Дисертації з теми "Multi-functional Metal Organic Frameworks"
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Cadman, Laura. "Multi-component metal-organic frameworks." Thesis, University of Bath, 2017. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.723319.
Повний текст джерелаАнотація:
The synthesis of metal-organic frameworks (MOFs) with new structures and multi-functional pore environments is an area of growing research interest. One route to forming materials of this kind is through the synthesis of multi-component MOFs, which may include multiple organic ligand types or metals in the framework. This thesis presents new examples of multi-component MOFs which aim to demonstrate how this approach affects the properties of the resulting frameworks. Chapter 1 details the terminology surrounding metal-organic frameworks and includes a review of the literature. The overall aims of the thesis are presented at the end of this chapter. A series of mixed-ligand MOFs are presented in Chapter 2, combining multiple organic ligands which perform the same structural role within the framework but contain different functionalities. X-ray diffraction studies revealed that the pore size and geometry of the products can be systematically altered through compositional control. Chapter 3 is an investigation into defect formation through the systematic inclusion of a dicarboxylate ligand into frameworks based on tricarboxylate ligands. X-ray diffraction and gas adsorption studies on the mixed-ligand products show them to be isostructural to the single ligand analogues and contain defects which induce porosity into an otherwise non-porous system. The preparation of zinc-based anionic MOFs which contain viologen cations in their pores are detailed in Chapter 4. A reduction of the viologen counter-ions from the dication (yellow) to the radical cation (blue) was observed with heating or irradiation. Stability of the viologen radical cations within the MOFs was investigated through electron paramagnetic spectroscopy and was shown to be dependent on the framework topology. Finally, Chapter 5 describes the synthesis and characterisation of a range of mixed-lanthanide coreshell MOFs, containing gadolinium, terbium and europium. These materials exhibit different emission properties than those of an isostructural framework containing randomly distributed lanthanide centres.
2
Kearns, Eleanor Rose. "Multi-stimuli Metal-organic frameworks and their composites." Thesis, The University of Sydney, 2022. https://hdl.handle.net/2123/29561.
Повний текст джерелаАнотація:
Metal-Organic Frameworks (MOFs) are a versatile class of materials. Their high surface area combined with the functionality of their constituent organic ligands make them suitable for a wide range of applications. In their scale-up to industry level uses, MOFs face several roadblocks. The largest of these obstacles are large-scale green syntheses of MOFs and processing the polycrystalline powders into useable forms. This thesis examines structure-activity relationships in a family of TTF-based MOFs, and presents a green synthesis for UiO-66-NH2. Finally, 3D-printing will be examined as a method for preparing MOF-based electrocatalytic electrodes.
Chapter 3 and Chapter 4 will examine the structure-activity relationships (SARs) of charge transfer and photocyclization respectively. Herein, a family of photoactive TTF-based MOFs, generated by systematically varying the framework constituents, are used to probe the effect of structure on the intervalence charge-transfer (IVCT) and [2+2] photocyclisation processes.
Chapter 5 presents a novel one-step mechanochemical synthesis of UiO-66-NH2. This synthesis proceeds from ZrOCl2.8H2O in a 66% yield. The mechanochemical synthesis presented is more scalable than other benign syntheses of UiO-66-NH2, and importantly yields highly crystalline material with comparable surface area to UiO-66-NH2 synthesized via alternative mechanochemical routes.
Chapter 6 presents the first example of 3D-printed MOF electrodes for electrocatalysis, which expands upon previous work on 3-D printed MOF and zeolite-based composite sorbent materials. This represents a new technique for electrochemical analysis of solid analytes, as well as the development of self-supporting solid MOF-based electrodes. This research shows that the properties of the MOF are maintained once printed, and a clear electrochemical response to the analyte of interest is observed.
3
Carson, Fabian. "Development of Metal–Organic Frameworks for Catalysis : Designing Functional and Porous Crystals." Doctoral thesis, Stockholms universitet, Institutionen för material- och miljökemi (MMK), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-115819.
Повний текст джерелаАнотація:
Metal–organic frameworks, or MOFs, have emerged as a new class of porous materials made by linking metal and organic units. The easy preparation, structural and functional tunability, ultrahigh porosity, and enormous surface areas of MOFs have led to them becoming one of the fastest growing fields in chemistry. MOFs have potential applications in numerous areas such as clean energy, adsorption and separation processes, biomedicine, and sensing. One of the most promising areas of research with MOFs is heterogeneous catalysis. This thesis describes the design and synthesis of new, carboxylate-based MOFs for use as catalysts. These materials have been characterized using diffraction, spectroscopy, adsorption, and imaging techniques. The thesis has focused on preparing highly-stable MOFs for catalysis, using post-synthetic methods to modify the properties of these crystals, and applying a combination of characterization techniques to probe these complex materials. In the first part of this thesis, several new vanadium MOFs have been presented. The synthesis of MIL-88B(V), MIL-101(V), and MIL-47 were studied using ex situ techniques to gain insight into the synthesis–structure relationships. The properties of these materials have also been studied. In the second part, the use of MOFs as supports for metallic nanoparticles has been investigated. These materials, Pd@MIL-101–NH2(Cr) and Pd@MIL-88B–NH2(Cr), were used as catalysts for Suzuki–Miyaura and oxidation reactions, respectively. The effect of the base on the catalytic activity, crystallinity, porosity, and palladium distribution of Pd@MIL-101–NH2(Cr) was studied. In the final part, the introduction of transition-metal complexes into MOFs through different synthesis routes has been described. A ruthenium complex was grafted onto an aluminium MOF, MOF-253, and an iridium metallolinker was introduced into a zirconium MOF, UiO-68–2CH3. These materials were used as catalysts for alcohol oxidation and allylic alcohol isomerization, respectively.At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 5: Manuscript.
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Ryder, Matthew. "Physical phenomena in metal-organic frameworks : mechanical, vibrational, and dielectric response." Thesis, University of Oxford, 2017. https://ora.ox.ac.uk/objects/uuid:c7a51278-19d7-45ae-825a-bac8040775a7.
Повний текст джерелаАнотація:
This thesis entails the utilisation of ab initio density functional theory (DFT) in conjunction with neutron and synchrotron spectroscopy to study the mechanical, vibrational, and dielectric response of metal-organic framework (MOF) materials at the molecular level. MOFs are crystalline materials with nanoscale porosity, which have garnered immense scientific and technological interest for a wide variety of innovative engineering applications. One part of the thesis involves using low-frequency lattice vibrations to characterise the various physical motions that are possible for framework materials. These collective modes detected at terahertz (THz) frequencies have been used to reveal a broad range of exciting possibilities. New evidence has been established to demonstrate that THz modes are intrinsically linked to anomalous elasticity underpinning gate-opening and pore-breathing mechanisms, and to shear-induced phase transitions and the onset of structural instability. The phenomenon of molecular rotor mechanisms and trampoline-like motions are also observed, along with the first experimental confirmation of coordinated shear dynamics. Additionally, a new method to characterise the effects of temperature, and hence thermally-induced structural amorphisation is reported. Finally, for the first time, the frequency-dependent (dynamic) dielectric response of MOF materials, across the extended infrared (IR) spectral region was reported. The results were obtained from experimental synchrotron radiation IR reflectivity and DFT to reveal the low-к dielectric response of MOFs and established structure-property trends that highlight them as promising systems for microelectronic device applications.
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Nouar, Farid. "Design, Synthesis and Post-Synthetic Modifications of Functional Metal-Organic Materials." Scholar Commons, 2010. https://scholarcommons.usf.edu/etd/1725.
Повний текст джерелаАнотація:
Porous solids are a class of materials of high scientific and technological significance. Indeed, they have the ability to interact with atoms, ions or molecules not only at their surface but also throughout the bulk of the solid. This ability places these materials as a major class involved in many applications such as gas storage and separation, catalysis, drug delivery and sensor technology.
Metal-Organic Materials (MOMs) or coordination polymers (CPs) are crystalline compounds constructed from metal ions or clusters and organic components that are linked via coordination bonds to form zero-, one-, two or three-periodic structures. Porous Metal-Organic Materials (MOMs) or Metal-Organic Frameworks (MOFs) are a relatively new class of nanoporous materials that typically possess regular micropores stable upon removal of guests. An extraordinary academic and industrial interests was witnessed over the past two decades and is evidenced by a fantastic grow of these new materials. Indeed, due to a self-assembly process and readily available metals and organic linkers, an almost infinite number of materials can, in principle, be synthesized. However, a rational design is very challenging but not impossible. In theory, MOMs could be designed and synthesized with tuned functionalities toward specific properties that will determine their potential applications.
The present research involves the design and synthesis of functional porous Metal-Organic Materials that can be used as platforms for specific studies related to many applications such as for example gas storage and particularly hydrogen storage. In this manuscript, I will discuss the studies performed on existing major Metal-Organic Frameworks, namely Zeolite-like Metal-Organic Frameworks (ZMOFs) that were designed and synthesized in my research group. My research was also focused on the design and the synthesis of new highly porous isoreticular materials based on Metal-Organic Polyhedra (MOP) where desirable functionality and unique features can be introduced in the final material prior and/or after the assembly process. The use of hetero-functional ligands for a rational design toward binary or ternary net will also be discussed in this dissertation.
