Dissertations / Theses on the topic 'Crystalline Covalent Organic Frameworks'
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Baldwin, Luke Adam. "Synthesis of Dehydrobenzoannulene-Based Covalent Organic Frameworks." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1491561788473597.
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Dogru, Mirjam. "Functionalization of covalent organic frameworks." Diss., Ludwig-Maximilians-Universität München, 2012. http://nbn-resolving.de/urn:nbn:de:bvb:19-140963.
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Covalent Organic Frameworks (COFs) are a novel class of highly stable, purely organic crystalline frameworks made of molecular building blocks. For example, the condensation of boronic acids with appropriate polyols in principle allows the design of precisely controllable structures since their chemical and physical properties can be easily tuned through the selection of the building blocks. The young research field of COFs has attracted scientists due to their extraordinary and versatile properties, however, strategies to control the topology and the properties of the backbone as well as the inner surface are still not well established. With support of Prof. Knochel and his group, who contributed numerous new organic COF linkers, this thesis aims to extend the functionalization strategies for the design of Covalent Organic Frameworks. Investigation of the structural modification and the associated change in physical and chemical properties should lead to progress regarding the applicability of these materials.
Employing the concept of reticular chemistry in combination with High Throughput Synthesis Techniques, the formation of a very large Covalent Organic Framework BTP-COF with 4 nm open pores was successfully carried out. The solvothermal co-condensation of 1,3,5-benzenetris(4-phenylboronic acid) (BTPA) and 2,3,6,7-tetrahydroxy-9,10-dimethyl-anthracene (THDMA) was carried out using microwave irradiation instead of conventional synthesis in an oven, thus synthesis time of BTP-COF was reduced from initially 72 h to 5 min. Extending the open pore diameter of a crystalline material to 4 nm, in combination with the resulting high accessible surface area of 2000 m2/g offers great potential to exploit organic reactions in the pores and enables the incorporation of large functional guests, such as polymers or dyes. Bearing these results in mind the scope of functionalization possibilities was expanded from the geometric extension to the chemical modification of the inner surface of COFs. Decorating the organic building blocks with small functional active groups, such as methyl-, -methoxy- and hydroxy- allowed for the successful synthesis of several organic frameworks. Chemical and physical properties of the backbone and the inner surface can be precisely tailored by chemical modification of the building blocks. In order to investigate post-synthetic modification strategies, the methyl- and hydroxy-groups were used as reaction anchor points to covalently attach molecules after framework formation. The co-condensation of benzene-1,3,5-triyltriboronic acid (BTBA) and the 9,10-dimethyl-anthracene-2,3,6,7-tetraol (DMAT) succeeded in the formation of AT-COF-Me. In a radical bromination reaction the methyl groups of an anthracene linker were successfully brominated giving AT-COF-Br without degrading the crystalline framework of AT-COF-Me. The formation of the resulting benzylic bromine was monitored with IR spectroscopy and solid state NMR, respectively. Elemental analysis results correspond to the bromination of half the -CH3 groups. Reaction of (2',5'-dihydroxy-[1,1':4',1''-terphenyl]-4,4''-diyl)diboronic acid (HTDBA) and 2,3,6,7,10,11-hexahydroxytri-phenylene (HHTP) The terphenyl-based hydroxyl substituted T-COF-OH, formed by (2',5'-dihydroxy-[1,1':4',1''-terphenyl]-4,4''-diyl)diboronic acid (HTDBA) and 2,3,6,7,10,11-hexahydroxytri-phenylene (HHTP), was tested in several nucleophilic substitution reactions. Esterification of the –OH group was achieved with either acetylchloride or in a Steglich type reaction with 4-pentynoic acid. X-ray diffraction analysis after the post-synthetic modification shows that the crystallinity of the framework was preserved. This indicates that T-COF-OH is compatible with the reaction conditions. The detection of the newly formed ester moieties in IR and in solid state NMR spectra proves the successful post-synthetic esterification of the –OH groups. Another approach to tailor functionality in COFs is to assemble monomers with distinct properties in COF synthesis. Modification of the backbone of the framework was realized with two heterocyclic building blocks. Benzothiadiazole (BTD) and thienothiophene (TT) monomers are known as building blocks of semiconducting polymers. These molecules were equipped with boronic acid or boronate ester moieties in para position. The linkers were then used in co-condensation reactions with HHTP. The synthesis of BTD-COF was carried out in a two step microwave synthesis procedure: first the pinacolboronate 4,7-Bis(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)benzo[c][1,2,5]thiadiazole (BTDA) was cleaved with HCl, in a second step addition of HHTP resulted in the crystalline product in only 60 min. TT-COF was synthesized in a conventional co-condensation reaction of thieno[3,2-b]thiophene-2,5-diyldiboronic acid (TTBA) with HHTP; the black TT-COF showed aborbance over the whole spectrum of the visible light. Upon irradiation with light the system showed significant photoconductivity. The 3 nm pores of the hole-transporting TT-COF offer enough space to incorporate large fullerene-based electron-transporting materials such as PCBM. This inclusion leads to a significant quenching of the luminescence of TT-COF, indicating light-induced charge transfer at the interface of these two materials.
The oriented growth of thin films of porous COF-10, a product of the condensation of 4,4’-biphenyldiboronic acid(BPBA) and HHTP, and TT-COF on self-assembled monomer (SAM)-functionalized gold surfaces is shown. Films grown on boronic acid terminated SAMs result in a parallel orientation of the pores along the substrate. Scanning electron microscopy was used to investigate the morphology of the films. Homogenous films with thicknesses of around 150 nm and a total coverage of the substrates were obtained.
In summary, several functionalization strategies are shown to control or tune the topology and properties of Covalent Organic Frameworks. Tuning the topology and functionality to large open pore systems or intrinsic semiconductivity allows incorporation of large functional molecules and study the host-guest interactions. The post-synthetic modification of COFs offers a synthetic pathway to integrate organic functionalities, which cannot be synthesized directly by co-condensation. These strategies provide the means necessary for a precise control of the pore environment and design a porous material for specific applications. A facile and rapid method to produce thin oriented COF films will pave the way for this material to fabricate technological devices, such as photovoltaic devices, sensors of OFETs.
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Spasic, Marko. "Redox-active covalent organic frameworks." Thesis, Uppsala universitet, Institutionen för kemi - BMC, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-449962.
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CARNEIRO, LEONARDO SIMÕES DE ABREU. "CARBAZOLE-BASED COVALENT ORGANIC FRAMEWORKS: CONCEPTION, SYNTHESIS AND CHARACTERIZATION." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2016. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=28356@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
Materiais bidimensionais apresentam possibilidades de funcionalização que os tornam versáteis para diversas aplicações, tais como em dispositivos eletrônicos. A presença de poros nesses materiais pode trazer novas funções, como adsorção de gases, liberação controlada de fármacos e catálise. Os covalent organic frameworks (COFs) são uma nova classe de materiais orgânicos porosos cristalinos que têm recebido destaque em química reticular. O objetivo dessa dissertação é apresentar a síntese e caracterização de quatro novos COFs baseados em carbazóis, que constitui uma classe de compostos utilizada na obtenção de polímeros condutores. O bloco de montagem principal utilizado foi o 3,6-diamino-9H-carbazol e as fontes de aldeído foram triformilfloroglucinol, triformilfenol, 1,3,5-tri(4-formilfenil)benzeno e triformilbenzeno para a síntese do RIO2, RIO3, RIO5 e RIO6, respectivamente. RIO2 e RIO3 apresentaram-se sob a forma ceto enamina e imina, respectivamente, além de pouca cristalinidade e baixa área específica. Através de cálculos baseados na Teoria do Funcional da Densidade (DFT), foi verificado que esses COFs apresentam suas folhas deslocadas e rotacionadas devido às interações eletrostáticas e para minimizar os momentos de dipolo das ligações N-H dos carbazóis. RIO5 e RIO6 também se apresentaram pouco cristalinos e com áreas específicas baixas. Apesar desses resultados, esses materiais ainda podem ser aplicados em eletrônica orgânica por apresentarem estrutura química compatível com tal aplicação.
