二氧化钛反蛋白石薄膜的制备及其在化学传感器中的应用

用提拉成膜法将单分散295 nm聚甲基丙烯酸甲酯(PMMA)胶体微球自组装成蛋白石光子晶体膜. 在PMMA蛋白石光子晶体膜的空隙里填充15 nm二氧化钛纳米颗粒, 经500 ℃的处理除去PMMA膜板, 制备出大面积, 结构均一的二氧化钛反蛋白石光子晶体膜. 扫描电子显微镜(SEM)观察和X射线光电能谱(XPS)分析表明, 这种二氧化钛反蛋白石光子晶体薄膜是六方紧密堆积. 用这种二氧化钛反蛋白石光子晶体膜对溶液折射率的检测实验表明该传感膜分辨率可达0.01.     

三联噻吩衍生物功能化SiO2反蛋白石光子晶体荧光薄膜的制备及应用

将单分散聚苯乙烯微球乳液与SiO₂溶胶均匀混合后, 于恒温恒湿条件下, 竖直沉积共组装制备得到蛋白石型光子晶体薄膜, 然后利用牺牲模板法制得SiO₂反蛋白石光子晶体薄膜. 该薄膜依次经过浓硫酸与过氧化氢混合液、 3-氨丙基三甲氧基硅烷的甲苯溶液、 三联噻吩的三氯甲烷溶液和硼氢化钠的甲醇溶液处理后, 得到三联噻吩衍生物功能化的SiO₂反蛋白石光子晶体. 结果表明, 制备得到的光子晶体薄膜在512 nm处有荧光发射, 经紫外辐射后荧光猝灭, 甲醛气氛下458 nm处又出现新的荧光发射峰. 在甲醛气氛下20 s即可观察到荧光发射, 空气氛围下可恢复, 10次循环仍可保持强的荧光发射, 可重复性良好. 以无反蛋白石光子晶体结构的三联噻吩衍生物的平滑膜与甲醛作用的体系作为参比, 以330和400 nm聚苯乙烯微球为模板制备的三联噻吩功能化反蛋白石光子晶体, 在甲醛气氛中发射的荧光分别增强47.5和78.6倍. 这是由于光子晶体光子禁带的红带边和蓝带边与荧光发射波长相重叠, 产生了慢光子效应, 极大地增强了发射的荧光强度.     

二维胶体晶体异质结构的制备及传感性

制备具有不同粒径和折射率的聚苯乙烯(PS)和聚甲基丙烯酸甲酯(PMMA)微球,采用多次尖端导流法制备多重二维胶体晶体异质结构(2D-CCHs)阵列,在2D-CCHs阵列的间隙处填充丙烯酸类凝胶,再将PS或PMMA模板微球去掉,得到传质速度更快的2D-CCHs反蛋白石凝胶.经扫描电子显微镜证实,所制备的异质结构胶体晶体均为二维结构,且排列较为规整.德拜衍射、反射光谱和结构色分析结果表明,2D-CCHs的光学性质主要是各单层二维胶体晶体阵列独立衍射的叠加.随着p H值由7降低至3,双层2D-CCHs反蛋白石凝胶的德拜衍射环直径均减小了约80 nm,表明2D-CCHs反蛋白石凝胶可应用于化学传感领域.     

流动控制沉积法制备PMMA叠层光子晶体薄膜及其光学性能研究

采用流动控制沉积法, 通过调控泵速和聚甲基丙烯酸甲酯(PMMA)胶体微球溶液的浓度, 制备出微球排列高度有序且薄膜紧密附着于基底的高质量光子晶体薄膜. 获得了制备高质量PMMA光子晶体薄膜的组装条件范围, 发现在该条件范围内, 当泵速或胶体微球溶液浓度一定时, PMMA光子晶体薄膜的厚度随胶体微球溶液浓度的增加或泵速的降低而增加. 研究了组装条件对PMMA光子晶体薄膜光学性能的影响, 发现光子禁带位置随光子晶体薄膜厚度增加或减少而红移或蓝移. 在此基础上, 控制组装条件得到了不同尺寸微球堆叠而成的叠层光子晶体薄膜, 并研究了其光学性能的变化规律. 结果显示, 叠层光子晶体薄膜的光子禁带峰为各层叠层光子晶体禁带峰的简单叠加, 且峰强度受光入射角方向影响.     