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Lifshits, Liubov Mikhaylovna. "A supramolecular approach for engineering functional solid-state chromophore arrays within metal-organic materials." Bowling Green State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1460155929.
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Das, Anita. "Metal- Organic Frameworks as a Platform for Elucidating the Effects of Functional Sites on CO2 Interaction." Thesis, The University of Sydney, 2015. http://hdl.handle.net/2123/13813.
Повний текст джерелаАнотація:
This thesis reports an investigation into metal-organic frameworks (MOFs) as candidate solid-state carbon dioxide capture materials. The modulation of CO2 uptake and heat of adsorption (|Qst|) were explored in response to the systematic variation of pore size, surface area and/or functionalisation in a range of targeted MOFs. Chapter 3 exploits ligand design and targeted MOF synthesis. Functionalised ligands based on the 4,4′-biphenyldicarboxylate core were generated through facile synthetic routes and incorporated into known MOF topologies, including the cubic UiO topology, the pillared paddlewheel topology and IRMOF-9 topology. Through the variation of metal, pore size and/or functionality in each of these series, general correlations between structure and degree of CO2 interaction with the adsorbate were elucidated. The problematic nature of unpredictable MOF self-assembly are also discussed Chapter 3, in which the synthesis, characterisation, and properties of four novel MOFs have been examined. Chapter 4 investigates post-synthetic modification (PSM) as an approach to generate more polar functional sites. PSM was undertaken in two framework types, microporous UiO-66 and mesoporous MIL-101, to investigate the effect of pore size on both the extent of PSM and its influence on CO2 uptake. In the mesoporous case, the polar functional sites increased CO2 uptake in all cases despite lower surface areas, suggesting that for larger pore frameworks, this is an effective strategy for enhancing CO2 uptake. Chapter 5 explores the potential for interplay between CO2 uptake and optical properties in MOFs through the use of CO2-reactive sites tethered to fluorophores in the porous structures. The results suggest that MOFs containing the arginine moiety are promising candidate CO2 chemosensors, as they exhibited strong linear fluorescence responses with increased CO2 dosing. This chapter presents a promising approach to the design of novel chemosensors.
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Epp, Konstantin [Verfasser], Roland A. [Akademischer Betreuer] Fischer, Vos Dirk [Gutachter] De, and Roland A. [Gutachter] Fischer. "Metalloporphyrin-based Metal-Organic Frameworks as Multi-Functional Heterogeneous Catalysts / Konstantin Epp ; Gutachter: Dirk De Vos, Roland A. Fischer ; Betreuer: Roland A. Fischer." München : Universitätsbibliothek der TU München, 2019. http://d-nb.info/1188408879/34.
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Penley, Drace Robert. "Multi-Layer Connectivity-Based Atom Contribution Method for Charge Assignments in Metal-Organic Frameworks (MOFs)." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1555599813789541.
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Elsaidi, Sameh Khamis. "Crystal Engineering of Functional Metal-Organic Material Platforms for Gas Storage and Separation Applications." Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/5417.
Повний текст джерелаАнотація:
Metal-organic materials (MOMs) represent a unique class of porous materials that captured a great scientific interest in various fields such as chemical engineering, physics and materials science. They are typically assembled from metal ions or metal clusters connected by multifunctional organic ligands. They represent a wide range of families of materials that varied from 0D to 3D networks: the discrete (0D) structures exemplified by metal-organic polyhedra (MOPs), cubes and nanoballs while the polymeric 1D, 2D and 3D structures exemplified by coordination polymers (CPs). Indeed, the porous 3D structures include metal-organic frameworks (MOFs), porous coordination polymers (PCPs) and porous coordination networks (PCNs). Nevertheless, MOMs are long and well-known from more than 50 years ago as exemplified by CPs that were firstly introduced in early 1960s and reviewed in 1964. However, the scientific interest toward MOMs has been enormously grown only since late 1990s, with the discovery of MOMs with novel properties, especially the high permanent porosity as exemplified by MOF-5 and HKUST-1. The inherent tunability of MOMs from the de novo design to the post-synthetic modification along with their robustness, afford numerous important families of nets "platforms" such as pcu, dia, tbo, mtn and rht topology networks.
There are more than 20,000 crystal structures of MOMs in the Cambridge Structure Database (CSD). However, only a few of the networks can be regarded as families or platforms where the structure is robust, fine-tunable and inherently modular. Such robustness and inherent modularity of the platforms allow the bottom-up control over the structure "form comes before function" which subsequently facilitates the systematic study of structure/function in hitherto unprecedented way compared with the traditional screening approaches that are commonly used in materials science. In this context, we present the crystal engineering of two MOM platforms; dia and novel fsc platforms as well we introduce the novel two-step synthetic approach using trigonal prismatic clusters to build multinodal 2D and 3D MOM platforms.
For the dia platform, we introduce a novel strategy to control over the level of the interpenetration of dia topology nets via solvent-template control and study the impact of the resulting different pore sizes on the squeezing of CH4, CO2 and H2 gases. New benchmark material for methane isosteric heat of adsorption was produced from this novel work.
Indeed we introduce the crystal engineering of a novel versatile 4,6-c fsc platform that is formed from linking two of the longest known and most widely studied MBBs: the square planar MBB [Cu(AN)4]2+( AN = aromatic nitrogen donor) and square paddlewheel MBB [Cu2(CO2R)4] that are connected by five different linkers with different length, L1-L5. The resulting square grid nets formed from alternating [Cu(AN)4]2+ and [Cu2(CO2R)4] moieties are pillared at the axial sites of the [Cu(AN)4]2+ MBBs with dianionic pillars to form neutral 3D 4,6-connected fsc (four, six type c) nets. Pore size control in this family of fsc nets was exerted by varying the length of the linker ligand whereas pore chemistry was implemented by unsaturated metal centers (UMCs) and the use of either inorganic or organic pillars. 1,5-naphthalenedisulfonate (NDS) anions pillar in an angular fashion to afford fsc-1-NDS, fsc-2-NDS, fsc-3-NDS, fsc-4-NDS and fsc-5-NDS from L1-L5, respectively. Experimental CO2 sorption studies revealed higher isosteric heat of adsorption (Qst) for the compound with the smaller pore size (fsc-1-NDS). Computational studies revealed that there is higher CO2 occupancy about the UMCs in fsc-1-NDS compared to other extended variants that were synthesized with NDS. SiF62- (SIFSIX) anions in fsc-2-SIFSIX form linear pillars that result in eclipse [Cu2(CO2R)4] moieties at a distance of just 5.86 Å. The space between the [Cu2(CO2R)4] moieties is a strong CO2 binding site that can be regarded as being an example of a single-molecule trap; this finding has been supported by modeling studies.
Furthermore, we present herein the implementation of the two-step synthetic approach for the construction of novel multinodal MOM platforms, using the trigonal prism cluster [M3(µ3-O)(RCO2)6] as a precursor to build novel stable multinodal 2D and 3D frameworks. In the first step, the bifunctional carboxylate ligands are reacted with Fe+3 or Cr+3 salts to isolate highly symmetrical decorated trigonal prismatic clusters with diverse decoration such as pyridine, amine and cyano coordinating functional groups using pyridine carboxylate, amino carboxylate, cyano carboxylate type ligands, respectively. Afterward, the isolated highly soluble trigonal prismatic salts were reacted in the second step with another metal that can act as node or linker to connect the discrete trigonal prismatic clusters to build 2D or 3D networks. Indeed, we were able to develop another novel high-symmetry Cu cluster [Cu3(µ3-Cl)(RNH2)6Cl6] by utilizing CuCl2 salt and amine decorated trigonal prismatic cluster. Two novel 3D water stable frameworks with acs and stp topologies have been afforded.
Our work on the crystal engineering design and synthesis of new MOM platforms offer an exceptional level of control over the resulting structure including; the resulting topology, pore size, pore chemistry and thereby enable the control over the resulting physicochemical properties in a manner that facilitates the achieving of the desired properties.
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Cliffe, Matthew James. "Disorder and defects in functional molecular frameworks." Thesis, University of Oxford, 2015. http://ora.ox.ac.uk/objects/uuid:cd827bc8-b3dd-4fda-bdb8-f0dc893d66c2.