Two-dimensional materials have functionalization possibilities that make them versatile for various applications such as in electronic devices. The presence of pores in these materials can give new features to them, such as gas adsorption, drug delivery and catalysis. The covalent organic frameworks (COFs) are a new class of crystalline porous organic materials that have been prominent in reticular chemistry. The purpose of this work is to present the synthesis and characterization of four new COFs based on carbazoles, which are a class of compounds used to obtain conductive polymers. The main building block used was 3,6-diamine-9H-carbazole with the aldehyde sources were triformylphloroglucinol, triformylphenol, 1,3,5-tri(4 formylphenyl)benzene and triformylbenzene to obtain RIO2, RIO3, RIO5 and RIO6, respectively. RIO2 and RIO3 are in keto-enamine and imine form, respectively, as well as have low crystallinity and low specific area. Calculus based on Density Functional Theory (DFT) found that these COFs present their sheets displaced and rotated due to electrostatic interactions and to minimize the dipole moments of the N-H bonds of carbazoles. In an attempt to avoid the absence of pores, RIO5 and RIO6 materials were synthesized, however these COFs also performed poorly crystalline and with low specific areas. Despite these results, these materials can also be applied in organic electronics by presenting chemical structure compatible with such application.
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Crowe, Jonathan William. "Design and Synthesis of Dehydrobenzoannulene Based Covalent Organic Frameworks." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1492098595103764.
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Dogru, Mirjam [Verfasser], and Thomas [Akademischer Betreuer] Bein. "Functionalization of covalent organic frameworks / Mirjam Dogru. Betreuer: Thomas Bein." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2012. http://d-nb.info/1020790482/34.
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Dienstmaier, Jürgen. "From supramolecular self-assembly to two-dimensional covalent organic frameworks." Diss., Ludwig-Maximilians-Universität München, 2013. http://nbn-resolving.de/urn:nbn:de:bvb:19-156623.
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The two main subjects of this thesis are the realization of supramolecular self-assembled monolayers at surfaces and the formation of surface-supported two-dimensional covalent organic frameworks. Both topics, albeit different, yield long-range ordered open-pore networks with quite different stabilities, depending on the strength and type of bonds holding them together. The surface of choice is mainly graphite, which is considered an inert substrate. Graphite yields pristine clean, very large and flat surfaces when cleaved, facilitating the observation in real space of the molecular networks adsorbed on these surfaces by means of the Scanning Tunneling Microscope (STM). STM is the main experimental technique used here. It was used to image mostly at the liquid-solid interface under ambient conditions.
Using a large tricarboxylic acid adsorbate, long-range order supramolecular self-assembled monolayers were obtained. These monolayers are formed via a delicate interaction balance between adsorbates, substrate, and solvent molecules. Weak van der Waal forces mediate the adsorbate-substrate interaction; hydrogen bonds, the adsorbate-adsorbate interaction. Also, depending on the solvent used and the concentration of adsorbates dissolved in it, different polymorphs are found on the substrate. To understand the nucleation and growth mechanism that give rise to the different self-assembled monolayers, thermodynamical considerations are used. Enthalpic and entropic contributions are evaluated for several of the polymorphs found, explaining their occurance on the basis of the Gibbs free energy per unit area. However, even if this work sheds some light on supramolecular self-assembly, adding also that much research has been done in this field, it is still very difficult to know a priori how adsorbates will behave on a substrate. Thus predictions of which patterns will ultimately arise are hampered.
To realize structures that are more stable than those formed via supramolecular self-assembly, several strategies have been proposed. Covalent bond formation is one of them, yielding strong and lightweight structures by using organic molecules composed primarily of light elements. The strength of covalent bonds ranges from strong to very strong, when compared to van der Waals and hydrogen bonds. This characteristic makes correction of possible structural errors difficult to almost impossible. However, when molecules with suitable functional groups are allowed to react under reversible conditions, error correction of covalent bonds becomes feasible, yielding regular structures with the energetically most favorable configurations. In this thesis, this is exemplified with the small 1,4-benzenediboronic acid molecules, yielding monolayers composed of very regular, long-range ordered covalent organic frameworks on graphite. Thermal stability is probed by exposing the structures to relatively high temperatures for prolonged times under atmospheric conditions. Further experiments with larger para-diboronic acids, under similar reversible conditions, yield the expected isotopological regular frameworks with larger unit cell parameters. This demonstrates the proof of principle for the formation of two-dimensional covalent organic frameworks.
These two main topics, supramolecular self-assembly and covalent bond formation on surfaces, constitute the basis of this thesis. It is organized as follows: A first part deals with the theoretical background of the main analytical instruments used in this work. Then, the thermodynamics of supramolecular self-assembly is presented, along with the studies of the different polymorphs found using a large tricarboxylic acid as building block. The final part deals with the formation of two-dimensional, long-range ordered covalent organic frameworks, made from organic molecules composed only of light elements. This work show that these last mentioned networks exhibit higher thermal stabilities when compared to self-assembled monolayers held together mainly by strong hydrogen bonds. The viability of larger heteromeric isotopological networks is also explored.
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Beirl, Toni Marie. "Synthesis and Characterization of Novel Imine-Linked Covalent Organic Frameworks." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1437559176.
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Hunt, Joseph Ray. "Synthesis, characterization, and gas adsorption properties of covalent organic frameworks." Diss., Restricted to subscribing institutions, 2009. http://proquest.umi.com/pqdweb?did=1779835631&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
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Turangan, Nikka Maria Joezar. "Synthesis and characterisation of covalent organic frameworks as thin films." Thesis, Queensland University of Technology, 2019. https://eprints.qut.edu.au/129108/1/Nikka_Turangan_Thesis.pdf.
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This research tackles the challenge of synthesising a highly porous material, known as a covalent organic framework, as a self-supporting membrane, with potential applications in gas and chemical filtration and storage. Micrometer-thick freestanding membranes were successfully synthesised in this project through two different techniques, which allowed selection of the chemical, physical and mechanical properties of the membrane.
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Rager, Sabrina [Verfasser], and Thomas [Akademischer Betreuer] Bein. "Tailoring the features of covalent organic frameworks / Sabrina Rager ; Betreuer: Thomas Bein." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2019. http://d-nb.info/1214593186/34.
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Greenwood, John. "Investigations into surface-confined covalent organic frameworks : towards developing novel enantioselective heterogeneous catalysts." Thesis, University of St Andrews, 2013. http://hdl.handle.net/10023/4293.
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There is an increasing necessity for the pharmaceutical industry to develop enantiomerically pure drugs. Up till now, production of enantiomerically pure molecules has been provided by harvesting them from plants or utilising homogeneous catalysis and biocatalysis. None of these methods are efficient means of production, and attention is now being directed towards heterogeneous enantioselective catalysis as the preferred technique. This is on account of the high product yield and ease of separation of catalyst from the reaction mixture. Over the past few decades, a great deal of research has been conducted into investigating the Ni catalysed hydrogenation of β-ketoesters and Pt catalysed hydrogenation of α-ketoesters. These are the most successful systems for enantioselective heterogeneous catalysis. However, they are unsuitable for industrial purposes due to the low thermal and mechanical stability of the modified surfaces. The main goal throughout this project has been the investigation of surface-confined covalent reactions. The motivation of this research is to develop enantioselective heterogeneous catalysis; covalent networks are believed to infer the necessary thermal and chemical stability required to chirally modify catalytic surfaces for docking interactions with reactant species. Covalent organic frameworks (COFs) on surfaces hold potential for a number of chemical applications, and not just in the field of heterogeneous catalysis; for example in areas such as molecular electronics and templating.
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Calik, Mona Julia [Verfasser], and Thomas [Akademischer Betreuer] Bein. "Development of functional covalent organic frameworks for optoelectronics / Mona Julia Calik ; Betreuer: Thomas Bein." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2016. http://d-nb.info/1138922811/34.
