三维有序大孔炭的设计构筑、性能及应用研究

多孔炭材料具有高的比表面积、发达的孔结构、耐热、耐腐蚀、无毒无害、价廉、易操作等特点,以其为研究核心,在学术界和工业界均具有广阔的应用前景。通过胶晶模板法合成孔径在亚微米范围内的三维有序大孔炭,其高度规整的孔道结构,在吸附分离、催化和电极等领域已展现出巨大的应用潜能。利用双模板法将介孔结构融汇于三维有序大孔炭的孔壁中,设计构筑出三维有序大孔-介孔炭,势必会显著增强其应用价值。本文主要阐述了以胶晶为主体模板制备三维有序大孔炭的各种路径;采用双模板法将介孔引入大孔通道内获取三维有序大孔-介孔炭;探索影响孔结构参数的主要因素,并与各种功能材料复合增强其性能;着重对三维有序大孔炭及大孔-介孔炭在环境净化和新型能源转化与储备领域的应用进行概述。     

有序介孔材料与石墨化纳米点的自嵌入超组装

正近二十年以来,介孔材料已发展成为多孔材料的最重要领域之一~(1-3)。由于其具有高的比表面积、纳米尺寸的规整孔结构、丰富可调的骨架组成和表面性质,介孔材料为实现大分子的扩散与转化、能量的高效利用与储存等提供了难得的机遇和广阔的空间,并在电池、光伏、光电子、流体器件、传感器、离子交换、药物传送和催化领域有着广阔的应用前景~(4-6)。其中,通过在介孔材料的孔道或孔墙内部引入具有不同特性的客体材     

(MCM-41)-La_2O_3纳米复合材料的制备、表征及光学性质

借助水热法,以正硅酸乙酯为硅源,十六烷基三甲基溴化铵为模板剂,在碱性条件下制备了纳米MCM-41分子筛。通过固相热扩散法将La2O3组装到MCM-41介孔孔道中,制备出含La2O3不同浓度的(MCM-41)-La2O3主-客体纳米复合材料。采用化学分析、粉末XRD、FTIR、77K低温N2吸附-解吸附、固体扩散漫反射吸收光谱、拉曼光谱、扫描电镜和发光光谱对主-客体复合材料进行表征。粉末XRD结果表明,La2O3组装到MCM-41分子筛的孔道后并未破坏分子筛骨架,在所制备的(MCM-41)-La2O3主-客体纳米复合材料中MCM-41骨架结构仍然具有较高的有序性,并且,随着植入客体材料浓度的增加复合材料的有序度有所降低。红外光谱表明所制备的纳米复合材料主体分子筛骨架完好;低温氮气吸附-解吸附技术表明La2O3已经部分地占据了MCM-41分子筛孔道,导致分子筛的比表面积和孔体积都有所降低;固体扩散漫反射吸收光谱表明吸收光谱的吸收峰发生了蓝移现象,并表现出量子限域效应,说明La2O3已经组装到了MCM-41分子筛的孔道中;拉曼光谱表明所制备的复合材料没有出现新的特征峰,表明La2O3已经组装到了MCM-41分子筛的孔道中;扫描电镜表明(MCM-41)-La2O3样品的外观非常规整,主要呈现的是球状结构,La2O3含量为10%时,(MCM-41)-La2O3的平均粒径为(114±10)nm。发光光谱研究结果表明,所制备的复合材料(MCM-41)-La2O3样品在396nm处具有较好的发光性质,因而具有作为发光材料潜在应用前景。     

两亲性嵌段共聚物导向合成有序介孔金属氧化物半导体材料

有序介孔材料作为一种结构稳定、高比表面积、孔径可调、孔壁易于修饰的新型纳米结构材料在基础研究与应用开发方面都引起了人们的关注.有关有序介孔材料的文献中,无定型介孔材料(如二氧化硅、碳材料等)报道占据了大约70%,主要是由于传统软模板剂(如小分子表面活性剂或者聚环氧乙烷-b-聚环氧丙烷基嵌段共聚物)能够胜任无定型介孔材料的合成.相比而言,常规软模板剂在合成具有独特物化性能(光、电、磁以及催化、气敏等特性)的晶态半导体金属氧化物介孔材料方面面临很大的挑战.近年来,随着学科交叉发展以及高分子界研究人员加入无机多孔材料领域,一系列新型嵌段共聚物模板剂(例如具有高残碳率、高玻璃化转变温度和络合能力的嵌段共聚物)相继被合成并用于合成新型多孔材料,特别是这些模板剂在诱导组装合成有序介孔金属氧化物材料方面的研究取得了突出进展.本文从聚合物模板剂的制备与组装出发,围绕金属氧化物前驱体与模板剂之间的相互作用,系统综述了两者组装的作用机理和组装行为.深入探讨并总结了常见的三大组装方式:金属无机盐-聚合物模板、金属簇化合物-聚合物模板、金属纳米晶-聚合物模板组装,详细阐述了聚合物模板在合成有序介孔金属氧化物中的组装机理以及微观结构调控规律,并分析了聚合物模板诱导合成有序介孔金属氧化物未来宏量制备面临的机遇与挑战.鉴于其丰富的物化特性和新颖的介孔结构,有序介孔金属氧化物将逐步成为纳米光电器件、纳米催化载体以及化学传感的核心材料.     