Повний текст джерелаАнотація:
This Thesis explores the role of structural defects and disorder and their relationship to experimental data, with a particular emphasis on molecular framework materials. The question of how we can build atomistic models of amorphous materials from experimental data without needing to make system-specific assumptions is addressed. The role of 'structural invariance', i.e. the limited range of distinct local atomic environments within a material, as a restraint within reverse Monte Carlo refinement (RMC) is investigated. The operation of these invariance restraints operate is shown to be system-dependent and the challenges associated with effective refinement, e.g. configurational 'jamming', are also investigated. A generalisation to the 'structural simplicity', i.e. the simplest model, holding all else constant, is most likely to be correct. Three new metrics of structural simplicity are proposed: two intrinsically three-dimensional measures of local geometric invariance and one measure of local symmetry. These metrics are shown to robustly quantify the configurational quality. The ability of these metrics to act as effective restraints for the RMC refinement of amorphous materials is demonstrated by the construction of the first data-driven tetrahedral models of amorphous silicon. The role of defects and disorder within metal–organic frameworks (MOFs) is investigated through the canonical MOF UiO-66(Hf). Through a combination of techniques, including X-ray diffuse scattering, anomalous diffraction, total scattering and electron diffraction measurements, the existence of correlated metal-cluster absences in UiO-66(Hf) is demonstrated. Furthermore the ability to synthetically tune both the interactions and concentration of defects is shown. The thermomechanical properties of defective UiO-66(Hf) are also examined. UiO-66(Hf) is shown to rapidly densify by up to 5% (ΔV/V ) on ligand elimination. The resultant densified phase exhibits colossal (≥100MK-1) volumetric negative thermal expansion (NTE); the largest reported value for any MOF. Finally, the capability to tune the physical properties of MOFs through defect incorporation is demonstrated through the defect-dependence of both the densification and the NTE.
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Cairns, Amy J. "Structural Diversity in Crystal Chemistry: Rational Design Strategies Toward the Synthesis of Functional Metal-Organic Materials." Scholar Commons, 2010. http://scholarcommons.usf.edu/etd/3455.
Повний текст джерелаАнотація:
Metal-Organic Materials (MOMs) represent an important class of solid-state crystalline materials. Their countless attractive attributes make them uniquely suited to potentially resolve many present and future utilitarian societal challenges ranging from energy and the environment, all the way to include biology and medicine. Since the birth of coordination chemistry, the self-assembly of organic molecules with metal ions has produced a plethora of simple and complex architectures, many of which possess diverse pore and channel systems in a periodic array. In its infancy however this field was primarily fueled by burgeoning serendipitous discoveries, with no regard to a rational design approach to synthesis.
In the late 1980s, the field was transformed when the potential for design was introduced through the seminal studies conducted by Hoskins and Robson who transcended the pivotal works of Wells into the experimental regime. The construction of MOMs using metal-ligand directed assembly is often regarded as the origin of the molecular building block (MBB) approach, a rational design strategy that focuses on the self-assembly of pre-designed MBBs having desired shapes and geometries to generate structures with intended topologies by exploiting the diverse coordination modes and geometries afforded by metal ions and organic molecules.
The evolution of the MBB approach has witnessed tremendous breakthroughs in terms of scale and porosity by simply replacing single metal ions with more rigid inorganic metal clusters whilst preserving the inherent modularity and essential geometrical attributes needed to construct target networks for desired applications. The work presented in this dissertation focuses upon the rational design and synthesis of a diverse collection of open frameworks constructed from pre-fabricated rigid inorganic MBBs (i.e. [M(CO2)4], [M2(RCO2)4], [M3O(RCO2)6], MN3O3, etc), supermolecular building blocks (SBBs) and 3-, 4- and 6-connected organic MBBs. A systematic evaluation concerning the effect of various structural parameters (i.e. pore size and shape, metal ion, charge, etc) on hydrogen uptake and the relative binding affinity of H2-MOF interactions for selected systems is provided.
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Sava, Dorina F. "Quest Towards the Design and Synthesis of Functional Metal-Organic Materials: A Molecular Building Block Approach." Scholar Commons, 2009. https://scholarcommons.usf.edu/etd/5.
Повний текст джерелаАнотація:
The design of functional materials for specific applications has been an ongoing challenge for scientists aiming to resolve present and future societal needs. A burgeoning interest was awarded to developing methods for the design and synthesis of hybrid materials, which encompass superior functionality via their multi-component system. In this context, Metal-Organic Materials (MOMs) are nominated as a new generation of crystalline solid-state materials, proven to provide attractive features in terms of tunability and versatility in the synthesis process. In strong correlation with their structure, their functions are related to numerous attractive features, with emphasis on gas storage related applications.
Throughout the past decade, several design approaches have been systematically developed for the synthesis of MOMs. Their construction from building blocks has facilitated the process of rational design and has set necessary conditions for the assembly of intended networks.
Herein, the focus is on utilizing the single-metal-ion based Molecular Building Block (MBB) approach to construct frameworks assembled from predetermined MBBs of the type MNx(CO2)y. These MBBs are derived from multifunctional organic ligands that have at least one N- and O- heterochelate function and which possess the capability to fully saturate the coordination sphere of a single-metal-ion (of 6- or higher coordination number), ensuring rigidity and directionality in the resulting MBBs. Ultimately, the target is on deriving rigid and directional MBBs that can be regarded as Tetrahedral Building Units (TBUs), which in conjunction with appropriate heterofunctional angular ligands are capable to facilitate the construction of Zeolite-like Metal-Organic Frameworks (ZMOFs). ZMOFs represent a unique subset of MOMs, particularly attractive due to their potential for numerous applications, arising from their fully exploitable large and extra-large cavities.
The research studies highlighted in this dissertation will probe the validity and versatility of the single-metal-ion-based MBB approach to generate a repertoire of intended MOMs, ZMOFs, as well as novel functional materials constructed from heterochelating bridging ligands. Emphasis will be put on investigating the structure-function relationship in MOMs synthesized via this approach; hydrogen and CO2 sorption studies, ion exchange, guest sensing, encapsulation of molecules, and magnetic measurements will be evaluated.
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Yadnum, Sudarat. "Tailoring complex heterogeneous metal-organic framework structures." Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0299/document.
Повний текст джерелаАнотація:
Dans cette thèse, de nouvelles stratégies pour la préparation de matériaux de type Metal-Organic-Frameworks (MOF) ont été étudiés et développés. L’électrodeposition bipolaire indirecte (IBED) a été utilisé pour préparer ZIF-8 et HKUST-1 sur des substrats métalliques de façon simple et avec une sélectivité spatiale. Ce concept devrait pouvoir être généralisée pour la synthèse de nombreux autres composés MOF, permettant ainsi une synthèse pas chère et verte, conduisant à de nouvelles générations de composites de type Janus basés sur des MOFs. En outre, des électrodes avec une structure hiérarchique macro-/ microporeux de HKUST-1 ont été préparées par une technique de dissolution-dépôt électrochimique. L'approche de synthèse mis au point est très pratique en ce qui concerne la durée des expériences, et ouvre diverses applications pour les MOFs. Enfin des nanoparticules de métaux nobles sur un substrat à base de MIL-101 ont été préparées comme la dernière partie de l'étude expérimentale par dépôt colloïdal. Ce concept peut être généralisé pour la synthèse d'autres composites nanoparticules métalliques / MOF, et pourrait améliorer l'activité catalytique des MOFs. En dehors de l'étude expérimentale, afin de comprendre mieux la catalyse de matériaux MOF, le comportement catalytique de Cu (II) dans le MOF-505 a été théoriquement étudié pour la réaction d'aldolisation Mukayiama par la théorie de densité fonctionnelle et comparé à celui d'un autre catalyseur, Cu-ZSM-5. En outre, le comportement catalytique d'amas homo- et hétéro-bimétalliques, qui sont des complexes métalliques qui représentent les agrégats métalliques dans les MOFs, a également été étudié théoriquement pour la réaction de cycloaddition de dioxyde de carbone et des oxydes d'éthylèneIn this thesis, new strategies for the preparation of Metal 0rganic Frameworks (MOF) materials with designed structures were studied and developed. Indirect bipolar electrodeposition (IBED) was used to prepare ZIF-8 and HKUST-1 on metal substrates in a straightforward and site-selective way. This concept is expected to be able to be generalized for the synthesis of many other MOF compounds, thus allowing a cheap and green synthesis, leading to new generations of MOF-based Janus-type composites. Furthermore, rationally designed hierarchical macro-/microporous HKUST-1 electrodes were prepared via an electrochemical dissolution-deposition technique. The developed synthesis approach is very practical in terms of the time consumption, and opens up MOFs for various applications. Finally, MIL-101-supported noble metal nanoparticles were prepared as the last part of the experimental studies via a simple colloidal deposition technique. This concept might be generalized for the synthesis of other metal nanoparticle/MOF composites, and might improve the catalytic activity of MOFs. Apart from the experimental study, in order to gain a deeper insight into the catalysis of MOF materials, the catalytic behavior of Cu(II) in the paddle-wheel unit of MOF-505 was theoretically investigated for the Mukaiyama aldol reaction via the density functional theory and compared to that of another catalyst, Cu-ZSM-5 zeolite. Besides, the catalytic behavior of homo-metallic clusters and hetero-bimetallic clusters, that are the metal complexes representing the metal clusters in MOFs, were also theoretically investigated for the cycloaddition reaction of carbon dioxide and ethylene oxides
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Salomon, William. "Incorporation de polyoxométallates dans des matériaux hybrides de type MOFs pour des applications en magnétisme et en électrocatalyse." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLV124/document.