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Katekomol, Phisan [Verfasser], and Arne [Akademischer Betreuer] Thomas. "From Low-Temperature Carbons to Novel Covalent-Organic Frameworks / Phisan Katekomol. Betreuer: Arne Thomas." Berlin : Universitätsbibliothek der Technischen Universität Berlin, 2013. http://d-nb.info/1035802236/34.
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Lohse, Maria [Verfasser], and Thomas [Akademischer Betreuer] Bein. "Structural investigations and postsynthetic modifications in covalent organic frameworks / Maria Lohse ; Betreuer: Thomas Bein." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2017. http://d-nb.info/1180981723/34.
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Yazdi, Amirali. "Nanoengineering composites made of metal- and covalent- organic frameworks and inorganic nanoparticles using encapsulation techniques." Doctoral thesis, Universitat Autònoma de Barcelona, 2018. http://hdl.handle.net/10803/666772.
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La presente tesis doctoral se ha enfocado en el diseño y la síntesis de un nuevo tipo de materiales compuestos basados en metal-organic frameworks (MOFs) o covalent-organic frameworks (COFs) y nanopartículas inorgánicas y el uso de estos materiales compuestos para la catálisis heterogénea.
En el primer capítulo se introduce la familia de materiales compuestos dispersos en/sobre diferentes materiales haciendo especial énfasis en aquellos construidos con MOFs y COFs. En el capítulo 2 se presentan los objetivos generales de la tesis doctoral.
En el capítulo 3 se muestran los resultados del artículo “The influence of the MOF shell thickness on the catalytic performance of composites made of inorganic (hollow) nanoparticles encapsulated into MOFs” publicado en 2016 en la revista Catalysis Science & Technology. En el mismo se reporta la encapsulación de nanopartículas huecas de Platino y Paladio en el ZIF-8 formando así una serie de materiales compuestos en los cuales el espesor de la cáscara de ZIF-8 era modulada de manera sistemática.
En el capítulo 4, nanopartículas híbridas de tipo núcleo-coraza de Au/CeO2 dispersadas en microesféras de UiO-66 han sintetizados usando el método se atomización por secado con flujo continuo. Las propiedades catalíticas combinadas en una única partícula de los nanocristales de CeO2 y Au y la capacidad protectora de las microesféras porosas de UiO-66 hacen que estos materiales compuestos muestren resultados interesantes como catalizadores para la reacción de reducción de monóxido de Carbono. (T50 = 72 °C; T100 = 100 °C) con alta reusabilidad. Los resultados obtenidos han sido incluidos en el artículo. “Core-shell Au/CeO2 nanoparticles supported in UiO-66 beads exhibiting full CO conversion at 100 °C” publicado en la revista Journal of Materials Chemistry A en 2017.
Finalmente, en el capítulo 5, hemos demostrado que usando un método en dos pasos se pueden funcionalizar COFs confinando en ellos nanopartículas. La reacción directa entre el 1,3,5-tris(4-aminofenil)benceno y el 1,3,5-benzenetricarbaldehído en presencia de una variedad de nanopartículas metalícas o de óxidos de metal resulta en la encapsulación de estas nanopartículas en un polímero amorfo de iminas-enlazadas con forma de esfera. El Post-tratamiento de estas esferas con ácido acético en reflujo conduce a la obtención de esferas cristalinas de COFs basados en iminas. Además materiales compuestos basados en COF y nanopartículas de Au y Pd han demostrado ser catalíticamente activas. Estos resultados han sido publicados en el artículo “Confining Functional
Nanoparticles into Colloidal Imine-Based COF Spheres by a Sequential Encapsulation-Crystallization Method” publicado en la revista Chemistry a European Journal en 2017.The present PhD Thesis has been dedicated to the design and synthesis of a new type of composites of metal-organic frameworks (MOFs) or covalent-organic frameworks (COFs) with inorganic nanoparticles (iNPs) and the use of these composites for heterogeneous catalysis. In the first chapter, we introduce the family of composites made by supporting iNPs on/in different materials, focusing on those constructed with MOFs and COFs. Then, the general objectives of the Thesis are described in Chapter 2. Chapter 3 shows the results in “The influence of the MOF shell thickness on the catalytic performance of composites made of inorganic (hollow) nanoparticles encapsulated into MOFs”, Catalysis Science & Technology (2016). Herein, we report the encapsulation of hollow Pt or Pd nanoparticles (NPs) into ZIF-8, making a series of composites in which the ZIF-8 shell thickness has been systematically varied. By using these composites as catalysts for the reduction of 4-nitrophenol and Eosin Y, we show that the MOF shell thickness plays a key role in the catalytic performance of this class of composites. In Chapter 4, hybrid core-shell Au/CeO2 NPs dispersed in UiO-66 shaped into microspherical beads are created using the spray-drying continuous-flow method. The combined catalytic properties of nanocrystalline CeO2 and Au in a single particle and the support and protective function of porous UiO-66 beads make the resulting composites show good performances as catalysts for CO oxidation (T50 = 72 °C; T100 = 100 °C) and recyclability. The results are included in the manuscript entitled “Core-shell Au/CeO2 nanoparticles supported in UiO-66 beads exhibiting full CO conversion at 100 °C”, Journal of Materials Chemistry A (2017). Finally, in Chapter 5, we demonstrated a two-step method that enables imparting new functionalities to COFs by nanoparticle confinement. The direct reaction between 1,3,5-tris(4-aminophenyl)benzene and 1,3,5-benzenetricarbaldehyde in the presence of a variety of metallic/metal-oxide nanoparticles resulted in the embedding of the nanoparticles in amorphous and nonporous imine-linked polymer organic spheres. Post-treatment reactions of these polymers with acetic acid under reflux led to crystalline and porous imine-based COF- hybrid spheres. Interestingly, porous imine-based COF-hybrids with Au and Pd NPs were found to be catalytically active. These results have been reported in the publication entitled “Confining Functional Nanoparticles into Colloidal Imine-Based COF Spheres by a Sequential Encapsulation-Crystallization Method”. Chemistry a European Journal (2017).
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Dienstmaier, Jürgen [Verfasser], and Markus [Akademischer Betreuer] Lackinger. "From supramolecular self-assembly to two-dimensional covalent organic frameworks / Jürgen Dienstmaier. Betreuer: Markus Lackinger." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2013. http://d-nb.info/1034813374/34.
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Wang, Mingchao, Marco Ballabio, Mao Wang, Hung-Hsuan Lin, Bishnu P. Biswal, Xiaocang Han, Silvia Paasch, et al. "Unveiling Electronic Properties in Metal–Phthalocyanine-Based Pyrazine-Linked Conjugated Two-Dimensional Covalent Organic Frameworks." American Chemical Society, 2019. https://tud.qucosa.de/id/qucosa%3A72450.
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π-Conjugated two-dimensional covalent organic frameworks (2D COFs) are emerging as a novel class of electro-active materials for (opto-)electronic and chemiresistive sensing applications. However, understanding the intricate interplay between chemistry, structure and conductivity in π-conjugated 2D COFs remains elusive. Here, we report a detailed charac-terization for the electronic properties of two novel samples consisting of Zn- and Cu-phthalocyanine-based pyrazine-linked 2D COFs. These 2D COFs are synthesized by condensation of metal-phthalocyanine (M=Zn and Cu) and pyrene derivatives. The obtained polycrystalline-layered COFs are p-type semiconductors both with a band gap of ~1.2 eV. Mobilities up to ~5 cm²/Vs are resolved in the dc limit, which represent a lower threshold induced by charge carrier localization at crystalline grain boundaries. Hall Effect measurements (dc limit) and terahertz (THz) spectroscopy (ac limit) in combination with den-sity functional theory (DFT) calculations demonstrate that varying metal center from Cu to Zn in the phthalocyanine moiety has a negligible effect in the conductivity (~5×10⁻⁷ S/cm), charge carrier density (~10¹² cm⁻³), charge carrier scattering rate (~3×10¹³ s⁻¹), and effective mass (~2.3m₀) of majority carriers (holes). Notably, charge carrier transport is found to be aniso-tropic, with hole mobilities being practically null in-plane and finite out-of-plane for these 2D COFs.
