Puckered-boat conformation (H2O)14 cluster on the self-assembly of an inorganic-metal-architecture

BDC (phthalic acid) reacts with EuCl₃ to form 1D coordination polymer, in the presence of phen (1,10-phenanthroline) under hydrothermal conditions. Puckered-boat-shaped (H₂O)₁₄ water clusters resulted from four free water molecules and six coordinated water molecules, which join these chains to make a sheet. Of further interesting, the water clusters associate into an inorganic (carbon-free) sheet with chlorine anions by hydrogen bonds. This hybrid water–chlorine configuration acts as a “host” supporting the metal-organic “guest”.     

基于三维框架材料H3PW6Mo6O40/Zn(BDC)(4,4'-Bipy)0.5高效吸附亚甲基蓝

采用溶剂热法,用H3PW6Mo6O40对金属有机骨架Zn(BDC)(4,4'-Bipy)05进行改性,制备出金属有机骨架复合材料H3PW6Mo6O40/Zn(BDC)(4,4'-Bipy)0.5.利用IR、XRD、TG、SEM对其结构进行分析.同时,以亚甲基蓝溶液模拟染料废水进行吸附实验,考察了初始pH、温度对吸附容量的影响,探究了其吸附等温线和动力学特征.实验结果表明,H3PW6Mo6O40/Zn(BDC)(4,4'-Bipy)05对亚甲基蓝有很好的吸附性能,在20℃和pH 2的条件下,吸附量达588.24mg/g,且该吸附符合Langmuir等温吸附模型和拟二级动力学方程,吸附过程自发且放热.     

Living mono- and biradical polymerizations in homogeneous system synthesis of AB and ABA type block copolymers

Summary To design the structure of the block copolymers by radical polymerization, benzyl N,N-diethyldithiocarbamate (BDC) and p-xylylene N,N-diethyldithiocarbamate(XDC) were used as mono- and bifunctional photo-iniferters, respectively, for the polymerizations of styrene(St) and methyl methacrylate (MMA). These polymerizations proceeded via a living radical mechanism. When the ratio of the concentration of the diethyldithiocarbamate group to that of a photo-iniferter molecule was kept constant, the yields of the polymers obtained by both BDC and XDC were identical, and their molecular weights (¯M) by XDC were two times as high as those by BDC. This observation strongly suggested that the polymerizations by BDC and XDC were performed by living mono- and biradical mechanisms, respectively. By using the polymers obtained by BDC and XDC as polymeric photo-iniferters of the polymerization of second monomers, the AB and ABA type block copolymers were obtained, respectively.     

柔性MOFs材料Cu(BDC)的氨气吸附及可逆转化性能

氨气（NH₃）作为氮肥合成的主要原料和PM_2.5的重要间接来源,在工业生产倡导绿色循环的大势之下,减排与回收是绿色发展的必行之路。基于吸附法具有氨气无相变,富集得到的氨气可以直接与二氧化碳反应合成氮肥（如尿素）的优势,研究了具有可逆转化性质的柔性MOFs材料Cu（BDC）的氨气吸附性能。实验中通过水热法制备了三维致密结构的Cu（BDC）（DMF）,高温加热脱除DMF后晶体结构发生改变,得到了具有一维孔道结构的Cu（BDC）材料,比表面积为535 m²·g^-1,纯氨气的吸附量在一个大气压下高达18.4 mmol·g^-1,高于传统吸附剂以及其他新型的多孔MOFs和COFs等材料,并且通过减压和加热,材料可以逐步实现再生,具有优良的“载氨”特性。直接制备的Cu（BDC）（DMF）也可以在氨气的环境中（DMF被NH₃替代）转变为Cu（BDC）（NH₃）₂,省去了制备Cu（BDC）的过程。     

芳香羧酸（苯基多羧酸）配合物研究进展

介绍了苯二甲酸、苯三甲酸、苯四甲酸等为配体的芳香羧酸配合物的配位模式,如苯二甲酸根据取代位置的不同,有对苯二甲酸,间苯二甲酸,邻苯二甲酸,与一元羧酸相比,配体中两个羧基的存在使得这些配体的配位模式更趋多样化,从而更有利于构筑高维结构的配位聚合物。综述了近几年芳香羧酸配合物的研究进展,表明芳香羧酸在组装超分子结构和合成配位聚合物方面有着突出的优势,特别是在金属有机配合物中占有重要地位。     