Повний текст джерелаАнотація:
Différents matériaux hybrides à base de polyoxométallates (POMs) ont été synthétisés au cours de cette thèse. Dans un premier type de matériaux, appelé POM@MOF, des POMs sont incorporés au sein des cavités poreuses d'un Metal-Organic-Framework (MOF). Ces matériaux ont été synthétisés par une méthode d'imprégnation en milieu aqueux ou par synthèse directe en conditions solvothermales. Ils ont ensuite été caractérisés de manière approfondie. La stabilité ou l'évolution des polyoxométallates lors de l'incorporation dans le MOF étant chaque fois parfaitement établie. Les matériaux POM@MOFs ont ensuite été étudiés pour leurs applications en magnétisme, pour la détection et en catalyse. Dans un second temps, des polymère de coordination hybrides à base de POMs (surnomés POMOFs) construits à partir d'isomères ε-Keggin reliés par des ligands organiques ont été synthétisés par voie hydrothermale. De nouvelles structures POMOFs ont pu être obtenue en présence de POMs, de ligands carboxylates et de complexes métalliques comme contre-ions non-innocents. L'activité de ces matériaux vis-à-vis de la réduction des protons a été étudiée par électrocatalyse et photocatalyse. Parallèlement, des synthèses de composés moléculaires solubles à base de POMs ε-Keggin ont également été réalisées. Finalement, des espèces hybrides incorporant des métaux de transitions et des ligands bisphosphonates ont été synthétisées : des polymères incorporant du cuivre(II) et un composé moléculaire à base fer(III). Ces espèces ont ensuite été étudiées pour leurs propriétés magnétiques, catalytiques pour la réduction des NOx. L'espèce à base de fer a également été sélectionnée comme substrat pour des études de dépôt sur surface de siliceDifferent Polyoxometalate (POM) based hybrid materials were synthesised during this doctorate. In the first type of materials, called POM@MOF, POMs are incorporated in the porous cavities of a Metal-Organic-Framework (MOF). These materials were synthesised by a impregnation method in an aqueous medium or by direct synthesis in solvothermal conditions. They were then extensively characterised. For every material, the stability or transformation of the POMs during the incorporation was accurately established. The POM@MOFs materials were then studied for their applications in magnetism, for detection and in catalysis. In a second time, POM-based hybrid coordination polymers (called POMOFs) made from ε-Keggin isomers connected by organic linkers were synthesised by a hydrothermal method. New POMOFs structures have been obtained with POMs, carboxylate linkers and metallic complexes as non-innocents counter ions. The catalytic activity of these materials toward protons reduction was studied by electrocatalysis and photocatalysis. In parallel, syntheses of soluble molecular compounds based on ε-Keggin POMs were also performed. Finally, hybrid species incorporating transition metals and bisphosphonate linkers were synthesised : three copper(II) based polymers and a molecular coumpound incorporating iron(III). The magnetic and catalytic (reduction of NOx) properties of these materials were then studied. The iron based species was also selected as substrate for the deposition on a silica surface
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Schoedel, Alexander. "[M3(μ3-O)(O2CR)6] and Related Trigonal Prisms: Versatile Molecular Building Blocks for 2-Step Crystal Engineering of Functional Metal-Organic Materials". Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/5121.
Повний текст джерелаАнотація:
Metal-organic materials (MOMs) assembled from metal-based building blocks and organic linkers have attracted much interest due to their large pore dimensions and their enormous structural diversity. In comparison to their inorganic counterparts (zeolites), these crystalline materials can be easily modified to tailor pore dimensions and functionality for specifically targeted properties.
The work presented herein encompasses the development of a synthetic 2-step process for the construction of novel families of MOMs or 'platforms' and allow us exquisite design and control over the resulting network topologies. Examples of cationic mesoporous structures were initially exploited, containing carboxylate based centers connected by metal-pyridine bonds. The inherently cationic nets allowed for subsequent anion exchange which can be regarded as an elegant and easy postsynthetic modification strategy. The incorporation of different functionalities inside the channels of the networks was then demonstrated as useful in terms of carbon dioxide capture.
The scope of the 2-step process was then expanded to construction of the first trinodal MOM platform involving triangular, tetrahedral and trigonal prismatic building units: tp-PMBB-1-asc. Examples of reticular chemistry are shown which enable the formation of large and functionalized nanocages with retention of the underlying network topology. Gas adsorption studies indicate relatively high uptakes of carbon dioxide and hydrogen which, together with the use of inexpensive ligands, provide an excellent cost/performance ratio of these materials. Moreover, very high stability in organic solvents and especially in water are addressed which is a particularly challenging, but industrially relevant target in the field of Metal-Organic Materials.
The 2-step approach was also used to synthesize a new and versatile class of metal-organic materials with augmented lonsdaleite-e (lon-e-a) topology. This family of lon-e nets is built by pillaring of hexagonal 2-dimensional kagomé (kag) lattices that are in turn pillared by a trigonal prismatic Primary Molecular Building Block (tp-PMBB-1). These MOMs represent the first examples of axial-to-axial-pillared undulating kag layers and they are readily fine-tuned because the bdc2- moieties can be varied at their 5-position without changing the overall structure. This lon-e platform possesses functionalized hexagonal channels since the kag lattices are necessarily eclipsed. The effect of the substituent at the 5-positions of the bdc2- linkers upon gas adsorption, particularly the heats of adsorption of carbon dioxide and methane, were studied.
If linear dicarboxylates were instead utilized, we were able to synthesize a new and versatile class of metal-organic materials that exhibits 4,6-connected fsb topology. These networks are constructed from simple and inexpensive building units and since interpenetration is precluded, afford very high void volumes. They therefore represent ideal targets to generate a novel family of frameworks, because of the ready availability functionalized and expanded ligand derivatives. They also allow for systematic fine tuning and could ultimately provide a roadmap to ultra-high surface areas from simple building blocks.
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Khaletskaya, Kira [Verfasser], Roland A. [Gutachter] Fischer, and Tendeloo Gustaaf [Gutachter] Van. "Functional metal-organic frameworks : from bulk to surface engineered properties / Kira Khaletskaya ; Gutachter: Roland A. Fischer, Gustaaf Van Tendeloo ; Fakultät für Chemie und Biochemie." Bochum : Ruhr-Universität Bochum, 2015. http://d-nb.info/1227707568/34.
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Mayer, David Christian [Verfasser], Roland A. [Akademischer Betreuer] Fischer, Roland A. [Gutachter] Fischer, Jürgen [Gutachter] Hauer, and Christof [Gutachter] Wöll. "Contributions to Multi-Photon Absorption in Metal-Organic Frameworks / David Christian Mayer ; Gutachter: Roland A. Fischer, Jürgen Hauer, Christof Wöll ; Betreuer: Roland A. Fischer." München : Universitätsbibliothek der TU München, 2020. http://d-nb.info/1224047052/34.
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Hante, Inke [Verfasser], Roland A. [Gutachter] Fischer, and Shin-ichiro [Gutachter] Noro. "Functional metal-organic frameworks : targeted design and modification of advanced properties of MOFs \(\it via\) organic linker funcionalisation / Inke Hante ; Gutachter: Roland A. Fischer, Shin-ichiro Noro ; Fakultät für Chemie und Biochemie." Bochum : Ruhr-Universität Bochum, 2017. http://d-nb.info/1150509422/34.
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Kozachuk, Olesia [Verfasser], Roland A. [Gutachter] Fischer, and Martin [Gutachter] Muhler. "Advanced functional materials based on metal-organic frameworks : elaboration of redox-active & mixed-component "defekt engineered" MOFs / Olesia Kozachuk ; Gutachter: Roland A. Fischer, Martin Muhler ; Fakultät für Chemie und Biochemie." Bochum : Ruhr-Universität Bochum, 2014. http://d-nb.info/1231542330/34.
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Schneider, Christian [Verfasser], Roland A. [Akademischer Betreuer] Fischer, Thomas [Gutachter] Weitz, Mark D. [Gutachter] Allendorf, and Roland A. [Gutachter] Fischer. "Retrofitting Metal-Organic Frameworks : TCNQCu3BTC2 as a Case Study for Functional Material Design / Christian Schneider ; Gutachter: Thomas Weitz, Mark D. Allendorf, Roland A. Fischer ; Betreuer: Roland A. Fischer." München : Universitätsbibliothek der TU München, 2019. http://d-nb.info/120329994X/34.
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Schneider, Christian Verfasser], Roland A. [Akademischer Betreuer] [Fischer, Thomas Gutachter] Weitz, Mark D. [Gutachter] [Allendorf, and Roland A. [Gutachter] Fischer. "Retrofitting Metal-Organic Frameworks : TCNQCu3BTC2 as a Case Study for Functional Material Design / Christian Schneider ; Gutachter: Thomas Weitz, Mark D. Allendorf, Roland A. Fischer ; Betreuer: Roland A. Fischer." München : Universitätsbibliothek der TU München, 2019. http://nbn-resolving.de/urn:nbn:de:bvb:91-diss-20190807-1516469-1-8.
