氮化硼纳米片及其凝胶材料的研究进展

氮化硼纳米片具有高机械强度、良好的化学惰性和热稳定性等优点.除了这些性质,基于纳米氮化硼的凝胶材料还有高比表面积、大孔隙率等特点.因此它在催化、储氢、除污和气体吸附等领域具有潜在的应用前景.这篇综述主要介绍了氮化硼纳米片及其凝胶材料的制备,举例说明了氮化硼凝胶的关键应用并加以展望.     

二维材料的一维纳米带

自石墨烯被发现以来,二维材料研究成为一个新的研究热点。当二维材料制备成一维纳米带结构后,由于宽度方向上的限域效应和边缘结构的差异,导致其具有区别于二维材料的独特的电学、光学和磁学性质,因此逐步成为科学家关注的焦点。本文主要介绍了石墨烯、石墨炔、联苯烯、氮化硼、黑磷、过渡金属二硫族化合物等二维材料的一维纳米带的结构、制备方法和性能研究。首先讨论了二维材料制备成一维纳米带后的结构与性能的改变;其次,着重阐述了典型的纳米带制备方法,包括“自上而下”和“自下而上”两种策略,如二维片层刻蚀、打开纳米管、化学合成、化学气相沉积、外延生长及碳纳米管限域生长等方法,实现可控制备指定纳米宽度与具有特定边缘结构的纳米带,最终获得不同于其二维材料本体的特殊性能。最后,总结了不同方法制备纳米带的优缺点,提出了需要克服的困难和挑战,并展望了未来的研究方向,希望能引起国内外同行的广泛关注。     

氮化硼负载的高分散Au-CuOx纳米颗粒用于低温CO氧化

负载型金催化剂显示出高的低温CO氧化活性,其催化性能与载体的性质密切相关.近年来,六方氮化硼作为一种新型催化材料引起了极大关注.已有研究表明,二维结构的氮化硼纳米片有利于传质扩散,并且暴露出大量的表面和边缘,作为新型非金属催化剂在烷烃氧化脱氢中表现出优异的活性.同时,CO氧化反应是强放热过程,氮化硼具有优良的导热性能,...     

新型多孔氮化硼材料

多孔氮化硼材料是一种新型多孔非氧化物材料,具有高比表面积、可调孔径、良好的化学惰性和热稳定性等特点,在催化、储氢、气体吸附和分离等领域具有巨大的应用潜力,是材料领域研究热点之一。依孔径的不同,多孔氮化硼材料被分为微孔氮化硼、介孔氮化硼、大孔氮化硼和多级孔氮化硼。本文综述了微孔、介孔、大孔及多级孔等类型氮化硼材料的研究进展。重点介绍了不同类型氮化硼材料的制备和性能,并分析了各种制备方法的优缺点,最后探讨了多孔氮化硼材料的发展前景。     

氮化硼纳米片在重防腐涂层中的应用进展

氮化硼纳米片也被称为"白色石墨烯",是一种重要的纳米填料,具有优异的机械性、导热性、耐磨性、阻隔性、疏水性,同时也是一种新兴的性能优良的绝缘材料.被广泛应用于重防腐涂层、润滑剂、传感器等领域.基于氮化硼纳米片在金属腐蚀防护领域巨大的应用前景,本综述将从氮化硼纳米片的制备及表面官能化、氮化硼薄膜防护涂层、氮化硼纳米片/有机防护涂层、氮化硼纳米片-无机复合材料/有机防护涂层这四部分进行系统总结,重点围绕氮化硼纳米片在有机涂层中均匀分散能力以及金属腐蚀防护能力等方面等进行详细分析和介绍,同时对氮化硼纳米片基防腐涂料未来发展进行了展望.     