聚苯乙烯光子晶体高效制备

以苯乙烯单体为原料,采用一步聚合自组装法制备了具有蛋白石结构的聚苯乙烯(PS)光子晶体(1);以1为模板制备了反蛋白石结构的TiO2光子晶体(2)来验证1的有序性;探讨了1的制备机理。1和2的结构和形貌经IR,SEM和TEM表征。讨论了乳化剂SDS的用量对PS微球排列有序性的影响。结果表明,SDS用量在30 mg～74 mg时,PS微球的粒径不断减小,微球排列的有序性受到影响;当SDS用量为52 mg时,PS微球排列的有序性最佳,能够形成蛋白石结构的1;2在大范围内有序排列进一步证明了1的高度有序性。     

反蛋白石光子晶体凝胶的pH响应

首先采用Stber方法制备了一系列亚微米级单分散二氧化硅小球,而后通过垂直沉降自组装方法制备了颜色鲜艳的二氧化硅三维有序结构胶体晶体模板,最后再采用模板聚合法在220 nm二氧化硅小球自组装的阵列间隙中共聚甲基丙烯酸和乙二醇二甲基丙烯酸酯,经氢氟酸刻蚀二氧化硅模板后得到多孔有序的反蛋白石光子晶体.当pH值从5升至8时,反蛋白石凝胶光子晶体的反射峰波长从514 nm移动至590 nm,颜色变化显著,从蓝绿色变成红色,突变点为pH=6.5,而且pH响应在100 s左右即可达到平衡.对交联剂用量的研究结果表明,随着交联剂乙二醇二甲基丙烯酸酯用量从4%增加到16%,光子晶体响应pH时的红移量减小.     

漂浮法制备SiO2有序大孔材料

用漂浮组装方法以亚微米尺度单分散的聚苯乙烯(PS)微球作为模板, 在悬浮液气-液界面处组装PS模板微球与纳米级胶体颗粒, 形成二元胶体颗粒共混物, 再去除模板得到有序大孔材料.     

硫化镉反蛋白石光子晶体制备及光解水制氢

对硫化镉反蛋白石结构光子晶体薄膜进行了可控合成,用巯基乙酸修饰的纳米晶和P(St-MMA-SPMAP)高分子小球共组装,成功地构筑了反蛋白石结构并用于可见光光解水产氢。结果表明,在可见光(λ≥420 nm)照射下,Cd S-310反蛋白石结构薄膜的光解水产氢性能比硫化镉纳米颗粒提高了一倍。这主要是因为等级孔结构反蛋白石光子晶体特性对催化剂的光催化性能的提升:首先,反蛋白石的周期性结构增加了光子在材料中的传播,提高了催化剂对太阳光的利用率;同时,大孔孔壁是由纳米颗粒堆积而成的,在反应中提供了更多的反应活性位点;此外,孔结构有利于物质的传输和分子的吸附。     

一种可精确控制粒径的SiO2微球合成方法

用改进的种子法合成SiO2微球. 微球生长过程中连续缓慢添加正硅酸乙酯,使用动态光散射法实时监控微球粒径的增长过程,调节正硅酸乙酯的添加,实现对粒径的精确控制. 为制备禁带位置位于1000 nm 的光子晶体,合成粒径为446 nm的SiO2微球,微球粒径在4 h内从193 nm 增长到446 nm,远远快于传统种子法,微球粒径与目标粒径偏差为±5 nm. 制得的SiO2微球被组装为光子晶体,其禁带位置恰好位于1000 nm.     

采用微流注射法在光纤端面制备单层胶体微球薄膜

提出了一种在光纤端面制备单层胶体晶体薄膜的新方法——微流注射法,利用针尖微量注射胶体微球溶液,该方法可以在气/液界面直接形成大面积六角密排的周期纳米球阵列,面积达到平方厘米级别,再利用二维胶体单层膜的可转移性,将薄膜转移至到光纤端面衬底上,形成单层胶体微球有序薄膜.采用扫描电子显微镜和光谱分析仪对样品形貌、结构以及光学特性进行了表征和分析.电子显微镜图像表明,光纤端面的胶体晶体为六角密排阵列结构.透射光谱表明,该结构具有光子晶体的带隙特征,带隙的中心波长约为700和850 nm,与分析软件FDTD Solutions仿真结果相吻合.结合溅射沉积方法,得到了银纳米球壳阵列结构,检验了其局域表面等离子体共振效应(LSPR).对比讨论了溶液浓度、弯月面的形成及注射速度等因素对微流组装胶体微球薄膜质量的影响.     

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.     

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.     

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.     

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.