多孔聚合物的纳米形貌设计与多功能集成研究进展

多孔聚合物因具有独特的结构优势,如比表面积高、孔结构可控、密度低、表面与骨架化学环境易剪裁等,在气体存储、催化、传感、药物传递和分离等应用方面表现出优异的性能,受到了广泛关注。近年来,各种新型多孔聚合物已成为材料和化学研究领域的"新宠"。然而,孔结构精确调控、纳米形貌可控构筑以及功能组分的定制与集成,依然是多孔聚合物设计制备与应用所面临的难点与挑战。中山大学吴丁财教授团队在新型多孔聚合物的设计制备与应用方面开展了一系列研究工作,取得了重要进展。本文对他们研究工作的最新进展作了简要的评述。     

纳米零价铁在水相反应中的表面化学和晶相转化

纳米零价铁在水相中的表面化学特性和晶相等性质变化,将影响其反应活性及环境归趋等.总结近期课题组关于纳米零价铁在水相中表面化学和晶相转化的研究进展,为纳米零价铁污染控制化学提供基础理论.重点探讨水中有无溶解氧、不同水力学条件复氧（静态和扰动）、重金属共存、无机阴离子共存对纳米零价铁颗粒表面化学特性和晶相转变的影响.同时也研究高分子电解质表面修饰后,颗粒在水相中表面及晶相的演变及对重金属去除性能的影响.研究表明,纳米零价铁与水相中的水分子、溶解氧、重金属离子及无机阴离子反应,零价铁失去电子演变为氧化铁、羟基氧化铁等;环境条件对颗粒结构性能产生影响,从而影响污染物去除效率及其在环境中的归趋.未来研究将重点探讨结构性能动态变化与不同污染物之间反应性能的影响,建立纳米颗粒的结构与性能之间关系模型,为纳米零价铁材料的环境应用提供理论依据.     

磷酸钙纳米结构材料的微波辅助液相合成

微波加热作为一种新兴热源具有加热速率快、制备时间短、节能等优点,已经被广泛应用于合成包括磷酸钙在内的多种无机纳米材料.磷酸钙作为典型的生物材料,其制备新方法的探索、结构/尺寸/形貌调控、性能研究和应用探索是生物材料领域的一个重要研究方向.本文阐述了微波辅助合成法用于制备纳米材料的优势,并综述了微波辅助液相快速合成磷酸钙纳米结构材料的进展.采用微波液相合成技术,可以制备出包括颗粒、一维、二维和三维结构在内的多种磷酸钙纳米结构材料,同时还可以通过功能性组分的掺杂/复合对磷酸钙纳米材料进行功能化.预期未来微波液相合成法在包括磷酸钙在内的多种无机纳米材料的合成领域将得到快速发展和广泛应用;另外,微波液相合成的磷酸钙纳米结构材料在药物递送和控释、蛋白吸附、金属离子吸附、生物成像及骨缺损修复等众多领域具有良好的应用前景.     

人工控制液相金属纳米粒子的组装

液相中金属纳米粒子或团簇粒子的研究是现代化学和物理学的一个重要方面, 是对气相和真空中纳米粒子研究的补充。由于受到介质的强烈影响, 体系更为复杂, 然而却有了人工控制纳米粒子的大小和结构的可能性。本文介绍利用电离辐射或光化学方法还原金属离子在液相中制备金属纳米粒子, 通过调节介质的组成及介质的性质(如pH 值等) ,可以有效地控制其颗粒度大小, 并有可能最终控制纳米粒子的结构。该方法还具有颗粒度分布均匀、无须添加化学还原剂以及可以制备纳米合金粒子等优点。利用脉冲式辐照(脉冲辐解技术) 可以对液相中金属纳米粒子形成的化学反应机理进行深入的基础研究。     

合成介孔纳米晶体氧化锆的新方法(英文)

通过一种新颖的方法,即软模板-固液技术(CSSL)合成具有高比表面积的介孔纳米晶体氧化锆.首先,通过软模板法以1-十六烷基-3-甲基咪唑溴(C16mim+Br-)为结构导向剂,硫酸锆为无机前驱物合成了介观相氧化锆杂化物,然后该杂化物与固体硝酸铜无机盐研磨并进行热处理.在600℃焙烧后所得到的氧化锆材料具有蠕虫状介孔结构,且孔壁由尺寸约为2.50nm的四方相氧化锆纳米粒子组成.该材料的比表面积为240.0m2·g-1,孔径为4.10nm.与之对应,使用单一的软模板法在相同的温度焙烧后,所得到的氧化锆材料介孔结构坍塌,比表面积仅为9.5m·2g-1.     