有序介孔材料:历史、现状与发展趋势

有序介孔材料是指孔径在2~50 nm之间的多孔材料, 是一类具有均匀孔径、 高有序度纳米孔道和高比表面积的新材料. 在过去30年里, 有序介孔材料的研究取得了长足的进步, 在可控合成、 结构设计和调控及功能化等方面形成了系统的理论. 同时, 其应用领域也不断被拓展, 包括能源存储与转化、 催化、 生物医药和传感等方面. 本文首先回顾了有序介孔材料的发展历史, 简要介绍发展过程中“里程碑式”的研究工作; 然后根据构效关系总结了其在不同领域应用的最新进展; 最后讨论了有序介孔材料领域进一步发展所面临的挑战与机遇, 并对未来前景进行了展望.     

Eu(TTA)_3/MCM-41介孔复合体的溶胶凝胶法组装

利用溶胶 凝胶法将稀土配合物Eu(TTA) 3 组装到MCM 41介孔分子筛的孔道中 ,并初步认定客体分子Eu(TTA) 3 是以加合物形式包裹于表面活性剂胶束中。该法制得的介孔复合体Eu(TTA) 3/MCM 41,用XRD、HRTEM技术证实具有短程有序的、规整的六方介孔结构和大小分布均匀的纳米晶粒。对其光致发光和荧光寿命的研究发现 :与乙醇溶液中相比 ,Eu3 的荧光寿命没有发生改变 ,但Stokes位移却明显增大 ;复合体中 ,能量是从主体MCM 41传递到客体Eu(TTA) 3 上。     

(SBA-15)-ZnS主-客体纳米复合材料的制备与表征

本研究在SBA-15分子筛孔道中制备了纳米ZnS。Zn_{2+首先通过离子交换交换到SBA-15中,通过水热法在SBA-15分子筛孔道中制备了纳米ZnS。(SBA-15)-ZnS复合物由粉末X-线衍射,傅立叶变换红外光谱,低温氮气吸附-解析附技术,固体扩散漫反射光谱以及发光研究进行了表征。粉末X-线衍射研究说明在制备主-客体纳米复合材料中分子筛骨架未被制备过程所破坏,保持完整且结晶度仍很高。傅立叶变换红外光谱表明制备的材料骨架完好。77 K低温氮气吸附-解析附研究表明所制备的复合材料孔体积,孔尺寸以及表面积相对于SBA-15分子筛降低,证明客体ZnS已成功地组装入分子筛孔道中。所制备的纳米复合材料固体扩散漫反射吸收光谱相对于体相ZnS显示出蓝移表明,ZnS已限制在分子筛的孔道中且复合材料中分子筛的孔道对ZnS具有明显的立体限域效应,ZnS成功地组装在SBA-15分子筛的孔道中。发光研究表明,(SBA-15)-ZnS样品出现明显发光现象。主-客体复合材料具有良好的发光性能,有望在发光材料领域中获得应用。}     

大孔道介孔氧化硅/碳基纳米材料的设计合成与应用

由于具有较大的孔道尺寸、 丰富的化学组成以及广阔的应用前景, 大孔道介孔纳米材料近年来引起了科研工作者的广泛关注. 分别利用复合胶束和无机纳米晶作为结构基元进行可控自组装的软模板法和硬模板法是合成这类大孔道介孔纳米材料最有效的两类方法. 本文总结了一系列基于不同类型软模板或硬模板共组装形成大孔道介孔纳米材料的合成方法和策略, 并讨论了所获得的大孔道介孔纳米材料在催化、 能量转换与存储以及生物医学中的应用. 最后, 对利用新型嵌段聚合物或复杂结构纳米晶合成大孔道介孔纳米材料的前景和挑战进行了展望.     

介孔金属氧化物催化剂的合成与快速开发

介孔金属氧化物以其独特的高度有序介孔结构和化学物理特性,在化学、燃料和石油化工等领域有极大的应用前景,越来越受到人们的关注。本文介绍一系列简单通用的介孔金属氧化物纳米组装合成方法,以及基于此类方法,通过调节介孔材料的氧化还原性、酸碱性和半导体性质,可实现对催化剂催化性能的优化。同时,还重点介绍高精印刷技术与纳米组装合成相结合的复合介孔金属氧化物合成方法,并展望了介孔金属氧化物催化剂的未来发展趋势。     

镁热还原法制备有序介孔Si/C锂离子电池负极材料及其电化学性能

以SBA-15为前驱体,在660 ℃下通过镁热还原反应得到介孔硅材料,并对其进行碳包覆处理,成功地制备了有序介孔Si/C（OMP-Si/C）复合材料。该OMP-Si/C材料保留了SBA-15模板的有序蜂窝孔道,并且形成具有高堆积密度的莲藕链束结构。文中还提出了一个SBA-15镁热还原液态环境反应模型,探讨了660 ℃下硅的高度有序介孔与莲藕链束结构的形成机理。利用X射线衍射（XRD）仪、扫描电子显微镜（SEM）、透射电子显微镜（TEM）、氮气吸脱附法及拉曼光谱对样品物相和微观形貌进行了表征。这种高度有序介孔Si/C复合材料具有优异的电化学性能,展现出其在第二代锂电池负极材料领域中的潜在应用价值。     

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.     

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.     

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.