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Schwartz, Heidi Annemarie [Verfasser]. "Metal-Organic Frameworks as Crystalline Porous Hosts for Photoactive Molecules / Heidi Annemarie Schwartz." München : Verlag Dr. Hut, 2018. http://d-nb.info/1168534356/34.
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Sick, Torben [Verfasser], and Thomas [Akademischer Betreuer] Bein. "Synthesis and characterization of nanoporous covalent organic frameworks for optoelectronic applications / Torben Sick ; Betreuer: Thomas Bein." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2018. http://d-nb.info/121549971X/34.
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Keller, Niklas [Verfasser], and Thomas [Akademischer Betreuer] Bein. "Design principles to enhance optoelectronic properties in oligothiophene-based covalent organic frameworks / Niklas Keller ; Betreuer: Thomas Bein." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2020. http://d-nb.info/1228270562/34.
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Basagni, Andrea. "Covalent stabilization of 2D self-assembled nanostructures on surfaces." Doctoral thesis, Università degli studi di Padova, 2016. http://hdl.handle.net/11577/3424495.
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The rise of graphene has attracted great interest in low-dimensional materials (0D, 1D and 2D). A joint effort among the different branches of science (chemistry, physics, materials science and related areas) is directed towards the production of new intriguing materials with tuneable graphene-like properties. Promising is the direct synthesis of organic nanostructures on metal surfaces under ultrahigh-vacuum conditions (UHV). Perfect tuning of the reaction conditions, high control of the surface symmetry and of its corrugation, a rich variety of substrate materials are only some of the advantage that UHV may offer. Although several reactions have been tested, it seems clear that to achieve ordered covalent monolayers more complex approaches are needed. In this thesis, the on-surface polymerization of covalent nanostructures has been studied for different coupling reactions, substrate materials and reaction conditions. Scanning tunneling microscopy and X-ray photoelectron spectroscopy are used for the characterization, allowing complementary analysis of molecular structures and chemical states. In particular, thermally activated reactions were used to gradually polymerize the 4,4”-dibromo-terphenyl precursor into poly-paraphenylene wires, through an Ullmann-like reaction scheme on Au(111), and then into graphene nanoribbons, after activation of the C-H bonds. A fine balance between the catalytic activity of the surface, molecular mobility and favourable molecular organization allowed us to get extended and ordered covalent structures. Taking advantage of this synthetic pathway, three different mono-dimensional polymers were obtained, namely poly-paraphenylene and two pyridinic derivatives, with gradually increased nitrogen content. Macroscopically anisotropic samples have been prepared by taking advantage of the vicinal surface templating effect. Using angle resolved photoemission spectroscopy, we reveal that the electronic structure of doped polymers is monotonically downshifted with respect to the metal Fermi level as the pyridine substitution is increased within the molecular scaffold.
Finally, the photochemical activation of different functional groups has been explored. These studies represents a step forward in the application of organic photochemistry to on-surface synthesis, which is currently limited to the use of diacetylene groups, and it opens up new opportunities for using several organic functional groups as photoactive centres for the synthesis of covalent organic frameworks.La scoperta del grafene ha suscitato grande interesse verso i materiali a bassa dimensionalità (0D, 1D e 2D) e uno sforzo congiunto tra i diversi rami della scienza è orientato verso la produzione di nuovi materiali con proprietà analoghe a quelle del grafene, ma controllabili. La sintesi su superficie in condizioni di ultra-alto vuoto (UHV) sembra essere promettente per la produzione di nanostrutture organiche. Infatti, in queste condizioni, è possibile avere un’ampia varietà di materiali, un perfetto controllo delle condizioni di reazione, della simmetria della superficie e della sua corrugazione. Questi sono solo alcuni dei vantaggi che l’UHV offre. Sebbene varie reazioni siano state testate negli ultimi anni, sembra chiaro che per realizzare monostrati polimerici ordinati siano necessiari approcci più complessi. In questo lavoro di Tesi, la sintesi di nanostrutture polimeriche su superficie è stata studiata per diverse reazioni, substrati e condizioni di reazione. La microscopia ad effetto tunnel e la spettroscopia di fotoemissione a raggi X sono state utilizzate per la caratterizzazione dei diversi sistemi permettendo un'analisi complementare delle strutture molecolari e dei loro stati chimici. In particolare, le reazioni attivate termicamente sono state utilizzate per polimerizzare gradualmente il 4,4"-dibromo-terfenile e ottenere, in un primo step di reazione, per mezzo della reazione di Ullmann su Au (111), il poli-parafenilene, ,e poi nanoribbons di grafene dopo l'attivazione del legami C-H. Un delicato equilibrio tra l'attività catalitica della superficie, la mobilità molecolare e l’organizzazione molecolare ha permesso di ottenere strutture ordinate estese. Inoltre, sfruttando questa metodica, sono stati ottenuti tre differenti polimeri 1D, caratterizzati da un crescente contenuto di azoto. Campioni macroscopicamente anisotropici sono stati preparati sfruttando l'effetto templante delle superfici vicinali e, grazie alla spettroscopia di fotoemizzione risolta in angolo, è stato rivelato che la struttura elettronica dei polimeri drogati è rigidamente spostata verso energie minori rispetto al livello di Fermi del metallo all'aumentare del contenuto di azoto. Infine, è stata esplorata l'attivazione fotochimica di diversi gruppi funzionali. Questi studi rappresentano un passo avanti verso l’applicazione della fotochimica alla sintesi su superficie, che attualmente sfrutta solo gruppi diacetilenici, e apre nuove opportunità per l'utilizzo di diversi gruppi funzionali organici come centri fotoattivi.
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Pyles, David Andrew. "Design and Application of Novel Benzobisoxazole and Benzobisthiazole Linked Porous Polymers." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu155428770646841.
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Stegbauer, Linus Martin [Verfasser], and Bettina [Akademischer Betreuer] Lotsch. "Two-dimensional covalent organic frameworks as platforms for renewable energy and environmental applications / Linus Martin Stegbauer ; Betreuer: Bettina Lotsch." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2016. http://d-nb.info/1184794065/34.
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Gottschling, Kerstin [Verfasser], and Bettina [Akademischer Betreuer] Lotsch. "Towards single-site heterogeneous catalysts for the hydrogen evolution reaction based on covalent organic frameworks / Kerstin Gottschling ; Betreuer: Bettina Lotsch." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2020. http://d-nb.info/1218466081/34.
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Motegi, Hirofumi. "Synthesis and Characterization of Crystalline Coordination Networks Constructed From Neutral Imidazole Containing Ligand and Rigid Aromatic Carboxylate." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/77201.
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The work is focused on the investigation of synthesis and structure of crystalline coordination networks by combining first a row transition metal ion with one anionic and one neutral bridging ligand. In the field of crystalline coordination networks, the goal is to synthesize porous 3D crystalline coordination networks with molecular sized cavities. The materials are characterized by XRD and TGA. It is important to understand the structural topologies to develop practical applications, such as gas storage, gas separation, and catalysis.
The bi- and tetra- dentate flexible imidazole ligands, 9,10-bis(imidazol-1-ylmethyl)anthracene (Chapter 2) and 1, 2, 4, 5-tetrakis(imidazol-1ylmethyl)benzene (Chapter 3), are synthesized and used as linkers to construct 1D, 2D, and 3D crystalline coordination networks with cobalt(II) or zinc(II) cations and H3BTC anions under solvothermal conditions.
