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Metal-organic Frameworks (metal-organic + frameworks)
Selected AbstractsEngineering Homochiral Metal-Organic Frameworks for Heterogeneous Asymmetric Catalysis and Enantioselective SeparationADVANCED MATERIALS, Issue 37 2010Yan Liu Abstract Owing to the potential applications in technological areas such as gas storage, catalysis, separation, sensing and nonlinear optics, tremendous efforts have been devoted to the development of porous metal-organic frameworks (MOFs) over the past ten years. Homochiral porous MOFs are particularly attractive candidates as heterogeneous asymmetric catalysts and enantioselective adsorbents and separators for production of optically active organic compounds due to the lack of homochiral inorganic porous materials such as zeolites. In this review, we summarize the recent research progress in homochiral MOF materials, including their synthetic strategy, distinctive structural features and latest advances in asymmetric heterogeneous catalysis and enantioselective separation. [source] Coordination Modulation Induced Synthesis of Nanoscale Eu1- xTbx -Metal-Organic Frameworks for Luminescent Thin FilmsADVANCED MATERIALS, Issue 37 2010Hailing Guo Strategies for synthesizing of nanoscale single or bimetallic lanthanide metal-organic framework (MOF) materials and their transformation into Eu1- xTbx -MOF thin films are reported. The thin films prepared via spin coating deposition method are smooth, dense and mechanically stable. They also exhibit marked luminescent properties and efficient Tb3+ -to-Eu3+ energy transferability. [source] Scintillating Metal-Organic Frameworks: A New Class of Radiation Detection Materials,ADVANCED MATERIALS, Issue 1 2009F. P. Doty Metal-organic frameworks containing an organic fluorophore such as stilbene dicarboxylate emit prompt visible light when they interact with ionizing radiation (e.g., high-energy protons or alpha particles). A completely new class of scintillation materials is created by this development, with the potential to rationally tailor properties for specific radiation detection applications. [source] Claisen,Schmidt Condensation Catalyzed by Metal-Organic FrameworksADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 4 2010Amarajothi Dhakshinamoorthy Abstract Metal-organic framework [Fe(BTC) (BTC=1,3,5-benzenetricarboxylic acid)] is a convenient heterogeneous catalyst for the carbon-carbon bond forming reaction in toluene between acetophenone and benzaldehyde to give selectively chalcone in high yield. Fe(BTC) appears as a general catalyst able to synthesize selectively different chalcone derivatives bearing various functionalities. Fe(BTC) could be recycled with no significant loss of catalytic efficiency and crystallinity in subsequent runs. [source] Metal-Organic Frameworks (MOFs) as Heterogeneous Catalysts for the Chemoselective Reduction of Carbon-Carbon Multiple Bonds with HydrazineADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 14-15 2009Amarajothi Dhakshinamoorthy Abstract The as-synthesized metal-organic frameworks (MOFs), particularly that based on aluminium coordinated with benzenedicarboxylic acid, constitute selective catalysts for the reduction of carbon-carbon multiple bonds in alkenes, alkynes and ,,,-unsaturated esters with hydrazine hydrate in acetonitrile under mild conditions. The present protocol enjoys advantages such as convenient reaction conditions and benign, reusable and cost effective catalyst. [source] Lanthanide Metal-Organic Frameworks as Ziegler,Natta Catalysts for the Selective Polymerization of IsopreneMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 22 2009Marta J. Vitorino Abstract The unprecedented ability of neodymium-based metal organic frameworks (MOFs) as polymerisation pre-catalysts towards isoprene is reported. Combined with methylaluminoxane (MAO) or modified MAO (MMAO), they afford mainly cis -selective polyisoprene, up to 90.7%. Both the activity and the selectivity are tentatively ascribed to the intrinsic microstructure of the starting materials. Compared to conventional carboxylates, MOFs associated to an Al co-catalyst are less active but the selectivity is found to be higher, and it may be modified by controlling the access to the pores, which would be favored at higher temperatures. Some residual crystalline MOF remains disseminated within the polymer matrix, as shown by X-ray diffraction and X-ray absorption spectroscopy studies. [source] New Metal-Organic Frameworks with Large Cavities: Selective Sorption and Desorption of Solvent MoleculesCHEMISTRY - A EUROPEAN JOURNAL, Issue 26 2007Yan Wang Abstract Five novel transition metal complexes [CdII3(tpba-2)2(SCN)6],6,THF,3,H2O (1), [CuII3(tpba-2)2(SCN)6],6,THF,3,H2O (2), [NiII3(tpba-2)2(SCN)6],6,THF,3,H2O (3), [CdII2(tpba-2)(SCN)3]ClO4 (4), [CuI3(SCN)6(H3tpba-2)] (5) [TPBA-2 = N,,N,,,N,,, -tris(pyrid-2-ylmethyl)-1,3,5-benzenetricarboxamide, THF=tetrahydrofuran] were obtained by reactions of the corresponding transition metal salts with TPBA-2 ligand in the presence of NH4SCN using layering or solvothermal method, respectively. The results of X-ray crystallographic analysis showed that complexes 1, 2 and 3 are isostructural and have the same 2D honeycomb network structure with Kagomé lattice, in which all the MII (M = Cd, Cu, Ni) atoms are six-coordinated, and the TPBA-2 ligands adopt cis,cis,cis conformation while the thiocyanate anions act as terminal ligands. Capsule-like motifs are found in 1, 2 and 3, in which six THF molecules are hosted, and the results of XPRD and solid-state 13C,NMR spectral measurements showed that the compound 1 can selectively desorb and adsorb THF molecules occurring along with the re-establishment of its crystallinity. In contrast to 1, 2 and 3, complex 4 has different 2D network structure, resulting from TPBA-2 ligands with cis,trans,trans conformation, thiocyanate anions serving as end-to-end bridging ligands, and the incomplete replacement of perchlorate anions, which further link the 2D layers into 3D framework by the hydrogen bonds. In complex 5, the CuII atoms are reduced to CuI during the process of solvothermal reaction, and the CuI atoms are connected by thiocyanate anions to form a 3D porous framework, in which the protonated TPBA-2 ligands are hosted in the cavities as templates. [source] Electrostatic-Field-Induced Enhancement of Gas Mixture Separation in Metal-Organic Frameworks: A Computational StudyCHEMPHYSCHEM, Issue 7 2006Qingyuan Yang Dr. Ordered microdomains with different electrostatic field strengths exist in certain metal-organic frameworks (MOFs; see picture), and the electrostatic interactions in MOFs can enhance the separation of some gas mixtures, demonstrating that MOFs have great potential for adsorption separations. [source] Scintillating Metal-Organic Frameworks: A New Class of Radiation Detection Materials,ADVANCED MATERIALS, Issue 1 2009F. P. Doty Metal-organic frameworks containing an organic fluorophore such as stilbene dicarboxylate emit prompt visible light when they interact with ionizing radiation (e.g., high-energy protons or alpha particles). A completely new class of scintillation materials is created by this development, with the potential to rationally tailor properties for specific radiation detection applications. [source] Engineering Homochiral Metal-Organic Frameworks for Heterogeneous Asymmetric Catalysis and Enantioselective SeparationADVANCED MATERIALS, Issue 37 2010Yan Liu Abstract Owing to the potential applications in technological areas such as gas storage, catalysis, separation, sensing and nonlinear optics, tremendous efforts have been devoted to the development of porous metal-organic frameworks (MOFs) over the past ten years. Homochiral porous MOFs are particularly attractive candidates as heterogeneous asymmetric catalysts and enantioselective adsorbents and separators for production of optically active organic compounds due to the lack of homochiral inorganic porous materials such as zeolites. In this review, we summarize the recent research progress in homochiral MOF materials, including their synthetic strategy, distinctive structural features and latest advances in asymmetric heterogeneous catalysis and enantioselective separation. [source] Versatile Supramolecular Copper(II) Complexes for Henry and Aza-Henry ReactionsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2009Guoqi Zhang Abstract Chiral supramolecular metal-organic frameworks assembled from copper complexes catalyse Henry and aza-Henry reactions of aromatic and aliphatic aldehydes and N -protected aromatic imines in high yield and good to excellent enantioselectivity. Reactions can be performed in the absence of base in ethanol or water. [source] Fabrication of free-standing ultrathin films of porous metal-organic frameworks by liquid-phase epitaxy and subsequent delaminationPHYSICA STATUS SOLIDI - RAPID RESEARCH LETTERS, Issue 8-9 2010Masih Darbandi Abstract In this work we describe an approach to fabricate MOF (metal-organic framework) platelets with predefined shapes and well-defined thicknesses. The process is based on growing thin, highly oriented and ordered MOF films by selective liquid-phase epitaxy on prestructured organic substrates. In a second step, the MOF platelets are delaminated employing a lift-off process. The freestanding MOF platelets were characterized with TEM and SEM, which showed no evidence of fracture or deformation of the delaminated shapes. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Topological relations between three-periodic nets.ACTA CRYSTALLOGRAPHICA SECTION A, Issue 3 2009The TOPOS program package was used to generate all subnets of 3- to 12-coordinated binodal nets taken from the Reticular Chemistry Structure Resource database. 38,304 binodal nets with novel topologies were revealed and stored in the TTD collection. A new invariant, the adjacency matrix of the shell graph of a node, is proposed to distinguish the node local topology. With this invariant, the first six examples of binodal- quasi -uninodal nets were discovered. 4604 organic and metal-organic frameworks were analyzed to find examples of the topologies generated. It was shown that many edge-transitive nets as well as unknown topologies occur in crystal structures. [source] Two-dimensional metal-organic frameworks containing linear dicarboxylatesACTA CRYSTALLOGRAPHICA SECTION B, Issue 5 2006Samuel M. Hawxwell The solvothermal synthesis of four two-dimensional metal-organic frameworks containing linear dicarboxylic acids as ligands for ZnII centres is described. Zn(BDC)(DMF) [(1) where BDC = benzene-1,4-dicarboxylic acid; DMF = N,N -dimethylformamide] adopts a common paddlewheel motif leading to a 44 grid network, whereas Zn3(BDC)3(EtOH)2 (2), Zn3(BDC)3(H2O)2·4DMF (3) and Zn3(BPDC)3(DMF)2·4DMF (4) each form networks with the relatively uncommon 36 topology based upon Zn3(O2CR)6 secondary building units. All contain coordinated solvent molecules, namely DMF [(1) and (4)], ethanol (2) or H2O (3). Comparison of structures (2) and (3) illustrates a clay-like flexibility in interplanar spacing which sheds light on the ability of the Zn3(BDC)3 framework to undergo desolvation and uptake of small solvent and gas molecules. [source] Hochdurchsatzmethoden zur Entdeckung und Optimierung kristalliner poröser MaterialienCHEMIE-INGENIEUR-TECHNIK (CIT), Issue 7 2010N. Stock Prof. Abstract Hochdurchsatz (HD)-Methoden erlauben eine systematische und effiziente Untersuchung komplexer Parameterräume, wie sie oft bei Solvothermalsynthesen beobachtet werden. Ihr Einsatz ermöglicht es, schneller neue Verbindungen zu entdecken, Synthesebedingungen zu optimieren bzw. Reaktionstrends ausfindig zu machen. Mit einem unterschiedlichen Ausmaß an Parallelisierung, Miniaturisierung und Automatisierung der einzelnen Arbeitsschritte wurden innerhalb des letzten Jahrzehnts einige HD-Methodiken entwickelt, deren Einsatz zu neuen herausragenden mikroporösen Verbindungen im Bereich der Zeolithe, ZIFs (zeolithic imidazolate frameworks) und MOFs (metal-organic frameworks) geführt haben. [source] Electrostatic-Field-Induced Enhancement of Gas Mixture Separation in Metal-Organic Frameworks: A Computational StudyCHEMPHYSCHEM, Issue 7 2006Qingyuan Yang Dr. Ordered microdomains with different electrostatic field strengths exist in certain metal-organic frameworks (MOFs; see picture), and the electrostatic interactions in MOFs can enhance the separation of some gas mixtures, demonstrating that MOFs have great potential for adsorption separations. [source] Hydrothermal Synthesis, Crystal Structures and Photoluminescence of Two Novel Metal-organic Supramolecular Frameworks Based on Mixed Ligands of Dipyrazino[2,3- f:2,,3,-h]quinoxaline and Pyridine-2,5-dicarboxylic AcidCHINESE JOURNAL OF CHEMISTRY, Issue 9 2008Xiu-Li WANG Abstract Two novel metal-organic frameworks [Zn2(Dpq)2(2,5-pda)2(H2O)2]·2H2O (1) (dipyrazino[2,3- f:2,3,- h]quinoxaline=Dpq) and [Cd2(Dpq)2(2,5-pda)2]·2H2O (2) (pyridine-2,5-dicarboxylic acid=2,5-H2pda) have been obtained from hydrothermal reactions of two different metal(II) nitrates with the same mixed ligands Dpq and 2,5-H2pda, and structurally characterized by elemental analyses, TG, IR spectroscopy, and single-crystal X-ray diffraction analyse. Single-crystal X-ray analyses show that the metal ions are bridged by different coordination modes of 2,5-pda to form a dimer in 1, 2D rhombic grid in 2, respectively. In the compound 1, adjacent dimers are packed through hydrogen bonds and - aromatic stacking interactions to form a distorted , -Po supramolecular structure. In the compound 2, adjacent polymer layers are further linked by hydrogen bonds to form a distorted , -Po 3D supramolecular framework stabilized by - stacking interactions. The different structures of compounds 1 and 2 illustrate the influence of the metal ions and ligands on the self-assembly of polymeric coordination architectures. In addition, the title compounds exhibit blue emission in the solid state at room temperature. [source] | |||||||||||||||||||||||||