无机合成与制备化学研究进展

本文从极端条件合成、软化学合成、特殊凝聚态和聚集态制备、形貌与尺寸修饰、缺陷与价态控制、组合化学合成、计算机辅助合成、理想合成与生物模拟合成等几个侧面, 阐述近年来无机合成与制备化学研究的进展。     

金属纳米颗粒镶嵌于沸石晶体：设计与制备高效多相催化材料的新策略

本文简要综述了近年来金属纳米颗粒镶嵌于沸石晶体的合成路线,包括在沸石介孔结构中引入金属纳米颗粒、金属组分的前驱体加入到沸石合成体系中以及采用晶种导向合成或无溶剂合成,所制备的催化材料与传统催化剂相比,具有优异的金属纳米颗粒抗烧结性、长反应寿命和高催化活性与选择性,这是设计与制备高效多相催化材料的新策略.     

贵金属多孔纳米结构的模板法制备及生物检测应用

贵金属多孔纳米材料是一类非常重要的新型多功能纳米材料,其具有独特的空心内部、多孔的外壁以及可调的形貌等,表现出优异的光、电、催化等特性。调制贵金属多孔纳米材料的尺寸、形状、排列和空间取向等对促进其在拉曼光谱、生物传感等方面的应用至关重要。模板法是利用与目标产物的纳米尺度特征相匹配的预制结构来指导纳米材料的合成,可以制备出其他方法难以制备的新型多孔纳米结构材料。基于模板的多样性,能够便捷的调节多孔贵金属的孔径、尺寸和组分,充分的开发贵金属纳米结构的特性。本文着重介绍了贵金属多孔纳米材料的类型和调控这些纳米结构的各种模板方法,分析了各种制备方法的优势和不足,并简要综述了贵金属多孔纳米结构在生物检测方面的一些应用进展。     

第二届全国无机固体化学和合成化学学术会议通知

中国化学会无机专业委员会拟定于1988年7月4日至了月9日在合肥中国科学技术大学召开第二届个国无机固体化学和合成化学会议。1.征文内容:缺陷化学、固相反应、固体表面和界面化学、固相中的扩散、无机固体新材料、复合金属氧化物、极端条件下的无机合成。固体化学中的制备方法、固态初质的分析和表征等。2.将论文详细摘要(1500字左右)一式二份寄北京大学化学系苏勉曾、或合肥中国科技大学材料系     

La（Oxin）3·3H2O纳米晶的一步固相化学合成及表征

在近室温条件和超声波作用下,通过固相化学反应一步合成了La（Oxin）3·3H2O（8-羟基喹啉镧）纳米晶。用X射线衍射及电子衍射法分析了固相产物的物相,用透射电子显微镜观测粒子的大小、形貌、粒径及粒径分布。结果表明,产物为颗粒大小均匀、平均粒径约为40nm的纳米晶,产率为95．9％。改变反应物、反应物配比、掺人惰性物质、加入微量溶剂或表面活性剂、研磨不同时间等固相反应条件对合成纳米晶的晶粒形貌、粒度和粒径分布有一定影响。合成的纳米晶材料具有操作方便、合成工艺简单、产率高、选择性好、粒径均匀、且粒度可控、污染少,同时又可以避免或减少液相中易出现的硬团聚现象等突出优点。     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

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.     

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%).     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.     

Synthesis of N-substituted carbazolones from α-iodo enaminones via Pd(0)-catalyzed intramolecular coupling under microwave irradiation

A variety of N-aryl and N-alkyl carbazolones were conveniently achieved in good to high yields via Pd₂(dba)₃-mediated intramolecular coupling of N-substituted α-iodo enaminones under microwave irradiation. The Pd(0)-catalyzed cyclization was found to proceed favorably with the more electron-deficient phenyl ring during the reactions involving unsymmetrical N,N-diaryl α-iodo enaminones. This unique property enables the construction of carbazolone skeleton containing nitro substituted benzenoid ring.     

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.     

Synthesis of substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles by intramolecular nitrilimine cycloaddition

Both substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles have been synthesized by the 3+2 intramolecular dipolar cycloaddition of nitrilimines to alkynes. This cyclization has been extended to more versatile 3-bromo derivatives by the use of alkynylbromides as dipolarophiles.     

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.