Two 1D chain networks, [M(HBTC²⁻)(C₂₂H₁₈N₄)(H₂O)₂]•H₂O, are constructed from M(Zn(II) or Co(II)), H₃BTC, and 9,10-bis(imidazol-1-ylmethyl)anthracene (Compound 2.1 and 2.2). These two 1D zigzag chains are linked into infinite 2D sheets by inter-chain π•••π stacking and hydrogen bonding. ⁺
Two 2D and one 3D cobalt(II) coordination networks are constructed from the tetradentate imidazole ligand and H3BTC. Compound 3.1 has a 2D corrugated sheet structure that is linked by inter-layer π•••π stacking and hydrogen bonding. Compound 3.2 has a 2D sheet structure. These sheets are interconnected by hydrogen bonds at the free acid group of the HBTC²⁻ ligand. Compound 3.3 forms a two fold interpenetrated 3D network structure. Void spaces in the structure are filled with six water molecules.
Six 3D cobalt (II) coordination networks are constructed with bidentate rigid imidazole containing neutral ligands, 1,4-bis(imidazol-1-yl)benzene(L1), 1,4-bis(imidazol-1-yl)naphthalene(L2), and 9,10-bis(imidazol-1-yl)anthracene(L3), and H₂BDC or H₃BTC anion (Chapter 4). In 4.1-4.3, L1-L3 affects on degree of interpenetrations constructed with H₂BDC ligand. In 4.1 and 4.2 are interpenetrating 3D networks with no accessible void space. In 4.3, void spaces of 3D networks are filled with 2D sheets. Compounds 4.4-4.6 are prepared by different concentrations of starting materials and different solvents. In 4.4-4.6, L3 serves as a pillar building block to construct 3D networks by applying with H₃BTC ligand. The solvent exchange experiment for 4.4 is further discussed.Ph. D.
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Brunet, Gabriel. "Investigating the Single Crystal to Single Crystal Transformations of Highly Porous Metal-Organic Frameworks Through the Crystalline Sponge Method." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/34308.
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The development of a new technique capable of analyzing compounds crystallographically without first needing to crystallize them has been recently described. The present thesis aims to demonstrate the potential of such a technique, which utilizes crystalline sponges, in order to regularly order guest compounds in a porous media. The structural stability of the molecular sponges, which are highly porous metal-organic frameworks (MOFs), is first investigated, revealing that the Co-based MOF, 1, undergoes two remarkable transformations. This thesis also demonstrates how the technique can be employed to visualize the motion and occupancy of gaseous guests in a MOF. The Zn-based MOF, 4, was found to physisorb and chemisorb molecular iodine, leading to the formation of a variety of polyiodide species. The flexible nature of the host was determined to be an essential component in the exceptionally large iodine uptake capacity of the MOF. These results illustrate that the crystalline sponge method can be an effective strategy for directly visualizing guest molecules and obtaining vital information on the interactions formed between the host and guest.
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Bushell, Alexandra. "Mixed matrix membranes of a polymer of intrinsic microporosity with crystalline porous solids." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/mixed-matrix-membranes-of-a-polymer-of-intrinsic-microporosity-with-crystalline-porous-solids(6166d350-d969-49bc-8108-1c9afcaaa2f9).html.
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This work explores the fabrication and permeability testing of mixed matrix membranes (MMM) utilising a polymer of intrinsic microporosity (PIM-1) and various fillers. PIM-1 has been chosen for this work due to its high apparent surface area and high sorption of gases. PIM-1 also is a good candidate for gas sorption applications due to the film forming properties of the polymer. The fillers utilised in this work are Metal Organic Frameworks (MOFs) and organic cages, which have been chosen due to the gas sorption properties they exhibit. The MOFs used are micro and nanoparticles of Zeolitic Imidazole Framework-8 (ZIF-8), copper based MOF HKUST-1 and chromium based MOF MIL-101. Micro particles of magnesium based MOF Mg-MOF-74 were also looked at as well as cage 3, nano cage 3 and reduced cage 3. Comparable surface areas of the MOFs compared to those quoted in the literature have been obtained. Successful PIM-1/Filler MMMs were synthesised utilising PIM-1 and the fillers outlined above with various loadings of filler. The highest loading achieved was with a 10:6.4 PIM-1/nanoZIF-8 ratio. All MMMs apart from PIM-1/Mg-MOF-74 MMM were homogenous on a macroscale with scanning electron microscopy proving the dispersion of fillers. Gas transport properties of the MMMs were determined using predominantly a time lag method. PIM-1/ZIF-8 MMMs were also tested using a chromatographic method and using a gas sorption experiment. A range of gases were tested including CO2, N2, CH4, O2, He and H2. Ideal selectivities were also calculated with focus on the gas pairs O2/N2, CO2/CH4 and CO2/N2.When comparing the two permeability methods using the PIM-1/nanoZIF-8 MMM, lower permeability results were found from the time lag method. This was concluded to be due to the aging effect brought about by the vacuum used in the time lag method. The chromatographic method produced positive results with high selectivities, breaking Robeson’s upper bound, for the gas pair O2/N2. All other fillers tested showed an increase in permeability and stable selectivity with an increase in the amount of filler. MIL-101 and Cage 3 were the most successful fillers with high permeabilities of 35600 and 37400 Barrer respectively, encroaching on that of PTMSP. Mg-MOF-74 and reduced cage 3 MMM however, had a detrimental effect on the permeability. Aging data was also investigated which showed that for the majority of MMM the permeability followed the trend of PIM-1. microHKUST-1 and cage 3 of 10:3 loading were shown to give promising results with 10000 and 14300 Barrer respectively compared to 7200 Barrer for PIM-1. Although a loss in permeability is seen, it is still above that of PIM-1 at the same point of aging. These results give a positive indication that MMMs have the potential to provide resistance against aging, a major problem in using high free volume polymers in industrial applications.
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Tian, Yuyang. "Synthesis and characterization of crystalline microporous materials : investigation of new synthetic routes." Thesis, University of St Andrews, 2014. http://hdl.handle.net/10023/6371.
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Conventionally, crystalline microporous materials such as zeolites and metal-organic frameworks (MOFs) are synthesized through the hydrothermal route or the trial-and-error approach. Other synthetic strategies may lead to the synthesis of microporous materials with new architectures or interesting properties. The general aim of this thesis is to investigate some new synthetic routes towards crystalline microporous materials. A top-down and post-synthesis method is reported in Chapter 4. Some zeolites are built up by layers and double-4-ring pillars. Germanium is preferentially located in the double-4-ring sites of a zeolite framework and is hydrolytically unstable. The idea of the top-down method is to disassemble these zeolites to the layer structures by dissolving the Ge-containing pillars and reassemble them to a new framework. This method is applied to the germanosilicate IWW and ITH zeolites for the first time. The effects of framework chemical compositions, Ge distributions and disassembling conditions on the top-down treatment process are investigated. The products obtained from the top-down treatment are characterised. An ionic liquid assisted strategy for the synthesis of zeolites is described in Chapter 5. The ionic liquid assisted strategy is a solvent free reaction. The raw materials are transformed to zeolites through a solid state reaction. The ionic liquids are first used as structure-directing agents (SDAs) in this solvent free reaction to replace the expensive quaternary ammonium hydroxide. A TON zeolite is synthesized using 1-ethyl-3-methylimidazolium bromide as the SDA. Moreover, the ionic liquid assisted strategy is considered as a “green chemistry” synthetic route due to the high yield of the zeolites and the minor production of waste water. Many aluminophosphates have been successfully synthesized through ionothermal routes. Most of them are synthesized using 1-alkyl-3-methylimidazolium based ionic liquids. A new ionic liquid, 1-(2-hydroxyl-ethyl)-3-methylimidazolium chloride ([HOEmim]Cl), is prepared and used for the ionothermal synthesis of aluminophosphate materials. A zeolite analogue with the CHA framework has been synthesized. At high synthetic temperatures, the products are large single crystals. The structures of the framework and the SDA are investigated by single crystal diffraction and other characterisation methods. Flexible MOF materials are usually synthesized by a trial-and-error approach. Recently a flexible MOF compound was synthesized using 5-sulfoisophthalic acid (SIP) as the ligand. It was proposed the sulfonate is weakly coordinated to the metal, which brings flexibility to the compound, and the carboxylate groups keep the framework intact. 2-sulfoterephthalic acid (STP) which also contains one sulfonate group and two carboxylate groups is believed to be an alternative ligand for the targeted synthesis of flexible MOFs. In Chapter 7, a MOF compound is synthesized using STP and 4, 4'-bipyridine (Bpy) as ligands to validate the proposed strategy can be generalized. Variable temperature single crystal diffraction analysis solves the structure and reveals a reversible structure transformation upon dehydration and rehydration.
