金属有机骨架材料制备双金属或多金属催化材料及其应用

金属有机骨架（metal-organic framework,简称MOF）材料的研究在近几年相当热门,因其各种优异的性质,在催化领域得到广泛应用。然而,其本身作为催化剂的研究并不多且应用较为局限。但MOF材料规则的多孔结构及较大的比表面积为负载高分散金属纳米催化剂提供了天然的物理空间,能有效阻止金属纳米颗粒的团聚及浸出;使催化剂与反应物充分接触,有利于催化反应的进行,这也是近年来MOF材料作为催化剂的一个主要研究方向。本文着重讨论通过不同的方法将金属纳米颗粒负载在MOF材料上制备双金属或多金属催化剂并在催化领域的应用。重点介绍一锅合成法、化学吸附还原负载法、金属有机化学气相沉积法、固相研磨法等制备方法,较为详细地介绍了其在氧化（醇、烷烃、烯烃和CO氧化）、加氢（羰基类化合物和烯烃类化合物加氢）、Knoevenagel缩合、光催化（光催化降解有机物和光解水产氢）等反应中的应用,讨论了这类新型功能催化剂材料所存在的问题并对其进一步发展前景做出展望。     

金属有机框架材料在催化领域的研究现状与展望（英文）

金属有机骨架材料(MOF)又称多孔配位聚合物(PCP),是一类由金属团簇和有机配体通过配位作用形成的新型晶态多孔材料.近30年, MOF材料在催化领域受到了广泛的关注和研究.MOF的多孔结构和高比表面积可以实现催化位点的空间分离并促进物质传输,从而提高催化活性.MOF可以像均相催化剂一样在原子精度进行灵活剪裁和调控,同时具有非均相催化剂易分离回收的优势.通过结合均相和非均相催化剂的优点, MOF表现出了诸多优于传统催化材料的独特性质.本文首先简要介绍了MOF基催化材料设计的基本原理和MOF应用于催化的独特性,其次对MOF在催化中面临的瓶颈和局限进行了论述,最后指出了MOF在未来催化领域中潜在的独特应用前景.MOF材料中金属节点、有机配体和孔空间都可以进行灵活功能化,从而赋予催化活性.金属节点上的不饱和配位点可作为路易斯酸催化中心.配体可以通过修饰不同功能基团从而赋予催化活性.此外,金属节点和有机配体还可以通过接枝外来催化位点进行功能化.更重要的是, MOF孔空间可以限域客体活性单元,极大扩展了活性位的来源.MOF还可以作为前驱体通过化学转化获得多孔碳、金属化合物及其复合材料.MOF的高...     

金属-有机骨架材料在烯烃氧化中的应用

本文分别从以骨架中的金属(金属簇)为催化中心的MOF材料、利用具有催化活性的刚性有机配合物构筑的MOF材料和MOF负载催化材料三个方面详细介绍了MOF作为催化剂在烯烃氧化反应中的应用情况,分析了其各自的优缺点。具有催化活性的刚性有机配合物构筑的MOF材料稳定性较好,能够引入具有光学活性的催化剂,可以作为不对称催化氧化催化剂使用,是未来的一个研究发展方向。     

金属-有机骨架材料及其在催化反应中的应用

金属-有机骨架(metal-organic frameworks, MOFs)材料是由金属离子和有机配体通过自组装而成的具有多孔结构的特殊晶体材料。由于其种类的多样性、孔道的可调性和结构的易功能化,已在气体的吸附和分离、催化、磁学、生物医学等领域表现出了诱人的应用前景。本文介绍了MOFs材料的类型和常用的合成方法,综述了近年来MOFs材料在催化领域的应用,特别是以MOFs材料中骨架金属作为活性中心、骨架有机配体作为活性中心和负载催化活性组分的催化反应,并对MOFs材料的催化应用趋势做了展望,以期对MOFs材料的催化性能有比较全面的认识。     

纳米球型Mo-MOF材料的调控合成及催化硫醚选择性氧化

金属有机骨架材料是一种由无机金属离子和有机配体配位组成的复合材料,拥有较高的金属分散度和催化活性.本文采用静态混合溶剂热晶化法,以钼酸为钼源、对苯二甲酸为配体合成了有机骨架材料Mo-MOF.通过X射线衍射（XRD）、傅里叶变换红外光谱（FTIR）、扫描电子显微镜（SEM）和X射线光电子能谱（XPS）等手段表征了催化剂的形貌、结构和组成.采用静态混合溶剂热法（水和乙醇）合成的Mo-MOF催化剂表现出最佳的催化活性,在未加其它助剂的条件下实现二苯基硫醚与氧气的选择性氧化,并可以得到100%的转化率和86.4%的二苯基亚砜的选择性.     

