An unusual 3D polycatenane motif generated by the 2D -> 2D parallel -> 3D parallel interpenetration of (4,4) sheets

A fascinating 3D polycatenane-like metal-organic framework with two kinds of helical chains was reported, in which the helical chains exhibit multiple interweaving modes based on the unusual 2D -> 2D parallel -> 3D parallel interpenetration.

Facile shape-controlled synthesis of luminescent europium benzene-1,3,5-tricarboxylate architectures at room temperature

The large-scale synthesis of the metal-organic framework Eu(1,3,5-BTC)center dot 6H(2)O nanocrystallites with delicate morphologies such as sheaflike, butterflylike, and flowerlike superstructures composed of nanowires have been realized via a simple solution phase method at room temperature. Time-dependent experiments indicate that these superstructures were constructed by the splitting crystal growth mechanism, as has been noted in some minerals in nature. The synthetic parameters such as reaction time, concentration and molar ratio of reactants, surfactant, and reaction temperature all affected the morphology of the Eu(1,3,5-BTC)center dot 6H(2)O architectures. These well-arranged architectures exhibit red emission corresponding to the D-5(0) -> F-7(2) transition of the Eu3+ ions under UV light excitation, and the lifetime is determined to be about 0.22 ms.

Coordination-Induced Formation of One-Dimensional Nanostructures of Europium Benzene-1,3,5-tricarboxylate and Its Solid-State Thermal Transformation

Novel one-dimensional europium benzene-1,3,5-tricarboxylate compressed nanorods have been synthesized oil it large scale through direct precipitation in solution phase under moderate conditions without the assistance of any surfactant, catalyst, or template. The obtained nanorods have widths of about 50-100 not, thicknesses of 10-20 nm, and lengths ranging from a few hundred nanometers to several micrometers. X-ray powder diffraction. elemental analysis, Fourier transform infrared Studies, and thermogravimetric and differential thermal analysis show that the nanorods have the structural formula of Eu(1,3,5-BTC)center dot 6H(2)O. Upon UV excitation, these nanorods exhibit a highly efficient luminescence. which comes from the Eu3+ ions. Moreover, Eu2O3 nanorods Could also be obtained via a thermal decomposition method using the corresponding complex as a precursor. This synthetic route is promising for the preparation of other one-dimensional crystalline nanomaterials because of its simplicity and the low cost of the starting reagents.

Self-assembly of a water chain with tetrameric and decameric clusters in the channel of a mixed-valence (CuCuII)-Cu-I complex

The reaction of Cu(BF4)(2) with pyridine-2,6-dicarboxylic acid (H(2)pydc) and trans-1,2-bis(4-pyridyl)ethylene (bpe) under hydrothermal conditions afforded a porous mixed-valence (CuCuII)-Cu-I coordination polymer. Coexistence of tetrameric and decameric water clusters within the channels of the complex leads to a novel water chain. The metal-organic framework provides both hydrophilic and hydrophobic environments for stabilizing the clusters and retains its integrity upon dehydration and rehydration.

Syntheses and crystal structures of [Mn(H2O)(4)(bpy)]L center dot 4H(2)O, [Mn(H2O)(4)(bpy)]L ' center dot 4H(2)O (H2L = SUCCINIC ACID, H2L ' = FUMARIC ACID)

Reactions of freshly prepared M(OH)(2-2x)(CO3)(x) (.) yH(2)O (M = Mn, Zn) and 4,4'-bipyridine (bpy) with succinic acid (H2L) or famaric acid (H2L') in CH3OH-H2O afforded [Mn(H2O)(4)(bpy)]L (.) 4H(2)O, 1, [Mn(H2O)(4)(bpy)]L' (.) 4H(2)O, 2 and [Zn(H2O)(4)(bpy)]L (.) 4H(2)O, 3. The three coordination polymers are isostructural and consist of (1)(infinity)[M(H2O)(4)(bpy)(2/2)](2+) cationic chains, crystal H2O molecules and dicarboxylate anions (succinate or fumarate anions). Within the chains, the metal atoms are each octahedrally coordinated by four aqua oxygen atoms and two pyridyl nitrogen atoms from two 4,4'-bipyridine ligands. The crystal H2O molecules are hydrogen bonded to dicarboxylate anions to form ribbon-like anionic chains. The cationic and anionic chains are interconnected via hyqrogen bonds to generate a 3D network. Crystal data: 1 triclinic, P (1) over bar, a = 7.235(1), b = 7.749(2), c = 10.020(2) Angstrom, alpha = 79.95(3), beta = 88.79(3), gamma = 71.39(3)degrees, V = 523.9(2) Angstrom(3) and D-cal = 1.494 g cm(-3) for Z = 1; 2 triclinic, P (1) over bar, a = 7.127(1), b = 7.800(2), c = 9.945(2) Angstrom, alpha = 80.26(3), beta = 87.86(3), gamma = 72.69(3)degrees, V = 520.2(2) Angstrom(3) and D-cal = 1.498 g cm(-3) for Z = 1; 3 triclinic, P (1) over bar, a = 7.189(1), b = 7.764(2), c = 9.843(2) Angstrom, alpha = 79.16(3), beta = 87.80(3), gamma = 71.29(3)degrees, V = 510.9(2) Angstrom(3) and D-cal = 1.559 g cm(-3) for Z = 1.