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Schwartz, Heidi Annemarie [Verfasser], Uwe [Gutachter] Ruschewitz, Dominik [Gutachter] Schaniel, and Christoph [Gutachter] Janiak. "Metal-Organic Frameworks as Crystalline Porous Hosts for Photoactive Molecules / Heidi Annemarie Schwartz ; Gutachter: Uwe Ruschewitz, Dominik Schaniel, Christoph Janiak." Köln : Universitäts- und Stadtbibliothek Köln, 2018. http://d-nb.info/1165256169/34.
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Haase, Frederik [Verfasser], and Bettina [Akademischer Betreuer] Lotsch. "Tuning the structure and properties of nitrogen-rich covalent organic frameworks by molecular design and solid state reactions / Frederik Haase ; Betreuer: Bettina Lotsch." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2018. http://d-nb.info/1184202494/34.
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Garzón, Tovar Luis Carlos. "Confining Reactions in a Droplet: Synthesis of MOFs, COFs and Composites using Spray-Drying." Doctoral thesis, Universitat Autònoma de Barcelona, 2018. http://hdl.handle.net/10803/664004.
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Una nueva era en la química de los materiales inició con el descubrimiento de las redes Metal-Orgánicas (MOFs, por sus siglas en inglés) y las redes Orgánicas-Covalentes (COFs, por sus siglas en inglés). En particular, la introducción de la química reticular representó una estrategia revolucionaria que proporcionó a los químicos infinitas oportunidades para diseñar y construir nuevos materiales funcionales con propiedades excepcionales, como su alta porosidad, alta flexibilidad estructural / composicional y bajas densidades (para COF). De hecho, estas propiedades convierten a los MOFs y a los COFs en materiales prometedores para múltiples aplicaciones de interés comercial, que incluyen almacenamiento y separación de gases, catálisis, administración de fármacos, baterías térmicas y sistemas de refrigeración. Estas posibilidades han promovido un ritmo de expansión rápido y explosivo en este campo y, como resultado, la academia y la industria han comenzado a proponer varias iniciativas para la comercialización de estos materiales porosos. Sin embargo, a pesar de estos esfuerzos, la comunidad científica también ha reconocido que el uso de estos materiales podría verse limitado por los desafíos relacionados con sus métodos de producción a gran escala, ya que normalmente se necesitan condiciones severas para sintetizarlos. En este sentido, nuevas estrategias para su síntesis se han desarrollado recientemente. En particular, el método de secado por pulverización ha surgido como una tecnología prometedora para la síntesis de MOF a gran escala. Sin embargo, el secado por pulverización todavía está en sus etapas iniciales y, por lo tanto, hay muchos desafíos que deben superarse.
En esta tesis, hemos desarrollado nuevas estrategias para sintetizar MOFs. En particular, hemos desarrollado un nuevo método para la síntesis de MOFs basados en unidades de construcción secundarias. También, hemos demostrado que el método de secado por atomización acoplado a un sistema de flujo-continuo puede ser usado no solo para sintetizar MOFs, sino también para incorporar especies funcionales. De este modo, se introduce una nueva ruta para la síntesis de materiales compuestos. En esta tesis, se extiende el uso de la técnica de secado por pulverización a la química covalente. De esta manera, se muestra que diferentes iminas pueden ser sintetizadas a partir de reacciones de condensación entre aldehídos y aminas. Además, también demostramos que los MOFs pueden ser fácilmente modificados. De esta manera, usando la técnica de secado por pulverización, mostramos la modificación post-sintética de dos MOFs, el amino-terminal UiO-66-NH2 y el aldehído-terminal ZIF-90. Además, también se demuestra que las reacciones de condensación pueden extenderse para la síntesis de COFs. Así, demostramos que superestructuras esféricas creadas a partir del ensamblaje de nanocristales de COF pueden ser obtenidas en un proceso de dos pasos, que incluye el secado por pulverización seguido de una transformación amorfo-cristalino del material. Además, se demuestra como las superestructuras resultantes pueden ser utilizadas para encapsular diferentes materiales, tales como moléculas fluorescentes y nanopartículas magnéticas.A new age in materials chemistry started with the discovery of Metal-Organic Frameworks and Covalent-Organic frameworks. In particular, the introduction of reticular chemistry represented a revolutionary strategy that gave chemists infinite opportunities toward the design and construction of novel functional materials with exceptional properties, such as their high porosity, high structural/compositional flexibility and low densities (for COFs). Indeed, these properties render MOFs and COFs as promising materials for multiple applications of commercial interest, including gas storage and separation, catalysis, sensing, drug delivery, water harvesting and adsorptive heat transformation systems. These possibilities have promoted a rapid and explosive pace of expansion in this field and as a result, academia and industry have begun to propose several initiatives towards the commercialization of these porous materials. However, despite these efforts, the scientific community has also recognized that the use of these materials could be limited by the challenges pertaining to their production methods at large scale since harsh conditions are usually needed to synthesize them. In this sense, novel approaches for their synthesis have been developed recently. In particular, the spray-drying method has emerged as a promising technology for the synthesis of MOFs at large scale. However, spray-drying is still in its embryonic stage and therefore, there are many challenges that need to be overcome. In this Thesis, we have developed new strategies to synthesize MOFs. In particular, we describes a new methodology based on coupling two processes —spray-drying and continuous flow— for continuous synthesis of MOFs assembled from high-nuclearity secondary building units (SBUs). In addition, we demonstrated that the spray-drying-continuous flow method can be used not only to synthesize MOF superstructures but also to incorporate functional species, thereby providing a new route for the synthesis of MOF-based composites. In this thesis, we extend the use of spray-drying technique to covalent chemistry. To this end, we show that different imines can be synthesized from Schiff-base condensation reactions between discrete aldehydes and amines using the spray-drying. We also show that this chemistry can be extended to post-synthetically modify MOFs. For example, we show the post-synthetic modification of two MOFs, the amine-terminated UiO-66-NH2 and the aldehyde-terminated ZIF-90. Moreover, we demonstrate that the Schiff-base condensation reactions can be extended to the synthesis of COFs. Thus, we prove that spherical superstructures made from the assembly of imine-based COF nanocrystals can be obtained by combining the spray-drying technique with a dynamic covalent chemistry process. In addition, we show that this methodology enables the integration of other functional materials such as dyes and magnetic nanoparticles into these superstructures forming COF-based composites.
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Wang, Zhiyong, Gang Wang, Haoyuan Qi, Mao Wang, Mingchao Wang, SangWook Park, Huaping Wang, et al. "Ultrathin Two-Dimensional Conjugated Metal-Organic Framework Single-Crystalline Nanosheets Enabled by Surfactant-Assisted Synthesis." Royal Society of Chemistry, 2020. https://tud.qucosa.de/id/qucosa%3A72508.
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Two-dimensional conjugated metal-organic frameworks (2D c-MOFs) have recently emerged for potential applications in (opto-)electronics, chemiresistive sensing, and energy storage and conversion, due to their excellent electrical conductivity, abundant active sites, and intrinsic porous structures. However, developing ultrathin 2D c-MOF nanosheets (NSs) for facile solution-processing and integration into devices remains a great challenge, mostly due to unscalable synthesis, low yield, limited lateral size and low crystallinity. Here, we report a surfactant-assisted solution synthesis toward ultrathin 2D c-MOF NSs, including HHB-Cu (HHB=hexahydroxybenzene), HHB-Ni and HHTP-Cu (HHTP=2,3,6,7,10,11-hexahydroxytriphenylene). For the first time, we achieve single-crystalline HHB-Cu(Ni) NSs featured with a thickness of 4-5 nm (~8-10 layers) and a lateral size of 0.25-0.65 μm², as well as single-crystalline HHTP-Cu NSs with a thickness of ~5.1±2.6 nm (~10 layers) and a lateral size of 0.002-0.02 μm². Benefiting from the ultrathin feature, the synthetic NSs allow fast ion diffusion and high utilization of active sites. As a proof of concept, when serving as a cathode material for Li-ion storage, HHB-Cu NSs deliver a remarkable rate capability (charge within 3 min) and long-term cycling stability (90% capacity retention after 1000 cycles), superior to the corresponding bulk materials and other reported MOF cathodes.
