Architectures supramoléculaires à structures ouvertes fondées sur la liaison hydrogène : élaboration, caractérisation structurale et propriétés de sorption

La thématique de recherche développée au cours de cette thèse de doctorat concerne la conception de réseaux supramoléculaires poreux à propriétés de sorption remarquables. Ces travaux visent l'élaboration des solides supramoléculaires poreux dont la cohésion est assurée par des liaisons-Hydrogène (liaisons-H), la caractérisation structurale, ainsi que l'étude des propriétés de sorption pour les matériaux les plus prometteurs. Les solides supramoléculaires poreux sont obtenus en associant par le biais des liaisons-H, des composés de coordination préformés (accepteurs de liaisons-H) et des cations organiques (donneurs de liaisons-H par le biais de groupements N-H+) dans les conditions de la chimie douce. Dans le cadre de cette thèse, nous nous sommes intéressés à l'association de complexes de coordination de type métal-oxalates ([Al(Ox)3]3-, [Zr(Ox)4]4-où Ox = C2O42-) et des cations organiques comme les dérives d'imidazolium et de pyridinium de topicité et de charge variables. Plusieurs architectures cristallines supramoléculaires ont été obtenues. L'influence des paramètres expérimentaux au moment de leur formation a été étudiée. L'importance de la concentration de la solution, de la stœchiométrie des réactifs, des solvants utilisés et de la température a ainsi été mise en évidence. Nous nous sommes aussi attachés à faire varier des facteurs intrinsèques aux unités de construction comme le nombre et la nature de sites donneur/accepteur de liaison-H ainsi que la présence (ou non) de sites encombrants et/ou susceptible de donner de liaisons-H supplémentaires sur les cations. Ainsi, des architectures supramoléculaires poreuses possédant des volumes vides allant de 10 % jusqu'à 54 % ont été obtenues. Le matériau de porosité la plus importante présente une structure 3D chirale parcourue par des canaux de diamètre de 11 Å. Ce matériau a la capacité de piéger au sein de ces cavités une large gamme de molécules hôtes. La possibilité de faire de la chimie dans les cavités a été également mise en évidence.The project developed in this PhD thesis focuses on the design of porous supramolecular frameworks showing interesting sorption properties. The aims of this work were: i) to synthesize porous supramolecular materials by hydrogen bonds (H-bonds) assembling, ii) to investigate their crystal structures and iii) to study, when they are porous, their sorption properties. The materials have been prepared under mild conditions associating preformed anionic metallotectons (the H-bonds acceptors) through cationic organic molecules (the H-bonds donors by means of N-H+ groups) via charge assisted H-bonds. In this work, different types of association involving anionic metal-oxalate building blocks ([Al(Ox)3]3-, [Zr(Ox)4]4- with Ox = C2O42-) and organic cations (imidazolium and pyridinium derivatives) have been achieved. Thus, several supramolecular architectures have been obtained. The influence of experimental parameters on supramolecular arrangements has been explored. The effect such as solution concentration, reactant stoichiometry, solvent nature and mixture temperature has been determined. Then, intrinsic modifications (i.e. number and nature of the donor/acceptor H-bonds sites as well as additional bulky groups) have been applied on building blocks and their impact has been further evaluated. This has successfully afforded several porous molecular materials showing 10 % to 54 % of accessible void volume. The material showing the highest porosity presents a 3D chiral architecture endowed by large channels (11 Å of diameter). Interestingly, this compound is able to host a wide range of guest molecules (acidic molecules, halogenated molecules, metal ions ...). Moreover, it shows promising results regarding chemical reaction inside its cavities

Architectures supramoléculaires à structures ouvertes fondées sur la liaison hydrogène (élaboration, caractérisation structurale et propriétés de sorption)

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

Titanium coordination compounds: from discrete metal complexes to metal–organic frameworks

International audienc

Tubular crystals growth for a nanoporous hydrogen-bonded metal–organic framework

A supramolecular architecture formed by H-bonded assemblage of ditopic bisimidazoliumbenzene cations with anionic metal-oxalate modules shows permanent porosity upon guests release; the reversible sorption process being accompanied by crystal-to-crystal transformations. Additional macroporosity for the material was achieved by controlled growth of crystals with tubular morphology

Natural abundance oxygen-17 solid-state NMR of metal organic frameworks enhanced by dynamic nuclear polarization

