Search results for "Metal-organic"
showing 10 items of 224 documents
Investigation of Charge-Transfer Interactions Induced by Encapsulating Fullerene in a Mesoporous Tetrathiafulvalene-Based Metal-Organic Framework
2019
<p>The design of Metal-Organic Frameworks (MOFs) incorporating electroactive guest molecules in the pores has become a subject of great interest in order to install additional electrical functionalities within the framework while maintaining porosity. In this direction, understanding the charge-transfer (CT) process between the framework and the guest molecules is crucial towards the design of new electroactive MOFs. Herein, we present the encapsulation of fullerenes (C<sub>60</sub>) in a mesoporous tetrathiafulvalene(TTF)-based MOF. The CT process between the electron-acceptor C<sub>60 </sub>guest and the electron-donor TTF ligand is studied in detail by means…
Metal-organic frameworks-based catalysts for biomass valorization
2020
Abstract The objective of this chapter is to review the most promising metal-organic framework (MOF) catalysts in biomass valorization processes in the bulk and fine chemical industries. Either bulk metal-organic frameworks, encapsulated catalytic species in MOFs, or MOF-derived catalysts are revised in terms of activity, selectivity, and stability for biomass valorization applications. The work revised here is focused on the transformation of lignocellulose biomass through purely chemical pathways. In the first part of the chapter, the few studies of cellulose hydrolysis into monosaccharides reported are commented, since this crucial first step in the valorization of hemicellulose is expec…
Temperature-Induced Structural Transitions in the Gallium-Based MIL-53 Metal–Organic Framework
2013
We report a structural and thermodynamic investigation of the phase behavior of Ga(OH,F)-MIL-53, a gallium-based metal–organic framework (MOF) having the MIL-53 topology containing 0.7 wt % fluorine bonded to the metal. Despite some small structural differences, especially for the hydrated form, the overall physical chemistry behavior of Ga(OH,F)-MIL-53 is very similar to standard fluorine free Ga-MIL-53 material. A combination of in situ X-ray diffraction, in situ Fourier transform infrared spectroscopy, differential scanning calorimetry, and heat capacity measurements allowed us to establish that Ga(OH,F)-MIL-53 under vacuum (i.e., the empty material) exhibits two stable phases: a nonporo…
Selective Gold Recovery and Catalysis in a Highly Flexible Methionine-Decorated Metal–Organic Framework
2016
A novel chiral 3D bioMOF exhibiting functional channels with thio-alkyl chains derived from the natural amino acid l-methionine (1) has been rationally prepared. The well-known strong affinity of gold for sulfur derivatives, together with the extremely high flexibility of the thioether "arms" decorating the channels, account for a selective capture of gold(III) and gold(I) salts in the presence of other metal cations typically found in electronic wastes. The X-ray single-crystal structures of the different gold adsorbates Au(III)@1 and Au(I)@1 suggest that the selective metal capture occurs in a metal ion recognition process somehow mimicking what happens in biological systems and protein r…
Bidirectional Chemo-Switching of Spin State in a Microporous Framework
2009
The ins and outs of spin: Using the microporous coordination polymer {Fe(pz)[Pt(CN)(4)]} (1, pz=pyrazine), incorporating spin-crossover subunits, two-directional magnetic chemo-switching is achieved at room temperature. In situ magnetic measurements following guest vapor injection show that most guest molecules transform 1 from the low-spin (LS) state to the high-spin (HS) state, whereas CS(2) uniquely causes the reverse HS-to-LS transition.
Copper( ii ) complexes with phosphorylated 1,10-phenanthrolines: from molecules to infinite supramolecular arrays
2016
International audience; The reaction of phosphorylated 1,10-phenanthrolines 3-Pphen, 3,8-Pphen and 4,7-Pphen (3-Pphen = 3-diethoxyphosphorylphenanthroline, 3,8-Pphen = 3,8-bis(diethoxyphosphoryl) phenanthroline, 4,7-Pphen = 4,7-bis(diethoxyphosphoryl) phenanthroline) and hydrated copper(II) nitrate in a 1 : 1 ratio leads to the formation of supramolecular architectures. In the 1D coordination polymer [Cu(3-Pphen)(NO3)(2)](n) (2) the copper atom is coordinated to only one phenanthroline ligand and the coordination sphere is completed by two oxygen atoms of nitrate anions and the oxygen atom of the phosphoryl group from the neighbouring phenanthroline ligand. Complex Cu(3,8-Pphen)(NO3)(2) (3)…
Crystal structure of a low-spin poly[di-μ3-cyanido-di-μ2-cyanido-bis(μ2-2-ethylpyrazine)dicopper(I)iron(II)]
2019
In the title metal–organic framework, [Fe(C6H8N2)2{Cu(CN)2}2] n , the low-spin FeII ion lies at an inversion centre and displays an elongated octahedral [FeN6] coordination environment. The axial positions are occupied by two symmetry-related bridging 2-ethylpyrazine ligands, while the equatorial positions are occupied by four N atoms of two pairs of symmetry-related cyanide groups. The CuI centre is coordinated by three cyanide carbon atoms and one N atom of a bridging 2-ethylpyrazine molecule, which form a tetrahedral coordination environment. Two neighbouring Cu atoms have a short Cu...Cu contact [2.4662 (7) Å] and their coordination tetrahedra are connected through a common edge between…
Crystal structure of catena-poly[[[(2-ethoxypyrazine-κN)copper(I)]-di-μ2-cyanido] [copper(I)-μ2-cyanido]]
2019
The title compound, {[Cu(EtOpz)(CN)2][CuCN]}n, where EtOpz is 2-ethoxypyrazine, is a two-dimensional polymeric copper complex with different coordination environments of the two CuI ions. One Cu atom is coordinated to the 2-ethoxypyrazine molecule and two bridging cyanide ligands, equally disordered over two sites. The second Cu atom is coordinated by two disordered over two sites bridging cyanide groups. Two copper–cyanide chains are connected through Cu⋯Cu contact.
Incorporation of zeolitic imidazolate framework (ZIF-8)-derived nanoporous carbons in methacrylate polymeric monoliths for capillary electrochromatog…
2017
A series of metal organic frameworks-derived nanoporous carbons originating from zeolitic imidazolate framework-8 (ZIF-8) crystals as precursors have been prepared via varying the preparation conditions. The ZIF-8-derived carbons were subsequently admixed in the methacrylate monomers containing polymerization mixtures and polymerized to obtain monolithic columns for capillary electrochromatography (CEC). The effect of particle size and content of the ZIF-8-derived carbon materials in the polymerization mixture on the performance of the hybrid monolithic columns was investigated in detail. The resulting composites were characterized using scanning electron microscopy. Using short time UV-ini…
Nanoparticle-Directed Metal–Organic Framework/Porous Organic Polymer Monolithic Supports for Flow-Based Applications
2017
A two-step nanoparticle-directed route for the preparation of macroporous polymer monoliths for which the pore surface is covered with a metal–organic framework (MOF) coating has been developed to facilitate the use of MOFs in flow-based applications. The flow-through monolithic matrix was prepared in a column format from a polymerization mixture containing ZnO-nanoparticles. These nanoparticles embedded in the precursor monolith were converted to MOF coatings via the dissolution–precipitation equilibrium after filling the pores of the monolith with a solution of the organic linker. Pore surface coverage with the microporous zeolitic imidazolate framework ZIF-8 resulted in an increase in su…