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Juvenal, Frank. "Polymères de coordination luminescents 1D et 2D avec des ligands rigides contenant du Pt(II) montrants des propriétés d’adsorption du CO2." Mémoire, Université de Sherbrooke, 2017. http://hdl.handle.net/11143/10578.
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La conception de nouveaux matériaux fonctionnels a une longue histoire. Durant les deux dernières décennies, le domaine des polymères organiques et inorganiques a attiré l'attention des chercheurs. Plus important encore, les matériaux poreux tels que les Metal Organic Frameworks (MOFs), en anglais, Covalent Organic Frameworks (COFs), en anglais, ainsi que des polymères de coordination poreux sont maintenant étudiés de manière intensive en raison de leurs applications potentielles, comprenant le stockage de gaz, la séparation de gaz, la catalyse et la détection. D'un autre côté, les polymères contenant du Pt ont montré l'application potentielle dans les cellules solaires et les diodes électroluminescentes. Le mémoire est divisé en trois sections principales présentant des résultats nouveaux. Dans la première section, le chapitre 2 traite essentiellement de la formation de polymères de coordination (CP) avec des sels CuX (X = Cl, Br, I) et trans-[p-MeSC6H4C≡C-Pt(PMe3)2-C≡CC6H4SMe] (L1), soit dans le PrCN ou PhCN. Les polymères résultants sont soit 2D (bidimensionel) ou 1D (unidimensionel). Cependant, en presence de PrCN ou de PhCN, le CP 2D obtenu avec le CuBr n'a pas incorporé de solvant dans ses espaces vides. D'autre part, le CP 2D et le reste des CP 1D obtenus avaient soit des molécules de solvant de cristallisation dans leurs cavités ou coordonnés au cuivre sur la chaîne. Les unités cuivre-halogénures étaient soit des rhomboïdes Cu2X2 ou le cubane Cu4I4. Leurs mesures photophysiques en présence et en l'absence de molécules de solvant de cristallisation ont été effectuées. En outre, la porosité du CP a été évaluée par BET (N2 à 77 K). Le vapochromisme du CP 2D sans solvant et des CP 1D ont été étudiés, ainsi que les mesures de sorption du CO2 ont été effectuées. De plus, nous avons utilisé CuCN et L1 dans MeCN pour former de nouveaux CP’s. Ceci est rapporté dans la deuxième section, le chapitre 3. Le CP obtenu était inattendu : L1 s’est rompu et du cyanure CN‾ s’est coordonné sur le Pt. Ceci a conduit à la formation d’un CP 1D zigzag. Généralement, les CP sont formés avec L1 via des liens Cu-S ou/et Cu([éta]2-C≡C), mais pas dans le cas du CuCN qui lui forme une chaîne 1D (CuCN)n où le L1 rompu se lie avec cette chaîne via un lien Cu-N. Les propriétés photophysiques et de stabilité thermique ont été étudiées. La troisième section (Chapitre 4) traite d'une exploration des CP formés par la reaction des sels CuX (X = Cl, Br, I) et le trans-[p-MeSC6H4C≡C-Pt(PMe3)2-C≡CC6H4SMe] (L1) ou le trans-[p-MeSC6H4C≡C-Pt(PEt3)2-C≡CC6H4SMe] (L2) dans du MeCN afin de trouver des tendances. L'utilisation de L1 a donné lieu à un CP 2D ou 1D CPs avec le MeCN piégé à l'intérieur des cavités, il y a de l’espace vide. L2 a conduit uniquement à des CP 1D sans molecules de solvant de cristallisation. Des analyses thermogravimétriques, photophysique et des mesures d’adsorption de gaz (uniquement pour ceux avec du solvant) ont été étudiées.Abstract: The design of new functional materials has a long history. For the past two decades, the field of organic and inorganic polymers has attracted attention of researchers. More importantly, porous materials such as Metal Organic Frameworks (MOFs), Covalent Organic Frameworks (COFs) as well as porous coordination polymers are now being intensively studied due to their potential applications including gas storage, gas separations, catalyst and sensing. On another hand, Pt-containing polymers have shown potential applications in solar cells and light emitting diodes. The masters’ thesis is mainly divided into three main sections presenting new results. In the first section; Chapter 2 mainly discusses the formation of coordination polymers with CuX salts (X= Cl, Br, I) and trans-[p-MeSC6H4C≡C-Pt(PMe3)2-C≡CC6H4SMe] (L1), in either PrCN or PhCN. The resulting polymers obtained were 2D (bidimensional) CPs or 1D (unidimensional) CPs in all cases. However, 2D CPs obtained when CuBr salt is used by either using PrCN or PhCN did not incorporate the solvents in their cavities. On the other hand, the 2D CP and the rest of 1D CPs obtained had either the crystallization molecules in the cavities or coordinated to the copper cluster. The copper-halide clusters were either the rhomboids Cu2X2 fragments or the step cubane Cu4I4. The photophysical measurements in the presence and absence of solvent crystallization molecules were performed. In addition, the porosity of the CPs was evaluated by adsorption isotherms. The vapochromism of the solvent-free 2D and 1D CPs were investigated as well as CO2 sorption measurements were perfomed. Furthermore, we then attempted to use CuCN and L1 in MeCN which is reported in the second section as Chapter 3. The obtained CP was unexpected as L1 broke and a cyanide (CN‾) ion coordinated to the Pt atom leading to the formation of zigzag 1D CP. The coordination bonds Cu-S or/and Cu([eta]2-C≡C) were generally observed with L1, but not in the CuCN case. Instead a 1D chain of (CuCN)n was made and the broken L1 now binds the chain via a Cu-N bond. The photophysical and thermal stability properties were studied. Lastly, the third section, Chapter 4 deals with a potential predictability of CP formation by using CuX salts (X= Cl, Br, I) and either trans-[p-MeSC6H4C≡C-Pt(PMe3)2-C≡CC6H4SMe] (L1) or trans-[p-MeSC6H4C≡C-Pt(PEt3)2-C≡CC6H4SMe] (L2) in MeCN as the solvent. The use of L1 resulted in either 2D or 1D CPs with the MeCN trapped inside of the cavities while L2 resulted in 1D CPs without MeCN being present in their cavities. The thermogravimetric, photophysical as well as gas sorption measurements (only for those with crystalisation molecules) were perfomed.
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Werner, Veronika [Verfasser], and Paul [Akademischer Betreuer] Knochel. "Regioselective functionalization of aromatics and heterocycles bearing a bis-silyl-methyl group, one-pot procedure for the preparation of tertiary amines via iminium ions and preparation of new benzodithiophene building blocks for covalent organic frameworks / Veronika Werner ; Betreuer: Paul Knochel." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2015. http://d-nb.info/1127528041/34.
Full text
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Assi, Hala. "Nouveaux polymères de coordination à base de titane et de dérivés phénoliques." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLV072/document.