International audienceThe 17 O resonances of Zirconium-oxo clusters that can be found in porous Zr carboxylate metal-organic frameworks (MOFs) have been investigated by magic-angle spinning (MAS) NMR spectroscopy enhanced by dynamic nuclear polarization (DNP). High-resolution 17 O spectra at 0.037 % natural abundance could be obtained in 48 hours, thanks to DNP enhancement of the 1 H polarization by factors = S with /S without = 28, followed by 1 H 17 O cross-polarization, allowing a saving in experimental time by a factor of ca. 800. The distinct 17 O sites from the oxo-clusters can be resolved at 18.8 T. Their assignment is supported by density functional theory (DFT) calculations of chemical shifts and quadrupolar parameters. Protonation of 17 O sites seems to be leading to large characteristic shifts. Markedly, natural abundance 17 O NMR spectra of diamagnetic MOFs can thus be used to probe and characterize the local environment of different 17 O sites on an atomic scale

Metal–Organic Frameworks and Water: ‘From Old Enemies to Friends’?

Since their discovery a few decades ago, metal–organic frameworks (MOFs) have suffered from poor hydrolytic stability. Since then, significant effort has been devoted to design robust MOFs, including their utilization for water-related applications to overcome relevant societal challenges. This short review provides guidelines on the key parameters that drive the assembly of hydrothermally stable MOFs together with the most relevant physicochemical features needed in their water-related applications. It also highlights some of the recent advances in MOF-water applications (based on water sorption or mediation and separation in the presence of water) as well as the most critical challenges to overcome

Cadre métallique organique et son utilisation pour la génération de H2

The present invention relates to metal-organic frameworks (MOFs) which contain trimetallic centres with pyrazole as a ligand in the structure thereof. Particularly, it relates to MOFs which contain units of formula (I). The present invention also relates to a photocatalytic method for generating H2 starting from liquid water or vapour using said materials.NoConsejo Superior de Investigaciones Científicas, Universitat Politècnica de València, Paris Sciences et Lettres, École Superieure de Physique et de Chimie Industrielles de la Ville de Paris, Centre National de la Recherche Scientifique, École Normale SuperieureA1 Solicitud de patente con informe sobre el estado de la técnic

Natural Abundance Oxygen-17 Solid-State NMR of Metal Organic Frameworks Enhanced by Dynamic Nuclear Polarization

The 17O resonances of Zirconium-oxo clusters that can be found in porous Zr carboxylate metal-organic frameworks (MOFs) have been investigated by magic-angle spinning (MAS) NMR spectroscopy enhanced by dynamic nuclear polarization (DNP). High-resolution 17O spectra at 0.037 % natural abundance could be obtained in 48 hours, thanks to DNP enhancement of the 1H polarization by factors e(1H) = Swith/Swithout = 28, followed by 1H®17O cross-polarization, allowing a saving in experimental time by a factor of ca. 800. The distinct 17O sites from the oxo-clusters can be resolved at 18.8 T. Their assignment is supported by density functional theory (DFT) calculations of chemical shifts and quadrupolar parameters

Supramolecular open-framework architectures based on dicarboxylate H-bond acceptors and polytopic cations with three/four N-H+ donor units

International audienceSupramolecular assemblages based on anionic H-acceptors and cationic H-donors have been envisioned to elaborate open frameworks maintained by ionic H-bonds. Combinations of di-anionic chloranilate (CA2-), oxalate (Ox2-), or terephthalate (BDC2-) and trisimidazolium or tetrapyridinium derivatives (three and four N-H+ donors, respectively) yielded five architectures of formulae [(H3TrIB)(CA)1.5[middle dot]2DMF[middle dot]2.5H2O] (1), [(H4Tetrapy)(CA)2[middle dot]3DMF] (2), [(H3TrIB)(HOx)(Ox)[middle dot]5H2O] (3), [(H4Tetrapy)(Ox)2[middle dot]5H2O] (4), and [(H4Tetrapy)(BDC)2(H2O)[middle dot]1DMF[middle dot]3H2O] (5) (with TrIB = 1,3,5-trisimidazolylbenzene and Tetrapy = tetrakis[(pyridine-4-yloxy)methyl]methane). Four of these, i.e.1, 2, 4 and 5, show an open framework. Their assembling patterns and framework dimensionalities are mainly governed by the chemical features of the cation. 1D (3) and 2D (1) networks are found with [H3TrIB]3+, whereas 3D diamond-type networks (2, 4, 5) are systematically formed with [H4Tetrapy]4+. While the individual adamantanoid cages exhibit large voids in all 3D structures, net catenations (with a total degree of interpenetration up to 19) reduce the potential porosities of the solids to 17-32%. The largest solvent accessible void (42%) is found for the 2D supramolecular organization of 1, for which net interpenetration does not take place. Crystal structures for all five architectures are reported. Framework robustness upon guest departure and gas sorption properties have been explored for materials 1 and 2 with the highest potential accessible voids