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Schneider, Christian Verfasser], Roland A. [Akademischer Betreuer] Fischer, Thomas [Gutachter] Weitz, Mark D. [Gutachter] [Allendorf, and Roland A. [Gutachter] Fischer. "Retrofitting Metal-Organic Frameworks : TCNQCu3BTC2 as a Case Study for Functional Material Design / Christian Schneider ; Gutachter: Thomas Weitz, Mark D. Allendorf, Roland A. Fischer ; Betreuer: Roland A. Fischer." München : Universitätsbibliothek der TU München, 2019. http://d-nb.info/120329994X/34.
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Cragg-Hine, Ian. "Early main group metal complexes of multi-functional organic molecules." Thesis, University of Cambridge, 1995. https://www.repository.cam.ac.uk/handle/1810/271932.
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Eubank, Jarrod F. "Rational synthesis toward the design of functional metal-organic materials." [Tampa, Fla] : University of South Florida, 2008. http://purl.fcla.edu/usf/dc/et/SFE0002408.
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Tu, Min [Verfasser], Roland A. [Akademischer Betreuer] Fischer, and Mark D. [Akademischer Betreuer] Allendorf. "Engineering functional metal-organic framework thin film devices / Min Tu. Gutachter: Roland A. Fischer ; Mark D. Allendorf." Bochum : Ruhr-Universität Bochum, 2016. http://d-nb.info/1095884514/34.
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Mohebbi, Elaheh. "Surface supported supramolecular architectures: an experimental and modeling study." Doctoral thesis, Università degli studi di Padova, 2019. http://hdl.handle.net/11577/3427304.
Повний текст джерелаАнотація:
L’auto-organizzazione di molecole organiche su superfici solide è uno degli approcci più diffusi per la creazione di architetture supramolecolari supportate di dimensioni controllate e con proprietà innovative. L’uso combinato di differenti interazioni di natura non covalente adsorbato–adsorbato e adsorbato–substrato consente infatti la modulazione dell’associazione di specie distinte in modo quasi altrettanto accurato che nei sistemi biologici, fonte primaria di ispirazione per ciò che può essere realizzato artificialmente. Il consenso sull’uso d’interazioni intermolecolari estese non covalenti nell’ingegnerizzazione di nanostrutture bidimensionali supportate prive di difetti è unanime. Ciononostante, i materiali così ottenuti sono spesso fragili, incapaci di resistere a condizioni aggressive, privi di stabilità meccanica ed inefficienti nei processi di trasferimento di carica intermolecolare; sono cioè materiali inadatti per applicazioni tecnologiche. La produzione di sistemi nanostrutturati supportati con proprietà predeterminate, privi di difetti e con risvolti applicativi implica quindi la sintesi di network covalenti robusti, non caratterizzati dalle limitazioni di cui sopra. In questa tesi di dottorato si è voluta esplorare sia sperimentalmente sia teoricamente la possibilità di stabilizzare covalentemente network supramolecolari funzionali in una/due dimensioni stimolando la formazione di legami covalenti tra molecole preorganizzate su una superficie.The scientific community is nowadays focused on the design and the production of nm/μm-sized systems for their relevance to nanotechnology, energy production and storage, life science and environment. Advances in high performing computing and in synthetic/characterization methods make possible devising novel rational approaches to tailor properties of low-dimensional architectures of molecular networks on inorganic substrates; i.e., to control the electron transport properties of active layers and the reactivity of selected sites. As such, the self-assembly of functional architectures on appropriate surfaces is the most promising bottom-up approach to organize and integrate single molecules on solid substrates. As a consequence of the persistent progress in computational power and multiscale material modeling, new materials are less likely to be discovered by a trial-and-error approach. This points to a paradigm shift in modeling, away from reproducing known properties of known materials and towards simulating the properties of hypothetical composites as a forerunner to get real materials with desired characteristics. The interplay among multiscale material modeling, new synthetic routes and appropriate validation experiments is crucial to design the desired behavior at each length scale. In this PhD thesis we exploited integrated methodologies to provide interpretative tools about structure and functions of organic/inorganic hybrid nanostructured materials made of molecular mono-layers deposited on technological relevant substrates, suitable for applications in strategic areas such as catalysis, artificial photosynthesis, molecular electronics-magnetism and molecular recognition.
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Bétard, Angélique [Verfasser], Roland A. [Gutachter] Fischer, and Nils [Gutachter] Metzler-Nolte. "Growth and chemistry of metal-organic framework thin films : toward functional coatings / Angélique Bétard ; Gutachter: Roland A. Fischer, Nils Metzler-Nolte ; Fakultät für Chemie und Biochemie." Bochum : Ruhr-Universität Bochum, 2013. http://d-nb.info/1201551463/34.
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Dawson, Daniel M. "Combined theoretical and experimental investigations of porous crystalline materials." Thesis, University of St Andrews, 2014. http://hdl.handle.net/10023/7053.
Повний текст джерелаАнотація:
This thesis combines solid-state nuclear magnetic resonance (NMR) spectroscopy, X-ray diffraction (XRD), chemical synthesis, isotopic enrichment and density-functional theory (DFT) calculations to provide insight into a number of microporous materials. The first class of materials studied is metal-organic frameworks (MOFs), where the presence of paramagnetic ions has a range of effects on the ¹³C NMR spectra, depending on the nature of the ligand-metal interactions. For the Cu²⁺-based MOFs, HKUST-1 and STAM-1, the assignment of the NMR spectra is non-intuitive, and unambiguous assignment requires specific ¹³C labelling of the organic linker species. It is shown that ¹³C NMR spectra of these two MOFs could act as a sensitive probe of the nature of “guest” molecules bound to the Cu²⁺. The second class of materials is aluminophosphates (AlPOs). It is shown that, using a series of relatively simple linear relationships with the crystal structure, the NMR parameters calculated by DFT (with calculation times of several hours) can be predicted, often with experimentally-useful accuracy, in a matter of seconds using the DIStortion analysis COde (DISCO), which is introduced here. The ambient hydration of the AlPO, JDF-2, to AlPO-53(A) is shown to occur slowly, with incomplete hydration after ~3 months. The resulting AlPO-53(A) is disordered and some possible models for this disorder are investigated by DFT. The final class of materials is gallophosphates (GaPOs), particularly GaPO-34 and related materials. The two as-prepared forms of GaPO-34 are characterised by solid-state NMR, and their calcination investigated by TGA and in-situ powder XRD. An unusual dehydrofluorinated intermediate phase is isolated and characterised for the first time by solid-state NMR. The fully calcined material is shown to be stable under anhydrous conditions, but hydrates rapidly in air. The hydrated material is stable under ambient conditions, but collapses upon heating. Partial dehydration without collapse is achieved by gentle heating or room-temperature evacuation. The impurity phases, GaPO₄ berlinite and GaPO-X are investigated by solid-state NMR and, while the structure of GaPO-X remains unknown, much structural information is obtained.
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Li, Pei-Syuan, and 李佩璇. "Synthesis of Isostructural Metal-Organic Frameworks with Various Metal and Functional Groups." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/m5b8e5.
Повний текст джерелаАнотація:
碩士中原大學
化學研究所
102
In section one, isostructural synthesis and ligand-fuctinonalization are used as strategies for the solvothermal reactions of two porous metal-organic framework (MOFs) of [Zr(OH)(SDC)] (1) and [Zr(OH)(NO2-SDC)] (2) (H2SDC = 4,4'- stilbenedicarboxylic acid; NO2-H2SDC = 2,2'-dinitro-4,4'- stilbenedicarboxylic acid). In section two, the isostructural solvothermal reactions of benzenedicarboxylic acid (H2BDC) and 2-aminoterephthalic acid (NH2-H2BDC) are achieved by different ratios of NH2-H2BDC/H2BDC (0%、12.5%、25%、50%) and trivalent metal (M3+) ions. The series of products of 3 to 5 are listed as follows: NH2-MIL-68(Al)…………...........(3) NH2-MIL-68(Ga)…………..........(4) NH2-MIL-68(V)…………............(5) These MOFs have been characterized by the powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR), ultraviolet-visible spectrometer (UV-vis), thermogravimetric analysis (TGA), scanning electron microscopy (SEM),Photoluminescence (PL)and gas sorption measurements. The N2 adsorption and surface areas are decreased when substituted functional groups were added. The CO2 adsorption are increasing when nitro and amine functional groups were introduced. These may contributed by the better physical adsorption interactions from the functional groups.
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Chen, Chih-Wei, and 陳智偉. "Synthesis of Isostructural Metal-Organic Frameworks with Nitro Functional Groups." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/12292582280616526840.
Повний текст джерелаАнотація:
碩士中原大學
化學研究所
104
In this study, four series of metal-organic frameworks (MOFs) were synthesized by the reactions of mixed organic ligands and trivalent metal (M3+) ions. The mixed organic ligands contain benzenedicarboxylic acid (H2BDC) and 2-nitroterephthalic acid (NO2-H2BDC) with various ratio of NO2-H2BDC/H2BDC by 0%, 10%, 30% and 50%. The presented chemical formula of four series are listed as follows: NO2-MIL68 (Al)……………………(1) NO2-MIL68 (Ga)……………………(2) NO2-MIL68 (In) ……………………(3) NO2-MIL68 (V) .……………………(4) These MOFs were further characterized by powder X-ray diffraction (PXRD) for structure verify, Field Emission Scanning Electron Microscope (FESEM) for shapes and particle sizes, Infrared Spectrum for functional groups and gas adsorption instrument for gas adsorptions.