金属有机框架材料对Cr(Ⅵ)离子的吸附去除研究进展

重金属离子污染问题一直备受关注。开发利用多孔材料吸附去除水中重金属离子一直是材料、环境等相关学科领域的研究热点之一。金属有机框架材料（metal-organic frameworks,MOFs）是一类新型的多孔材料,具有结构多样、比表面积大、孔径可调、孔表面特征易设计调控等特点,在气体分离、催化、传感等领域表现出极大的应用潜力。近年来,高稳定MOF材料的构筑取得了许多重大突破,大量研究工作探索了这类材料在水中的应用,包括水中重金属离子的吸附去除。Cr （Ⅵ）离子是一类毒性大、分布广的重金属离子,不同条件下存在形态多样,其吸附去除研究具有理论和实际意义。本文主要综述了近年来利用MOF材料吸附去除水中Cr （Ⅵ）离子的研究工作,并将这些材料归属为：（1）高稳定的锆基MOF、（2）阳离子框架型MOF、（3）后修饰的MOF及（4） MOF基复合材料4类;也对这些材料的Cr （Ⅵ）离子吸附机理、吸附量、材料再生性等进行了概括;最后分析了MOF材料在重金属离子吸附去除实际应用上存在的问题并展望了今后的重点研究方向。     

金属有机骨架材料在二氧化碳加氢中的应用

大气中二氧化碳(CO_2)浓度的急剧增加引起了人们的关注,并提出了许多将CO_2转化为高价值化学品的策略。金属有机框架材料(MOFs)由于其独特的孔隙率、大的比表面积、丰富的孔结构、多活性中心、良好的稳定性和可回收性,可用于二氧化碳的捕获和催化转化。基于晶体多孔材料的金属有机骨架(MOF)设计和合成的各种功能纳米材料可以作为多相催化剂或载体/前体来应对这些挑战。在本文中,笔者将主要关注MOFs在催化二氧化碳加氢领域的最新研究进展,包括催化加氢制备一氧化碳、甲烷、甲酸、甲醇和烯烃,分析了基于MOFs的催化剂的合成方法和提高催化活性的原因。介绍了提高新型MOF材料的催化活性和探索新的CO_2转化可行的策略。讨论了MOF型催化剂在CO_2化学转化中的主要挑战和机遇,对本研究领域中进一步的发展进行了简要的展望。     

金属有机框架复合材料的合成及其在肿瘤诊疗领域中的应用

金属-有机框架(MOF)材料是指以有机配体为连接体和以金属离子簇为节点,通过配位键组装形成的具有周期性结构的配位化合物。该材料在气相传导、光学催化以及生物应用领域都有着应用潜力。不同形貌、大小和组分的MOF材料具有不同的物理化学性质。将金属纳米粒子和MOF材料的性能相结合,就能够有效地避免金属纳米粒子和MOF材料的相互凝聚。本文主要阐述了MOF材料的几种合成方法,包括气相法、液相法、固相法、模板法、微波法和电化学法,并对其优缺点进行了讨论。重点分析了其在肿瘤领域中的应用,包括药物负载、荧光标记和光动力学疗法等。最后指出今后其主要的研究方向是改善生物相容性、降低制备成本、扩展生物MOF及其负载药物的种类,使其应用到更多疾病的治疗上。     

垂直自支撑式金属有机框架多级结构单晶用于锂定向沉积

金属有机框架材料(MOF)是由金属离子或簇和有机配体通过配位键自组装形成的多孔晶体材料.MOF及其衍生物具有开放金属位点和极大的比表面积,广泛地应用在催化领域.然而,MOF材料由于存在暴露活性位点较少,传质受限或易发生不可控制的聚集等问题,会导致活性位点的损失,极大地限制了其在催化领域的应用.多级结构不仅提供更多的暴露...     

MOF(Fe)的制备及其氧气还原催化性能

以硝酸铁为金属离子前驱体、均苯三甲酸为有机配体,采用水热法合成了金属有机骨架MOF（Fe）催化剂,应用X射线衍射、N₂吸附-脱附、透射电镜、红外光谱和热重等方法对催化剂的结构进行了表征,并采用循环伏安法测试了催化剂在碱性电解质中的氧气还原（ORR）催化性能,同时也采用旋转圆盘电极进一步研究了催化剂的ORR的动力学行为.?结果表明,所制MOF（Fe）具有很好的晶型结构、大比表面积、丰富的微孔以及较高的热稳定性. 且表现出很好的ORR催化活性. ORR的反应历程随电位的改变而改变：电位在-0.3到0.50 V范围内,ORR为2电子途径;随着电位从-0.50 V升至-0.95 V,ORR从2电子向4电子途径转变. 另外,该催化剂在碱性电解质中也表现出较好的氧气析出（OER）催化性能,这为制备用于ORR和OER的高效非贵金属催化剂提供了新的途径.     

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.     

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.