三维(3D)石墨烯及其复合材料的应用

三维（3D）石墨烯通常是指具有3D结构的二维（2D）石墨烯组装体,是近年来石墨烯化学领域的新型功能性材料。将2D石墨烯片整合成具有3D结构的组装体可以有效调控石墨烯的电学、光学、机械、化学和催化特性,因此3D石墨烯材料不仅具有石墨烯固有的理化性质,其三维多孔的微/纳米结构还使其兼具比表面积大、机械强度高、电子传导能力优越及传质快速等优良特性。这些独特的性质使3D石墨烯及其复合材料在材料科学领域备受关注。研究发现,3D石墨烯及其复合材料应用于纳米电子学、能量储存和转换、化学和生物传感等研究领域均表现出优越的性能。本文结合当前研究热点,综述了3D石墨烯及其复合材料在催化、储氢/气体吸附、传感器、环境修复、超级电容器等领域中的应用进展,并简要评述目前3D石墨烯材料应用中所面临的挑战及发展前景。     

二维炭基多孔材料的合成及应用（英文）

二维材料是指厚度在纳米尺度,且在两个维度(长和宽)具有较大尺寸的材料。与块体材料相比,二维材料最大的特点是具有极高的表面/体积比,有利于传质、传热和离子扩散,因而在吸附、催化以及储能等领域有广泛的应用。近年来,随着石墨烯引发的二维材料研究浪潮,二维炭基多孔材料成为全世界关注的研究热点。而二维炭基材料的孔结构是影响其性能的关键因素。本文介绍了近年来二维炭基多孔材料的合成方法,包括炭纳米片及炭-无机复合纳米片的制备,讨论了制备条件对材料孔结构的影响。在此基础上,着重介绍了二维炭基材料在吸附、多相催化及储能方面的应用。最后,对新型炭基二维材料开发中仍存在的关键科学问题进行了总结和展望。     

溶剂热法制备Bi2S3纳米材料

0引言纳米材料具有特殊的结构和性能,可广泛应用于化学、物理学、电子学、光学、机械和生物医药学等领域[1￣5]。其中一维或准一维纳米结构体系或纳米材料的研究既是研究其它低维材料的基础,又与纳米电子器件及微型传感器密切相关,是近年来国内外研究的前沿[6￣9]。近年来,人们虽然做了许多尝试来制备一维纳米结构材料,但合成这类材料特别是合成半导体一维纳米材料仍然是一个巨大的挑战。随着维数的减小,半导体材料的电子能态发生变化,其光、电、声、磁等方面性能与常规体材料相比有着显著的不同[10￣12]。Bi2S3是一种重要的半导体材料,受…     

静电纺丝纳米纤维基超级电容器电极材料的研究进展

静电纺丝纳米纤维具有比表面积大、孔隙率高及密度低等优势,是电化学储能材料的理想候选者之一.本文综述了近年来静电纺丝碳纳米纤维、金属氧化物/硫化物/氮化物、导电聚合物及其复合材料在超级电容器领域的研究及应用进展,探讨了材料组成、结构与电化学电容性能之间的关系,并对静电纺丝纳米纤维基电极材料的发展前景进行了展望.这将为新型高性能超级电容器电极材料的结构设计与可控制备提供新思路.     

模板法合成纳米结构材料

模板法（包括硬模板和软模板法）是制备纳米结构材料的常用方法,可用来制备多种物质的各种形状（如：球形粒子、一维纳米棒、纳米线、纳米管以及二维有序阵列等）的纳米结构,近年来关于这一领域的研究较为活跃。本文介绍了近年来利用氧化铝、二氧化硅、碳纳米管、表面活性剂、聚合物、生物分子等作模板制备多种物质的纳米结构材料的一些进展。     

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.     

Copper catalyzed/mediated synthetic methodology for ebselen and related isoselenazolones

Scope of the copper catalyzed/mediated selenium-nitrogen coupling reaction has been studied for the synthesis of isoselenazolones. It is noticed that the 2-chloro, 2-bromo-, and 2-iodo-aryl amides substrates can be exploited in the selenium-nitrogen coupling reaction by employing 25-100 mol % of CuI/1,10-phenanthroline (L) and potassium carbonate as a base in DMF. Furthermore, electron rich 2-chloro-arylamides also underwent selenium-nitrogen coupling reaction to give biologically important selenium-nitrogen heterocycles. Also, copper-catalyzed selenium-nitrogen coupling reaction has been meticulously applied for the synthesis of diaryl diselenides having methoxy, amine, and amide functionality from respective aryl iodides in the presence of stoichiometric amount of succinimide as an external Se-N coupling partner.