Hydrothermal Syntheses and Crystal Structures of Two Coordination Polymers with Terephthalic Acid and N-Donor Ligand: 2-Methyldipyrido[3,2-f:2′,3′-h]quinoxaline

Two 3D coordination polymers, [Cd(BDC)(Medpq)·H₂O]_n 1, and [Co(BDC)(Medpq)·H₂O] _n 2 (BDC = terephthalic acid, Medpq = 2-Methyldipyrido[3,2-f:2′,3′-h]quinoxaline), have been synthesized by self-assembly. The structure analyses show that both of the two coordination polymers are formed by 1D infinite chains through non-covalent interactions, and both of them are based on 1D zigzag ones. The photoluminescent study of the coordination polymer [Cd(BDC)(Medpq)·H₂O] _n shows that it exhibit fluorescent emission bands at 567.7 nm.     

Effects of reaction conditions on poly(methyl methacrylate) polymerized by living radical polymerization with iniferter

Living radical polymerization of methyl methacrylate (MMA) through the use of benzyl diethyl dithiocarbamate (BDC) was studied. The aim was to investigate the role of the concentration, BDC‐to‐MMA mol ratio, and reaction time upon the molecular weight, polydispersity, and conversion of the product. It was found that the molecular weight and the conversion increase with increase of the concentration at the expense of low polydispersity. The reaction time also played a significant role, especially at a relatively long reaction time where molecular weight, polydispersity, and conversion increased with increasing reaction time. In terms of the mol ratio effect, it was found that there was a critical mol ratio for maximum conversion. The results indicate that the kinetics of polymerization of MMA through the use of a BDC inifeter is different from that in the presence of a conventional initiator. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 938–944, 2000     

Synthesis of polyisoprene-poly(methyl methacrylate) block copolymers by using polyisoprene as a macro-iniferter

Summary Polyisoprene (PI) was pre-polymerized by using benzyl diethyldithiocarbamate (BDC) as an iniferter. The obtained PI was subsequently used to react with methyl methacrylate (MMA) in order to investigate whether the relevant block copolymers can be achieved. Results from ¹H-NMR and GPC reveal that the PI-PMMA block copolymers were formed. This suggests that polymerization of isoprene through the use of BDC proceeded via a (psuedo) “living” mechanism. Received: 9 August 1999/Revised version: 27 September 1999/Accepted: 1 October 1999     

Ligand-bridged oligomeric and supramolecular arrays of the hexanuclear rhenium selenide clusters--exploratory synthesis, structural characterization, and property investigation

Transition metal clusters, by virtue of their well-defined structures and unique properties, present themselves as an attractive class of structural and functional building blocks for molecular and supramolecular construction. Summarized in this Account are highlights of our efforts utilizing face-capped octahedral [Re(6)(mu(3)-Se)(8)](2+) clusters as the fundamental building units to create a wide variety of preprogrammed architectures. These include molecular "Tinkertoys", featuring stereospecific cluster units bridged by multitopic ligands and extended arrays of clusters engineered via hydrogen bonding and secondary metal-ligand coordination.     

H6P2M09W9O62/Zn(BDC)(Bipy)0.5复合材料催化合成3,4-二氢嘧啶-2(H)酮衍生物

采用水热法分别合成杂多酸H6P2Mo9W9O62及有机金属骨架Zn(BDC) (Bipy)0.5,使用浸渍法合成H6P2Mo9W9O62/Zn(BDC) (Bipy)05复合材料,用该复合材料催化醛、乙酰乙酸乙酯和尿素通过Biginelli反应,乙醇作溶剂,合成6种3,4-二氢嘧啶-2(H)酮衍生物.通过IR、1HNMR、13CNMR确定其结构,通过m.p.确定其纯度.实验结果表明:固定醛用量为0.04 mol,n(醛)∶n(乙酰乙酸乙酯)∶n(尿素)=1∶1.4∶1.5,2.0 wt％ H6P2Mo9W9O62/Zn(BDC)(Bipy)0.5,反应温度为105℃,反应时间为60 min时,产物收率为40.1％～91.5％.     

