由基共聚反应,制备了具有光敏性的双亲无规共聚物P(FA2C-co-AA)。以红外光谱、凝胶渗透色谱、差示扫描量热和紫外光谱等分析测试手段对共聚产物进行了表征。P(FA2C-co-AA)在选择性溶剂DMF水溶液中自组装得到纳米粒径的胶体粒子。用紫外光引发胶体粒子内双键发生光交联反应,得到稳定的胶体粒子,并用动态激光光散射(DLS)表征了胶体粒子交联前后的粒径变化。结果表明:该胶体粒子具有良好的乳化性能。     

光敏共聚物P(St/VM-co-MA)自组装胶体粒子及其性能

以苯乙烯类光敏单体7-(4-乙烯基苄氧基)-4-甲基香豆素(VM)、苯乙烯(St)、马来酸酐(MA)为共聚单体,采用自由基聚合法制备了光敏性双亲共聚物P(St/VM-co-MA).在选择性溶剂(N,N-二甲基甲酰胺(DMF)/H2O)中对P(St/VM-co-MA)进行自组装,用透射电镜(TEM)和动态激光光散射(DLS)表征了自组装胶体粒子的形态、粒径大小及其分布.利用紫外光照使胶体粒子中香豆素基元发生光二聚反应,形成交联胶体粒子,并用紫外-可见光分光光度计(UV-Vis)跟踪其交联过程.用DLS研究了交联和未经交联胶体粒子的粒径和结构稳定性,用激光扫描共聚焦显微镜(LSCM)和光学显微镜考察了胶体粒子的乳化、包覆性能.结果表明:交联和未经交联胶体粒子均具有乳化性,且在乳化过程中可实现对油溶性染料的包覆.胶体粒子交联后,粒径有所减小,结构稳定性、乳化性能、包覆性能均有所提高.     

香豆素改性透明质酸颗粒乳化剂的制备及应用

利用7-(2-羟基乙氧基)-4-甲基香豆素(HEMC)疏水改性透明质酸(HA)制得光敏双亲大分子(HA-HEMC),并通过自组装形成了HA-HEMC胶体粒子。通过核磁共振氢谱和紫外分光光度计确定了HA-HEMC的结构及取代度;采用动态激光光散射、纳米粒度仪和透射电镜等手段对胶体粒子的性质及形貌进行了表征。进一步以HA-HEMC胶体粒子作为颗粒乳化剂稳定油水界面,研究了胶体粒子质量浓度、油相类型、水相pH和盐浓度对胶体粒子乳化性能的影响。结果表明:HA-HEMC可以在选择性溶剂中自组装形成粒径约为236nm的球形胶体粒子;该胶体粒子能够在较宽的pH范围内(3~11)稳定水包油型乳液且所得乳液有良好的耐盐性;此外,HAHEMC胶体粒子还能稳定多种油-水体系。     

紫外光引发Pickering乳液聚合制备中空复合微球的研究

用光引发剂2-羟基-4-(2-羟乙氧基)-2-甲基苯丙酮(IHT-PI 659)对纳米SiO₂表面进行接枝使之兼具两亲性及光引发特性|以该功能性纳米SiO₂为稳定剂构筑O/W(水包油)型Pickering乳液|用紫外光引发处于内油相的甲基丙烯酸甲酯单体聚合, 制备出具有中空结构的SiO₂/PMMA复合微球, 采用傅里叶变换红外光谱(FTIR)、热失重分析仪(TGA)、透射电镜(TEM)及扫描电子显微镜(SEM)对复合微球进行了表征, 并提出了紫外光引发Pickering乳液聚合制备中空复合微球的机理.     

Pickering乳液模板法制备Janus粒子

本文以SiO₂粒子稳定的水包油(O/W)型Pickering乳液作为模板, 在乳液连续相进行SI-ATRP, 将聚合物刷接枝到SiO₂粒子外半表面, 破乳得到半修饰的Janus粒子.     