Phenylthiolate as a sigma- and pi-donor ligand: synthesis of a 3-D organometallic coordination polymer [K2Fe(SPh)(4)](n)

The synthesis and crystal structure of the first mixed-metal organometallic polymer network containing phenylthiolato ligands, [K2Fe(SPh)(4)](n), are investigated. The simple phenyl-thiolate acts as a sigma- and pi-donor ligand to give a 3-D potassium iron coordination polymer with both metal-carbon and metal-sulfur coordination interactions.

Two new Cu-II coordination polymers: Studies of topological networks and water clusters

Two new Cull coordination polymers, namely [Cu-2(BDC)(2)(L)(4)(H2O)(2)]center dot 14H(2)O (1) and [Cu-1.5(BTC)(L)(1.5)(H2O)(0.5)]center dot 2H(2)O (2), where L = 1,1'-(1,4-butanediyl)bis(imidazole), BDC = 1,4-benzene dicarboxylate, and BTC = 1,3,5-benzenetricarboxylate, have been synthesized at room temperature. Complex 1 exhibits an unusual, square-planar, four-connected 2D (2)(6)4 net, which has been predicated by Wells. Interestingly, three types of water clusters, namely (H2O)(6), (H2O)(8), and (H2O)(10), are observed in the hydrogen-bonded layers constructed by the BDC ligands and water molecules. The BTC anion in compound 2 is coordinated to the Cu" cation as tetradentate ligand to form a (6(6))(2)(4(2)6(4)8(4))(2)(6(4)810) net containing three kinds of nonequivalent points, Thermogravimetric analyses (TGA) and IR spectra for 1 and 2 are also discussed in detail.

Post-synthetic modification of metal–organic frameworks

Post-synthetic modification (PSM) of metal-organic frameworks encompassing the chemical transformation of the linker present is a promising new route for engineering optical centres and tuning the light emission properties of materials, both in the visible and in the near infrared (NIR) spectral regions. Here, PSM of isoreticular metal-organic framework-3 (IRMOF-3) with ethyl oxalyl monochloride, ethyl acetoacetate, pentane-2,4-dione, 3-(2- hydroxyphenyl)-3-oxopropanal, 2-chloroacetic acid, glyoxylic acid, methyl vinyl ketone and diethyl (ethoxymethylene)malonate followed by chelation of trivalent lanthanide ions afforded intriguing near infrared (Nd3+) and visible (Eu3+, Tb3+) light emitters. IRMOF-3 was used as a case in point due to both its highly porous crystalline structure and the presence of non-coordinating amino groups on the benzenedicarboxylate (bdc) linker amenable to modification. The materials were characterised by elemental analysis, powder X-ray diffraction, optical, scanning and transmission electron microscopy, Fourier transform infrared spectroscopy, and liquid and solid-state nuclear magnetic resonance. The solid-state luminescence properties of Ln-modified-IRMOF-3 were investigated at room temperature. The presence of the bdc aromatic ring, β– diketonate and oxalate enhanced the Ln3+ sensitization via ligand-to-metal energy transfer (anthena effect). As far as photocalysis is concerned, we have synthesized metal−organic frameworks (Cr-MIL-125-AC, Ag-MIL-125-AC) by a green method (solid–vapors reactions). The resulting functionalized materials show a photocatalytic activity for methylene blue degradation up to 6.52 times larger than that of the commercial photocatalyst hombikat UV-100. These findings open the door for further research for improving the photocatalytic performance of metal-organic frameworks.