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Thiam, Zeynabou. "Functional Metal Organic Frameworks for Surface Organometallic Chemistry and Carbon Conversion." Diss., 2021. http://hdl.handle.net/10754/669735.
Повний текст джерелаАнотація:
Abstract: Metal-Organic Frameworks (MOFs) are a class of highly porous, hybrid, functional and crystalline extended coordination compounds. Their exceptional properties renders them ideal for a wide range of applications including gas storage and catalysis. Especially for catalysis, MOFs are receiving attention as well-defined supports for organometallic heterogeneous catalysis with noticeably the post-synthetic grafting of transition metal complexes on secondary building units (SBU) containing hydroxides moieties. The objective of this dissertation is to explore the synthesis, reactivity and functionalization of MOFs with SBU containing hydroxides units by transition metal catalyst using the Surface Organometallic Chemistry (SOMC) approach.
Chapter 1, gives an introduction to the field of MOF and their applications to catalysis through the functionalization of hydroxide containing SBUs. This chapter introduces also the SOMC strategy with an overview of its catalytic application for olefin metathesis and CO2 conversion.
Chapter 2 and 3 give a detailed application of SOMC to MOFs with the selective grafting of the W(≡CtBu)(CH2tBu)3 complex on the highly crystalline and mesoporous Zr-NU-1000 MOF. The obtained single site material, Zr-Nu-1000-W, is fully characterized using state of the art experimental methods and all the steps leading to the final grafted moieties were identified by DFT. Zr-NU-1000-W is active for olefin metathesis and is further fine-tuned by activation with EtAlCl2 giving a more selective and stable catalyst. Moreover, the nature of the grafted species could be modulated by pre-activation of the initial
W(≡CtBu)(CH2tBu)3 complex with dmpe giving W(≡CtBu)(=CHtBu)(CH2tBu)(dmpe) also grafted on Zr-NU-1000.
Chapter 4 and 5, describe the deliberate design and bulk synthesis of a new zirconium MOF, Zr-she-MOF-2, and highlight the discovery of a new highly connected MOF, RE-urx-MOF-1, based on a careful combination of rare earth (RE) metals with heterobifunctional triangular tetrazolate-based ligand. Additionally, the replacement of the tetrazolate functionality by carboxylate, leads to the formation of a different MOF structure RE-gea-MOF-4 having the gea topology with the presence of 18-connected nonanuclear RE cluster. Both Zr-she-MOF-2 and RE-gea-MOF-4 are active for the coupling of epoxides with CO2 to form cyclic carbonate in the presence of Bu4NBr.
Finally, Chapter 6 will discuss the conclusions and perspectives of this dissertation.
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C, Atzori. "Novel Ce3+ and Ce4+ Metal-Organic Frameworks: a multi-technique characterization." Doctoral thesis, 2018. http://hdl.handle.net/2318/1692942.
Повний текст джерелаАнотація:
The present thesis concerns the core activities of my three years of PhD studies: the synthesis of novel Metal-Organic Frameworks (MOFs) and their characterization using a multi-technique approach. The activities of my laboratory (NIS center at the Università di Torino) are focused on the characterization of materials and their surfaces using a wide range of techniques, mainly spectroscopies. In order to develop the synthetic skills required for the present research I spent a period of 3 months abroad in the laboratory of Prof. Stock in Kiel (Germany), whose research interests are mainly devoted to synthesis of new MOFs. The skills acquired in that period were applied to the development of the synthetic procedure of each material reported in the present document. The “trait d’union” of this thesis is the use of cerium cations in Metal-Organic Frameworks. This metal, albeit uncommon in the current MOF literature, is characterized by a high availability and a peculiar chemistry which permitted to obtain equally peculiar MOF compounds. The following work is articulated into: 1) Introduction section, where MOFs will be described in general together with the main synthetic methods and characterization techniques used in the field and a fast survey on the main applications where MOFs play a role; 2) Synthetic procedures and Experimental methods; 3) Results presented in four different sections, each one devoted to a different material; 4) Conclusions.
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Gagnon, Kevin James. "Crystalline Metal-Organic Frameworks Based on Conformationally Flexible Phosphonic Acids." Thesis, 2013. http://hdl.handle.net/1969.1/151137.
Повний текст джерелаАнотація:
The goal of the work described in this dissertation was to investigate the structure of metal phosphonate frameworks which were composed of conforma-tionally flexible ligands. This goal was achieved through investigating new syn-thetic techniques, systematically changing structural aspects (i.e. chain length), and conducting in situ X-ray diffraction experiments under non-ambient condi-tions. First, the use of ionic liquids in the synthesis of metal phosphonates was in-vestigated. Reaction systems which had previously been studied in purely aqueous synthetic media were reinvestigated with the addition of a hydrophobic ionic liq-uid to the reaction. Second, the structural diversity of zinc alkylbisphosphonates was investigated through systematically varying the chain length and reaction conditions. Last, the structural changes associated with externally applied stimuli (namely temperature and pressure) on conformationally flexible metal phospho-nates were investigated. Elevated temperature was used to investigate the structur-al changes of a 1-D cobalt chain compound through three stages of dehydration and also applied pressures of up to 10 GPa were used to probe the structural resili-ence of two zinc alkylbisphosphonate materials under.
The iminobis(methylphosphonic acid) type ligands are a good example of a small, simple, conformationally flexible ligand. There are three distinct different structural types, utilizing this ligand with cobalt metal, described in the literature, all of which contain bound or solvated water molecules. The addition of a hydrophobic ionic liquid to an aqueous synthesis medium resulted in new anhydrous compounds with unique structural features.
Systematic investigations of zinc alkylbisphosphonate materials, construct-ed with three to six carbon linker ligands, resulted in four new families of com-pounds. Each of these families has unique structural features which may prove in-teresting in future applications developments. Importantly, it is shown that wheth-er the chain length is odd or even plays a role in structural type although it is not necessarily a requirement for a given structural type; furthermore, chain length itself is not strictly determinative of structural type.
Dehydration in a cobalt phosphonate was followed via in situ single crystal X-ray diffraction. The compound goes through a two-stage dehydration mecha-nism in which the compound changes from a 1-D chain to a 2-D sheet. This pro-cess is reversible and shows unique switchable magnetic properties.
The high pressure studies of an alkyl chain built zinc metal phosphonate showed that the chains provide a spring-like cushion to stabilize the compression of the system allowing for large distortions in the metal coordination environment, without destruction of the material. This intriguing observation raises questions as to whether or not these types of materials may play a role as a new class of piezo-functional solid-state materials.
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Makal, Trevor Arnold. "Pendant Functional Groups in Metal-Organic Frameworks - Effects on Crystal Structure, Stability, and Gas Sorption Properties." Thesis, 2013. http://hdl.handle.net/1969.1/149331.
Повний текст джерелаАнотація:
The primary goal of this research concerns the synthesis and characterization of metal-organic frameworks (MOFs) grafted with pendant alkyl substituents to enhance stability and gas sorption properties for use in clean-energy related technologies. Initially, the focus of this work was on the synthesis and comparison of two isostructural MOFs built upon octahedral secondary building blocks; one with no alkyl substituents, and its dimethyl-substituted counterpart. The dimethyl-substituents are observed to enhance the stability of the framework, resulting in high Langmuir surface area (4859 m2 g-1) and hydrogen uptake capacity at 77 K and 1 bar (2.6 wt%).
In the second section, the length of pendant alkoxy substituents in semi-flexible MOFs was evaluated through the synthesis and characterization of two isostructural MOFs, one with dimethoxy (PCN-38) and one with diethoxy pendant groups (PCN-39). While PCN-38 exhibited moderate surface area and hydrogen uptake capacities, PCN-39 underwent structural change upon activation leading to a redistribution of pore sizes and selective adsorption of hydrogen over larger gases. This structural transformation is believed to originate from optimal space filling of the pendant groups.
In the third section, a series of NbO-type MOFs were synthesized with dimethoxy, diethoxy, dipropoxy, and dihexyloxy substituents and the relationship between chain length and framework stability identified. Increasing chain length was observed to increase moisture stability of the MOFs, resulting in a superhydrophobic material in the case of the dihexyloxy derivative. Thermal stability, however, decreased with increasing chain length, as evidenced from in situ synchrotron powder X-ray diffraction measurements (PXRD). This is in contrast to data obtained from thermogravimetric analysis and shows that the standard use of thermogravimetric analysis, which measures combustion temperatures, may not always provide an accurate description of the thermal stability of MOFs. The role of pendant groups in gas adsorption processes was evaluated through identification of side chains and guest species in the pores of MOFs through in situ synchrotron PXRD measurements.