Pickering乳液聚合制备核-壳结构PS-SiO2复合微球

用二氯二甲基硅烷对纳米SiO2粒子进行疏水改性,当其表面Zeta电位由-54.8 mV变成-25.8 mV时,SiO2粒子就能在苯乙烯-水界面自组装,形成稳定的Pickering乳液,即以胶体粒子为乳化剂的乳液.利用Pickering乳液聚合制备了以聚苯乙烯(PS)为核、纳米SiO2为壳的PS-SiO2复合微球.用FT-IR、XPS、SEM、偏光显微镜等对复合微球进行了表征.结果表明:复合微球由聚苯乙烯和纳米二氧化硅粒子组成,二氧化硅粒子以单层、六方密排的方式分布在聚苯乙烯微球表面.     

在无机SiO2纳米粒子存在下的苯丙乳液共聚合

研究了在无机SiO₂纳米粒子存在下的苯丙乳液共聚合.选择了能使苯丙乳液稳定存在的乳化剂体系,研究了温度和SiO₂的加入对聚合过程转化率的影响,结果表明,SiO₂的加入对聚合过程有阻聚作用,使单体的转化率降低.SEM照片证明SiO₂粒子已经进入苯丙乳液粒子中,而且SiO₂的加入对乳液制成的膜断面形态有一定影响.实验发现在无机SiO₂纳米粒子存在下,苯丙乳液共聚合时有较多残渣出现,对此通过改进乳液聚合进行了有效地改善.同时对制成的复合材料进行了力学性能和热学性能的测定.     

环糊精包结络合作用诱导的水溶性聚芴纳米粒子的制备

首先合成了单取代的β环糊精ATRP引发剂(β-CD-Br),利用核磁、质谱等对其进行了表征,并通过ATRP聚合制备了端基为β-环糊精的水溶性聚合物聚甲基丙烯酸N,N-二甲基氨基乙酯(β-CD-PDMAEMA).聚合物β-CD-PDMAEMA可以通过环糊精与金刚烷之间的主客体包结络合作用与端基为金刚烷的聚芴(PFADA)形成水溶性的聚芴纳米粒子.重点探讨了β-CD-PDMAEMA与PF-ADA的质量比和不同的组装方法对纳米粒子尺寸及分布的影响,研究表明质量比为4∶1时通过向2种聚合物的THF混合溶液中缓慢加水的方法可得到流体力学半径(R_h)为80 nm、PDI为0.11的纳米粒子.最后利用透射电子显微镜和原子力显微镜对纳米粒子的形貌进行了表征,进一步依照纳米粒子的R_h随温度升高的实验可以证实纳米粒子具有明显的核壳结构,其中刚性的聚芴为核半径约为50 nm,水溶性的PDMAEMA聚合物为壳.     

Pickering乳滴模板法制备超粒子结构有机/无机杂化微球

Pickering乳滴模板法制备有机/无机杂化的核壳微球越来越引起人们的关注,主要因为该方法制备出的微球具有以无机粒子为壳层的超粒子结构(supracolloidal structure),能够赋予微球独特的功能.胶体粒子在乳滴表面自组装形成有序的球面胶体壳,得到稳定Pickering乳液,固定乳滴表面的胶体粒子来制备核壳结构的微球或者以胶体粒子为壳层的微胶囊(colloidosome).本文综述了我们课题组以Pickering乳滴模板法制备超粒子结构有机/无机杂化微胶囊包括实心微球方面的工作.我们选择具有不同性能、种类的胶体粒子以及具有不同性质和功能的核材料,采用Pickering乳滴模板法,对吸附在乳滴表面的胶体粒子用不同的固定方法制备具有不同结构和性能的微球和微胶囊,利用基于多重Pickering乳液的聚合技术制备双纳米复合的超粒子结构多核聚合物微球.     

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.     

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.     

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.     

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.