Molecular simulation of gas adsorption equilibria in nanoporous materials

This work is divided into two distinct parts. The first part consists of the study of the metal organic framework UiO-66Zr, where the aim was to determine the force field that best describes the adsorption equilibrium properties of two different gases, methane and carbon dioxide. The other part of the work focuses on the study of the single wall carbon nanotube topology for ethane adsorption; the aim was to simplify as much as possible the solid-fluid force field model to increase the computational efficiency of the Monte Carlo simulations. The choice of both adsorbents relies on their potential use in adsorption processes, such as the capture and storage of carbon dioxide, natural gas storage, separation of components of biogas, and olefin/paraffin separations. The adsorption studies on the two porous materials were performed by molecular simulation using the grand canonical Monte Carlo (μ,V,T) method, over the temperature range of 298-343 K and pressure range 0.06-70 bar. The calibration curves of pressure and density as a function of chemical potential and temperature for the three adsorbates under study, were obtained Monte Carlo simulation in the canonical ensemble (N,V,T); polynomial fit and interpolation of the obtained data allowed to determine the pressure and gas density at any chemical potential. The adsorption equilibria of methane and carbon dioxide in UiO-66Zr were simulated and compared with the experimental data obtained by Jasmina H. Cavka et al. The results show that the best force field for both gases is a chargeless united-atom force field based on the TraPPE model. Using this validated force field it was possible to estimate the isosteric heats of adsorption and the Henry constants. In the Grand-Canonical Monte Carlo simulations of carbon nanotubes, we conclude that the fastest type of run is obtained with a force field that approximates the nanotube as a smooth cylinder; this approximation gives execution times that are 1.6 times faster than the typical atomistic runs.

Síntese hidrotermal assistida por micro-ondas como metodologia sintética eficiente para obtenção da rede metalorgânica [ZN(BDC)(H2O)2]n

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A 2D coordination polymer with brick-wall network topology based on the [Cu(NCS)(2)(pn)] monomer

The new complex [Cu(NCS)(2)(pn)] (1) (pn = 1,3-propanediamine) has been synthesized and characterized by elemental analysis, infrared and electronic spectroscopy. Single crystal X-ray diffraction studies revealed that complex 1 is made up of neutral [Cu(NCS)(2)(pn)] units which are connected by mu-1,3,3-thiocyanato groups to yield a 2D metal-organic framework with a brick-wall network topology. Intermolecular hydrogen bonds of the type NH...SCN and NH...NCS are also responsible for the stabilization of the crystal structure. (c) 2007 Elsevier B.V. All rights reserved.

Síntese e caracterização da MOF NH2-MIL-125(Ti) e sua aplicação como catalisador na reação de condensação de Knoevenagel

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Ni/Pd@MIL-101: Synergistic Catalysis with Cavity-Conform Ni/Pd Nanoparticles

Deutsche Forschungsgemeinschaft [SFB 840]

A reverse crystal Engineering approach

The enormous impact of crystal engineering in modern solid state chemistry takes advantage from the connection between a typical basic science field and the word engineering. Regrettably, the engineering aspect of organic or metal organic crystalline materials are limited, so far, to descriptive structural features, sometime entangled with topological aspects, but only rarely with true material design. This should include not only the fabrication and structural description at micro- and nano-scopic level of the solids, but also a proper reverse engineering, a fundamental discipline for engineers. Translated into scientific language, the reverse crystal engineering refers to a dedicated and accurate analysis of how the building blocks contribute to generate a given material property. This would enable a more appropriate design of new crystalline material. We propose here the application of reverse crystal engineering to optical properties of organic and metal organic framework structures, applying the distributed atomic polarizability approach that we have extensively investigated in the past few years[1,2].

Sustainable Catalysis : Rational Pd Loading on MIL-101Cr-NH2 for More Efficient and Recyclable Suzuki-Miyaura Reactions

Palladium nanoparticles have been immobilized into an amino-functionalized metal-organic framework (MOF), MIL-101Cr-NH2, to form Pd@MIL-101Cr-NH2. Four materials with different loadings of palladium have been prepared (denoted as 4-, 8-, 12-, and 16wt%Pd@MIL-101Cr-NH2). The effects of catalyst loading and the size and distribution of the Pd nanoparticles on the catalytic performance have been studied. The catalysts were characterized by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared (FTIR) spectroscopy, powder X-ray diffraction (PXRD), N-2-sorption isotherms, elemental analysis, and thermogravimetric analysis (TGA). To better characterize the palladium nanoparticles and their distribution in MIL-101Cr-NH2, electron tomography was employed to reconstruct the 3D volume of 8wt%Pd@MIL-101Cr-NH2 particles. The pair distribution functions (PDFs) of the samples were extracted from total scattering experiments using high-energy X-rays (60keV). The catalytic activity of the four MOF materials with different loadings of palladium nanoparticles was studied in the Suzuki-Miyaura cross-coupling reaction. The best catalytic performance was obtained with the MOF that contained 8wt% palladium nanoparticles. The metallic palladium nanoparticles were homogeneously distributed, with an average size of 2.6nm. Excellent yields were obtained for a wide scope of substrates under remarkably mild conditions (water, aerobic conditions, room temperature, catalyst loading as low as 0.15mol%). The material can be recycled at least 10times without alteration of its catalytic properties.