In summary, three separate isostructural series of MOFs with various pendant groups have been discussed in this dissertation, with the roles of those pendant groups toward crystal structure, stability, and gas sorption properties analyzed.
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Alezi, Dalal. "Reticular Chemistry and Metal-Organic Frameworks: Design and Synthesis of Functional Materials for Clean Energy Applications." Diss., 2017. http://hdl.handle.net/10754/625043.
Повний текст джерелаАнотація:
Gaining control over the assembly of crystalline solid-state materials has been significantly advanced through the field of reticular chemistry and metal organic frameworks (MOFs). MOFs have emerged as a unique modular class of porous materials amenable to a rational design with targeted properties for given applications. Several design approaches have been deployed to construct targeted functional MOFs, where desired structural and geometrical attributes are incorporated in preselected building units prior to the assembly process.
This dissertation illustrates the merit of the molecular building block approach (MBB) for the rational construction and discovery of stable and highly porous MOFs, and their exploration as potential gas storage medium for sustainable and clean energy applications. Specifically, emphasis was placed on gaining insights into the structure-property relationships that impact the methane (CH4) storage in MOFs and its subsequent delivery. The foreseen gained understanding is essential for the design of new adsorbent materials or adjusting existing MOF platforms to encompass the desired features that subsequently afford meeting the challenging targets for methane storage in mobile and stationary applications.In this context, we report the successful use of the MBB approach for the design and deliberate construction of a series of novel isoreticular, highly porous and stable, aluminum based MOFs with the square-octahedral (soc) underlying net topology. From this platform, Al-soc-MOF-1, with more than 6000 m2/g apparent Langmuir specific surface area, exhibits outstanding gravimetric CH4 uptake (total and working capacities). It is shown experimentally, for the first time, that the Al-soc-MOF platform can address the U.S. Department of Energy (DOE) challenging gravimetric and volumetric targets for the CH4 working capacity for on-board CH4 storage. Furthermore, Al-soc-MOF-1 exhibits the highest total gravimetric and volumetric uptake for carbon dioxide and the utmost total and deliverable uptake for oxygen at relatively high pressures among all microporous MOFs.
Additionally, the research studies presented in this dissertation highlight the latest discoveries on our continuous quest for highly-connected nets. Specifically, we report the discovery of two fascinating and highly-connected minimal edge-transitive nets in MOF chemistry, namely pek and aea topologies, via a systematic exploration of rare earth metal salts in combination with relatively less symmetrical 3-connected tricarboxylate ligands. Adsorption studies revealed that pek-MOF-1 offers excellent volumetric CO2 and CH4 uptakes at high pressures.
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Chang, Yu-Tzu, and 張育慈. "Syntheses, Characterizations and Functional Properties of Nanoporous Frameworks of Organic-inorganic Hybrid Metal Phosphates and Phosphites." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/4ykmdd.
Повний текст джерела
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Tarzia, Andrew. "Computational Screening and Analysis of Functional Porous Materials." Thesis, 2019. http://hdl.handle.net/2440/120096.
Повний текст джерелаАнотація:
Functional porous materials are a class of materials that have found use in many industrial applications. In particular, extended framework materials, such as metal–organic frameworks (MOFs) and porous aromatic frameworks (PAFs), which are the subject of this thesis, show significant promise for applications including gas storage and separations, catalysis, drug delivery, microelectronics and sensing. This broad scope of applications stems from the immense chemical diversity afforded by their modular bottom-up synthesis and design. Additionally, the rational choice of building blocks allows for the precise control of the properties of the pore networks of crystalline extended porous materials. However, the process of finding optimal porous materials for emerging applications is slow due to arduous trial-and-error experimental approaches. The application of computational methods to analyze porous materials allows for the development of design principles, which can guide experimental endeavors. Furthermore, high-throughput screening can be used to expand on experimental findings by efficiently exploring chemical space for the best candidates for a given application. This thesis reports several studies in which novel computational protocols are developed and applied to more rapidly screen porous functional materials for applications. A coarse-grained molecular dynamics model was developed to investigate the formation mechanism of PAFs and the role of structural and dynamics factors in determining their highly porous, amorphous networks. PAF formation, which is kinetically controlled, was found to robustly lead to a high degree of defects and porosity, and that relatively weak dispersion interactions are responsible for inducing porosity-reducing interpenetration. The simulations suggest that bulky reaction intermediates or building blocks with diminished dispersion interactions can be used to eliminate interpenetration and increase material porosity. Highly-ordered MOF thin films with macroscale in-plane and out-of-plane alignment have many potential applications, but only a handful of examples have been reported to date. Therefore, a high-throughput screening process was developed to suggest new MOFs that are likely to undergo aligned growth. The screening process was parameterized from a set of experimental observations of the aligned growth of copperbased MOFs from copper(II) hydroxide (Cu(OH)2) and allows for the screening of thousands of MOF structures in a few days. Importantly, the number of known MOFs that are likely to grow aligned from Cu(OH)2 was expanded and some design principles were uncovered. In particular, it was found that the substrate imparts a directing effect on the MOFs able to grow aligned, but does not limit the possible pore network properties of aligned MOFs. The biomimetic mineralization of MOFs around biomacromolecules was investigated in two joint experimental and computational studies. Biomimetic mineralization is a general and facile method for encapsulating biological entities to, for example, enhance their stability in harsh conditions. Systematic experimental studies of the encapsulation of proteins and carbohydrates by zeolitic imidazolate framework-8 (ZIF- 8) found that the electrostatic properties of the biomacromolecule govern biomimetic mineralization and showed that chemical functionalization can be used to control this process. Computational modelling verified the role of the negative charge on biomacromolecules in inducing ZIF growth as a result of enhancement of the surrounding zinc ion concentration. Furthermore, calculations of the surface electrostatic potential and pI of a protein were shown to accurately and efficiently predict whether a biomacromolecule seeds MOF growth. Finally, a high-throughput screening process was developed to explore enzymatic reaction space to discover candidate reactions for MOF-encapsulated enzymes. This screening process uses the molecular size of the components of a reaction to predict whether the reaction can occur inside MOFs. The number of possible enzymatic reactions that have been carried out inside ZIF-8 is very small, and many of those reactions were found to have components that are likely too big to diffuse through ZIF-8. Therefore, the screening process was applied to suggest reactions that can investigate the relationship between the size of reaction components and enzymatic activity inside ZIF-8. In this process, a reaction of significant commercial value was identified that should occur in a MOF-encapsulated enzyme.Thesis (Ph.D.) -- University of Adelaide, School of Physical Sciences, 2019
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Lee, Li-Wei, and 李立偉. "Self-Assembly, Structures, Gas Adsorption and Applications of Porous Metal–Organic Frameworks Constructed from Multi-pyridyl Ligands." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/5tfebp.
Повний текст джерелаАнотація:
博士國立中央大學
材料科學與工程研究所
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In this thesis, a series of porous metal–organic framework (MOFs) were synthesized by reacting rigid multi-pyridyl ligands, various dicarboxylate ligands and d10 metal ions (Zn2+ and Cd2+) under mild reaction conditions. The structures of these compounds range from one dimensional single-walled nanotubes, and two dimensional layers to three dimensional networks. The structure of the compounds {[Zn2(azpy)(aip)2]·2DMF}n (1), {[Zn2(dipytz)(aip)2]·DMF·MeOH}n (2), and {[Zn2(tpim)(aip)2]·2.5DMF·2H2O}n (3) assume a two-dimensional pillared-bilayer framework with 1D channels created inside the bilayers. Compounds {[Zn2(tpim)2(D-cam)2]·10H2O}n (4) and {[Zn2(tpim)2(L-cam)2]·10H2O}n (5) are composed of homochrial two-dimensional layers with a rectangle-like (4,4) topology. Compound {[Cd2(tpim)4(SO4)(H2O)2]·(SO4)·21H2O}n (6) shows a two-dimensional layer structure with a brick-wall-type (6,3) topology. Compound {[Zn(4-abpt)0.5(3,4-pydc)]·DMAc·1.5MeOH·0.5H2O}n (7) features a three-dimensional pillared-layer framework with a (3,4)-connected net. Compound {[Zn(4-pimp)(3,4-pydc)]·2DMAc}n (8) adopts a homochiral two-dimensional layered structure and {[Zn2(tpim)(3,4-pydc)2]·4DMF·4H2O}n (9) displays a homochiral three-dimensional pillared-layer network. Compound [Zn(tpim)(cis-1,4-chdc)]·3H2O (10) displays an independent 1D single-walled metal–organic nanotube and [Zn2(tpim)2(trans-1,4-chdc)2]·6H2O (11) shows a two-dimensional layered structure. All of the compounds are porous materials with different pore volumes and channel shapes. The pillared-bilayer frameworks of 1–3 have different pore volumes and channel shapes depending on the length and shape of the pillar ligands as well being feasible to tune the structural flexibility (1 and 2) or rigidity (3) through solvent-exchange processes. The resoluting MOFs exhibit a higher selective adsorption of CO2 over H2 and N2. It is noteworthy that the enantiopure compounds 4 and 5 showed an uncommon gate-opening effect on CO2 sorption and displayed a wide hysteresis loop upon desorption under ambient conditions. Compound 6 consists of a 2D layer structure with two types of sulfate anions and exhibits anion exchange capability with SCN− or N3− anions. Interestingly, the anion-exchanged products of 6 with SCN− or N3− are very different. Compound 7 adopted a three-dimensional porous pillared-layer framework with 1D honeycomb channels. Remarkably, the tetrahedral coordination environment of ZnII ions in 7 could be changed by the presence of other transition metal ions in a DMAc solution. Furthermore, compound 7 also displayed significant non-linear optical behavior. Compounds 8 and 9 crystallize in the homochiral orthorhombic space group P212121. Compound 8 adopted a 2D layer structure. Compound 9 showed a 3D pillared-layer framework with the rectangular-shape one-dimensional channels and revealed significant reversible the thermochromic behavior. Compounds 10 and 11 were constructed from the conformationally flexible 1,4-H2chdc (cis- or trans-) and tpim ligands under hydrothermal conditions and displayed different gas adsorption behaviors.