H_6P_2Mo_(15)W_3O_(62)修饰三维金属有机骨架Cu(BDC)(4,4'-Bipy)_(0.5)吸附亚甲基蓝

采用溶剂热法,在合成金属有机骨架Cu(BDC)(4,4'-Bipy)_(0.5)的过程中引入活性组分H_6P_2Mo_(15)W_3O_(62),制备出一种新型吸附剂H_6P_2Mo_(15)W_3O_(62)/Cu(BDC)(4,4'-Bipy)_(0.5)。利用IR、XRD、BET、SEM对其结构进行分析,进而研究其亚甲基蓝的吸附性能。研究结果表明,H_6P_2Mo_(15)W_3O_(62)/Cu(BDC)(4,4'-Bipy)_(0.5)对亚甲基蓝有很好的吸附性能,在40℃和pH 2的条件下吸附量达78.8 mg/g。H_6P_2Mo_(15)W_3O_(62)/Cu(BDC)(4,4'-Bipy)_(0.5)对亚甲基蓝的吸附符合Langmuir等温吸附型和拟二级动力学模型,吸附过程是一个自发和吸热过程。     

BDC工艺对废水脱氮除磷的研究与应用

研究BDC工艺除氮脱磷,讨论pH值、曝气、悬浮物等因素的影响,并对BDC工艺中脱氮除磷的相互影响进行了探讨,给出了同时脱氮除磷的BDC运行方法,使磷铵厂氮磷废水达到中水回用的目的。     

Bridging homogeneous and heterogeneous catalysis with MOFs: Cu-MOFs as solid catalysts for three-component coupling and cyclization reactions for the synthesis of propargylamines,indoles and imidazopyridines

Copper-containing MOFs are found to be active, stable and reusable solid catalysts for three-component couplings of amines, aldehydes and alkynes to form the corresponding propargylamines. Two tandem reactions, including an additional cyclization step, leads to the effective production of indoles and imidazopyridines. In particular, the lamellar compound [Cu(BDC)] (BDC = benzene dicarboxylate) is highly efficient for the preparation of imidazopyridines, although a progressive structural change of the solid to a catalytically inactive compact structure is produced, causing deactivation of the catalyst. Nevertheless, the phase change can be reverted by refluxing in DMF, which recovers the original lamellar structure and the catalytic activity of the fresh material. The use of [Cu(BDC)] for this reaction also prevents the formation of Glaser/Hay condensation products of the alkyne, even when the reaction is performed in air atmosphere. This is a further advantage of [Cu(BDC)] with respect to other homogeneous copper catalysts, for which the use of an inert atmosphere is necessary.     

Fabrication of nanosheets of a fluorescent metal–organic framework [Zn(BDC)(H2O)]n (BDC = 1,4-benzenedicarboxylate): Ultrasonic synthesis and sensing of ethylamine

A supramolecular metal–organic framework (MOF) constructed by two-dimensional (2D) infinite coordination polymers, [Zn(BDC)(H₂O)]_n (1, BDC = 1,4-benzenedicarboxylate), was synthesized by the reaction of zinc acetate with H₂BDC in dimethylformamide (DMF) under ultrasonic irradiation at ambient temperature and atmospheric pressure. Yield of 1 varied from 43.4% to 53.2% for the reaction time of 10–90 min. Samples with different morphologies, i.e. nanobelts, nanosheets, and microcrystals, were obtained under ultrasound irradiation for different reaction times. Fluorescence emission of nanosheets of [Zn(BDC)(H₂O)]_n was found to be highly sensitive to ethylamine, and solid state fluorescence intensity decreased with increasing contents of ethylamine in acetonitrile solution due to weak fluorescence quenching effect.     

Hydrothermal Syntheses,Crystal Structure and Luminescent Properties of Two New Zn(II) Coordination Polymers

Two new zinc(II) coordination polymers; namely, [Zn(BDC)(L)_0.5]_n (1) and {[Zn(BDC)(L)]·3H₂O}(2), were successfully synthesized by the assembly of Zn(II) ion, 1.2-benzene-dicarboxylate acid (H₂BDC) and 1,4-bis(2-methylimidazole-3-ium-1-yl) biphenyl (L). A change in the pH values resulted in complexes with different compositions and dimensionalities. Formed at the lower pH, 1 exhibits a three-dimensional structure with mab topology. At a higher pH, 2 shows a two-dimensional structure, which contains one-dimensional helical chains. The luminescent properties for 1 and 2 were investigated in the solid state at room temperature.     

Preparation,thermal characterization and tribological evaluation of some polyquinazolinediones and polyquinazolones

The preparation of a series of pre-polymers by solution polycondensation of 4,4′-diaminodiphenyl-3,3′-dicarboxylic acid (BDC) and di-isocyanates, and the melt polycondensation of BDC and diacetyl derivatives of aromatic diamines is described. These pre-polymers have been characterized and cyclized to yield polyquinazolinediones and polyquinazolones whose structures and thermal stabilities have been investigated. The physical characteristics of films made from these materials were determined after cyclization, and friction and wear characteristics of composite films containing polytetrafluoroethylene, lead oxide and graphite were evaluated in a journal bearing bush configuration. The relationship between wear behaviour and polymer structure, thermal stability and physical properties is discussed.     

MIL-53/4A沸石复合材料的制备及吸附水性能的研究

通过水热合成法制备4A沸石分子筛,在4A沸石分子筛上制备了金属有机骨架(MIL-53)/4A沸石复合材料,研究了原材料配比、晶化时间和晶化温度对复合材料结构的影响,得到了制备复合材料结构的最佳实验条件:4A与对苯二甲酸摩尔比例为0.8:1,晶化时间为10 h,晶化温度为443 K.利用X射线衍射(XRD)、扫描电子显微镜(SEM)、傅里叶红外光谱(FTIR)、氮气吸附对该复合材料进行表征,并对该材料吸附水蒸气性能进行了测试.结果表明该复合材料具有微孔的孔道结构,并具有较好的亲水性.     

Self-assembly of 2,6-naphthalenedicarboxylic acid and 4,4′-biphenyldicarboxylic acid on highly oriented pyrolytic graphite and Au(1 1 1) surfaces

Self-assemblies of 2,6-naphthalenedicarboxylic acid (NDC) and 4,4′-biphenyldicarboxylic acid (BDC) molecules on the highly oriented pyrolytic graphite (HOPG) and reconstructed Au(1 1 1) surfaces has been, respectively, studied by using scanning tunneling microscopy (STM). The NDC molecules form an incommensurate structure, while BDC molecules form a commensurate structure on the HOPG surface. The aromatic rings take the same orientation with that of the underlying HOPG substrate to gain optimum adsorbate-substrate interactions. On the Au(1 1 1) surface, both molecules form incommensurate structures. The orientations of aromatic ring locate about 20° with respect to the gold rows, the 〈1 1 0〉 direction. On the HOPG surface, the whole carboxyl groups are invisible, while the carbon atoms of the carboxyl groups may appear bright on the gold surface.     

Controlling the Molecular Assembly of Polyoxometalates from the Nano to the Micron Scale: Molecules to Materials

Polyoxometalates (POMs) represent a class of metal-oxide units based upon oxides of Mo, W, V, and Nb. Such cluster building blocks can also be subsequently self-organized in complex 1D, 2D, and 3D frameworks leading to functional materials with diverse properties that span size ranges from 1 to 7 nm in terms of the size of the largest molecular units/clusters. However, since the cluster building blocks have great structural flexibility, the design of architectures is non-trivial due to the sensitive dependence on reaction parameters such as pH, cation type, temperature, templating and linking units, ionic strength, redox agents. Therefore, the ability to control the aggregation or linking of the building blocks to give pre-defined structure-types as well as engineering the physical properties — for example, optical, electronic, catalytic activity/reactivity — is a tremendous challenge. In this review we survey our work from the control/design point of view and show how it is becoming possible to control the assembly of POM-based architectures. We also describe the polyoxometalate-based molecules-to-material transformations that can be seen as an osmotically driven crystal morphogenesis producing tubular architectures. This can be described as a new type of emergent phenomenon.     

Porous Cd-carboxylate frameworks tuned by the bulk of linker: Interpenetrated nets,selective CO2 uptakes and high water vapor adsorption

Reported herein are two porous interpenetrated anionic Cd-carboxylate frameworks tuned by the length of organic linker. Shorter BDC linker and [Cd(COO)₄] building blocks in 1 generate a rare 4-connected 2-fold interpenetrating qtz network. But longer NDC linker in 2 produces a self-penetrated 8-connected bcu framework with [Cd₃(COO)₈] SBUs. 1 and 2 both show selective CO₂ adsorption and significantly, 2 exhibits the highest water vapor uptake performance (281 cm³·g^− 1 at 298 K and P/P₀ = 0.95) among all the interpenetrated MOFs.