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Alamer, Badriah. "Design, Synthesis and Characterization of Functional Metal-Organic Framework Materials." Thesis, 2015. http://hdl.handle.net/10754/565110.
Повний текст джерелаАнотація:
Over the past few decades, vast majority of industrial and academic research throughout the world has witnessed the emergence of materials that can serve as ideal candidates for potential utility in desired applications, and these materials are known as Metal Organic Framework (MOFs). This exceptional new family of porous materials is fabricated by linkage of metal ions or clusters and organic linkers via strong bonds. MOFs have been awarded with remarkable interest and widely studied due to their inherent structural methodology (e.g. use of various metals, expanded library of organic building blocks with different geometry and functionality particularly frameworks designed from carboxylate organic linkers) and unquestionably unique structural and chemical features for many practical applications. (i.e. gas storage/separation, catalysis, drug delivery etc). Simply, metal organic frameworks epitomize the beauty of porous chemical structures. From a design perspective, the introduction of the Molecular Building Block (MBB) approach is actively being pursued pathway by researchers toward the construction of MOFs by employing inorganic building blocks and organic linkers and taking advantage of not only their multiple coordination modes and geometries but also the way in which they are reticulated to generate final framework. In this thesis, research studies will be directed toward (i) the investigation of the relationship between experimental parameters and synthesis of well-known fcu –MOF, (ii) rational design and synthesis of new rare earth (RE) based MOFs, (ii) isoreticular materials based on particular MBB
([M3O(RCO2)6]), M= p-and d-block metals, and (iv) zeolite- like metal organic framework assembled from single-metal ion based MBB ([MN2(CO2)4]) via 2-, 3-,and 4-connected organic linkers. Consequently, the porosity, chemical and thermal stability, and gas sorption properties will be evaluated and detailed.
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Bhat, Soumya S. "First-Principles Studies of Point Defects and Phase Transformations in Materials." Thesis, 2014. http://etd.iisc.ac.in/handle/2005/3022.
Повний текст джерелаАнотація:
The functional and mechanical properties of a material are often determined by the defects in them. A thorough understanding of the relationship between the defects and the properties allows for tailoring a material’s properties into the desired combinations. Amongst the different classes of defects, experimental identification of point defects is typically difficult and indirect, usually requiring an ingenious combination of different techniques. In this context, first-principles calculations, complemented with experiments, offer insights into the formation of defects and their role in properties. This was demonstrated in this thesis through investigations on the effect of calcium vacancies on structure, vibrational and elastic properties hydroxyapatite (HAp), and oxygen vacancies on elastic properties of zinc oxide (ZnO) using first-principles calculations based on density functional theory (DFT). Our results confirm a considerable reduction in the elastic constants of HAp—the inorganic constituent of bone—due to Ca-deficiency, which was experimentally reported earlier. Elastic anisotropic behavior of stoichiometric and Ca-deficient HAp is analyzed, which will be useful in understanding the effects of crystal orientation in designing synthetic bone. Local structural stability of HAp and Ca-deficient HAp structures is assessed with full phonon dispersion studies and the specific signatures in the computed vibrational spectra for Ca deficiency in HAp can be utilized in experimental characterization of different types of defected HAp. In ZnO, formation energies of oxygen vacancies in different types of oxygen deficient structures are analyzed to ascertain their stability. Our results show considerable degradation of some of the elastic moduli due to the presence of such vacancies. Further, the charge state of the defect structure is found to influence the shear elastic constants. Evaluation of elastic anisotropy of stoichiometric and oxygen deficient ZnO indicates the significant anisotropy in elastic properties and stiff c-axis orientation.
The second part of the thesis deals with developing some understanding of the pressure-induced phase transformations (PIPT) in an inorganic material, titanium nitride (TiN), and in a metal-organic framework (MOF), erbium formate crystal. PIPT, which is a common phenomenon in many materials, is of great interest in materials science as the properties of the transformation product can diverge significantly from those of the parent phase. Hence, it is important to understand the pressure induced changes so to improve the component reliability and to enhance service life of materials used in high pressure applications. TiN undergoes PIPT from NaCl to CsCl structure. On the basis of our DFT calculations, we propose a new transformation path, which shows that the stress required for this transformation is substantially lower when it is deviatoric in nature than that under hydrostatic pressure. Local stability of the structure is assessed with phonon dispersion determined at different pressures, and we find that CsCl structure of TiN is expected to distort after the transformation. Further, we provide a quantitative comparison of electronic structure of TiN in NaCl structure with that of high pressure phase with implication to electrical conduction properties. Next, we investigate the PIPT associated with bond rearrangement in erbium formate framework. Phase transition pressure is estimated and the corresponding changes in bonding characteristics are analyzed. Estimated lattice constants for both the phases agree well with the earlier experimental results. While the transformation pressure of the framework is overestimated with respect to experiment, our calculations confirm PIPT, and thus provide a theoretical evidence for the experimental finding.
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Bhat, Soumya S. "First-Principles Studies of Point Defects and Phase Transformations in Materials." Thesis, 2014. http://hdl.handle.net/2005/3022.
Повний текст джерелаАнотація:
The functional and mechanical properties of a material are often determined by the defects in them. A thorough understanding of the relationship between the defects and the properties allows for tailoring a material’s properties into the desired combinations. Amongst the different classes of defects, experimental identification of point defects is typically difficult and indirect, usually requiring an ingenious combination of different techniques. In this context, first-principles calculations, complemented with experiments, offer insights into the formation of defects and their role in properties. This was demonstrated in this thesis through investigations on the effect of calcium vacancies on structure, vibrational and elastic properties hydroxyapatite (HAp), and oxygen vacancies on elastic properties of zinc oxide (ZnO) using first-principles calculations based on density functional theory (DFT). Our results confirm a considerable reduction in the elastic constants of HAp—the inorganic constituent of bone—due to Ca-deficiency, which was experimentally reported earlier. Elastic anisotropic behavior of stoichiometric and Ca-deficient HAp is analyzed, which will be useful in understanding the effects of crystal orientation in designing synthetic bone. Local structural stability of HAp and Ca-deficient HAp structures is assessed with full phonon dispersion studies and the specific signatures in the computed vibrational spectra for Ca deficiency in HAp can be utilized in experimental characterization of different types of defected HAp. In ZnO, formation energies of oxygen vacancies in different types of oxygen deficient structures are analyzed to ascertain their stability. Our results show considerable degradation of some of the elastic moduli due to the presence of such vacancies. Further, the charge state of the defect structure is found to influence the shear elastic constants. Evaluation of elastic anisotropy of stoichiometric and oxygen deficient ZnO indicates the significant anisotropy in elastic properties and stiff c-axis orientation.
The second part of the thesis deals with developing some understanding of the pressure-induced phase transformations (PIPT) in an inorganic material, titanium nitride (TiN), and in a metal-organic framework (MOF), erbium formate crystal. PIPT, which is a common phenomenon in many materials, is of great interest in materials science as the properties of the transformation product can diverge significantly from those of the parent phase. Hence, it is important to understand the pressure induced changes so to improve the component reliability and to enhance service life of materials used in high pressure applications. TiN undergoes PIPT from NaCl to CsCl structure. On the basis of our DFT calculations, we propose a new transformation path, which shows that the stress required for this transformation is substantially lower when it is deviatoric in nature than that under hydrostatic pressure. Local stability of the structure is assessed with phonon dispersion determined at different pressures, and we find that CsCl structure of TiN is expected to distort after the transformation. Further, we provide a quantitative comparison of electronic structure of TiN in NaCl structure with that of high pressure phase with implication to electrical conduction properties. Next, we investigate the PIPT associated with bond rearrangement in erbium formate framework. Phase transition pressure is estimated and the corresponding changes in bonding characteristics are analyzed. Estimated lattice constants for both the phases agree well with the earlier experimental results. While the transformation pressure of the framework is overestimated with respect to experiment, our calculations confirm PIPT, and thus provide a theoretical evidence for the experimental finding.