Full textAbstract:
Les solides hybrides poreux ou les « MOFs » sont l'une des classes les plus récentes de polymères de coordination poreux cristallins. En raison de la variété de leur structure et leur composition, Ils sont actuellement considérés comme des candidats prometteurs dans divers domaines (le stockage de gaz, la séparation des fluides, la catalyse, la biomédecine…). Cependant, la littérature sur l'activité photocatalytique de ces solides n’a commencé à s’exploser que très récemment, bien que l’utilisation de ces matériaux comme photocatalyseurs hétérogènes soit avantageux en comparaison avec les semi-conducteurs classiques. Compte tenu des propriétés photocatalytiques bien établies de TiO2, il semble logique de se concentrer sur le titane(IV) pour la conception de nouveaux MOFs pour de telles applications. Néanmoins, en raison de la difficulté de contrôler la réactivité de cet ion métallique en solution (en particulier hors des conditions très acides), très peu de MOFs à base de titane ont été décrits, parmi les MOFs nombreux connus dans la littérature. Ainsi, l'obtention de solides cristallins à base de titane dans l'eau et en milieu basique reste un défi majeur dans ce domaine. Dans nos travaux, certaines stratégies ont été suivies afin de bénéficier des avantages de l’utilisation des cations Ti4+ et parallèlement confronter leurs limitations en se focalisant sur l'exploration de la chimie de ces cations (alcoxydes de titane, complexes et oxo-clusters) avec divers ligands polytopiques, en particulier les dérivés hydroxycarboxylates et polycatécholates pour la conception de nouveaux solides hybrides poreux stables à base de titane. Ces ligands présentent des avantages importants par rapport aux carboxylates purs, tels que la diversité structurale potentiellement plus élevée, les liaisons Ti-O plus fortes conduisant à une stabilité chimique améliorée en milieu basique, et une large absorption dans le visible assurée par un transfert de charge ligand-métal. D'autre part, l'utilisation des complexes moléculaires ou des oxo-clusters de titane sera une opportunité prometteuse dans le but de contrôler l'hydrolyse spontanée et la réactivité élevée des ions Ti4+. En privilégiant la synthèse solvo- et hydrothermale à l'aide du « système haut-débit », ces stratégies ont conduit à l’obtention de nouveaux solides cristallins (composés moléculaires et polymériques 1D /2D /3D). La synthèse, la caractérisation structurale au travers de la combinaison de différentes techniques (diffraction des rayons X, analyse thermogravimétrique, spectroscopie IR, RMN du solide, mesure de sorption...), l'étude de certaines propriétés et l’étude préliminaire de l’activité photocatalytique (production de dihydrogène de l’eau) de ces nouveaux solides seront ainsi discutées dans ce manuscritCrystalline Metal-Organic Frameworks MOFs are one of the most recent classes of crystalline porous coordination polymers. Due to the variety of their structure and composition, they are currently considered as promising candidates in various domains (gas storage, fluid separation, catalysis, biomedicine…). However, the literature on the photocatalytic activity of these solids has exploded only very recently, although the many advantages of using these materials as heterogeneous photocatalysts in comparison with classical semiconductors. Considering the well-established photocatalytic properties of TiO2, it seems logical to focus on titanium in order to design new MOFs for such applications. Nevertheless, because of the difficulty in controlling the reactivity of these ions in solution (especially out of the very acidic conditions), very few crystalline titanium-based MOFs have been described, among the numerous MOFs known in the literature. Thus, obtaining titanium-based MOFs in water and basic medium remains a big challenge. In our work, some strategies has been followed in order to benefice from the advantages of the titanium ions and at the same time confront their limitations by focusing on the exploration of the chemistry of Ti4+ ions (titanium alkoxides, complexes and oxo-clusters) with various polytopic ligands, especially hydroxycarboxylate and polycatecholate derivatives in order to design new stable titanium-based MOFs. Such ligands provide important advantages in comparison with pure carboxylates, such as a potentially higher structural diversity, stronger Ti-O bonds leading to an enhanced chemical stability in basic medium, and a strong absorption in the visible range ensured by ligand to metal charge transfer. On the other hand, the use of titanium molecular complexes or oxo-clusters will be a promising opportunity in order to control the spontaneous hydrolysis and the high activity of Ti4+ ions. By privileging the solvo- and hydrothermal synthesis using the «high-throughput system», these strategies lead to obtain new crystalline solids (molecular and 1D/2D/3D polymeric compounds). The synthesis, the structural characterization by a combination of different technics (X-ray diffraction, TGA analysis, IR spectroscopy, Solid State NMR, sorption measurement…), the study of some properties and the preliminary photocatalytic experiments (water splitting reaction) of these new solids will be discussed in this manuscript
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Santos, Rúben Filipe Pinto. "Modulation of crystalline structures of metal-organic frameworks." Master's thesis, 2021. http://hdl.handle.net/10773/32751.
Full textAbstract:
Over the last years, the major focus on MOF research field has been synthesis
and possible application of these materials. One of the most important
steps of this process is characterization. In order to do that, researchers
rely on techniques such as DRX (Diffraction X-Ray) to perform modulation
of experimental data and structure refinements. However, these techniques
are often dependent on parameters which aren't always easy to define. This
fact results in situations where sometimes researchers don't know exactly
the crystalline structures of some materials.
The objective of this dissertation is to lay the first steps on the creation of
a modelling program that is able to generate a library of possible structures
that can be compared with experimental data, thus obtaining a solution
for the aforementioned problem. Being the connection between Mathematics
and MOFs a vastly unexplored field, the first approach was to explore
chemical structures that possessed well documented connections to Mathematics.
In this context, diverse mathematical aspects of fullerenes were
explored, such as applications of Graph Theory and Geometry.
Given the symmetrical nature of MOFs, concepts such as Symmetry, Frieze
and Wallpaper groups were studied, as well as Crystallography with the
study of the different types of lattice. A statistical study on the nature and
possible distortions of the coordination spheres of metal centers(with focus
on the first series of transition metals) present in MOF structures was also
made.O maior foco da investigação da área de MOFs nos últimos anos tem sido a sintese e possíveis aplicações destes materiais. Uma das etapas importante desse processo é a caracterização dos mesmos. Para isso, os investigadores recorrem a técnicas como DRX (Diffraction X-Ray) para efetuar modelação dos dados experimentais e refinar as estruturas. Porém estas técnicas muitas vezes estão dependentes de parâmetros que nem sempre são fáceis de definir. Este facto leva a que os investigadores por vezes não conheçam com exatidão as estruturas cristalinas de alguns materiais. O objetivo desta dissertação é o de dar os primeiros passos na criação de um programa de modulação que gere uma biblioteca de possíveis estruturas que possam ser depois ser comparadas com os dados experimentais, obtendo assim uma possível solução para este problema. Sendo o campo da Matemática aplicada aos MOFs um campo praticamente inexplorado, a primeira abordagem foi a de explorar estururas químicas com ligações à Matemática bem documentadas. Neste contexto surgiram os Fulerenos onde foram estudados diversos aspetos matemáticos como aplicações da Teoria dos Grafos e de Geometria. Dada a natureza simétrica dos MOFs, foram também explorados conceitos de Simetria como os grupos de frisos e papéis de parede, bem como de Cristalografia com o estudo dos diferentes tipos de reticulados. Procedeu-se ainda a um estudo estatístico sobre a natureza e possíveis distorções das esferas de coordenação dos centros metálicos presentes nos MOFs (focado na primeira serie dos metais de transição).
Mestrado em Matemática e Aplicações
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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.
Full textAbstract:
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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Abuzeid, Hesham Rashed, and 何杉. "Construction of Covalent Benzoxazine/Organic Frameworks for CO2 Uptake and Supercapacitors Applications." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/vk8v3v.
Full textAbstract:
碩士國立中山大學
材料與光電科學學系研究所
107
In this thesis, we report the first covalent benzoxazine framework (CBF-1) in addition to new dual-pore and single-pore Covalent organic frameworks and their application for CO2 uptake and supercapacitor. First, Covalent benzoxazine framework (CBF-1) was synthesized via a solvothermal method using trifunctional aminophenyl triazine (TAPT), and trifunctional hydroxyphenyl triazine (THPT) paraformaldehyde through Mannich condensation reaction. This new CBF-1 underwent thermal cross-linked curing to generate a highly cross-linked CBF (CCBF-1), which, with carbonization followed by KOH activation, was converted into nitrogen-doped microporous carbon (N-DMC). The thermal curing, carbonization, and activation for CBF-1 have dramatically enhanced the thermal properties and BET surface area. Interestingly, the formed N-DMC exhibited a spherical morphology with excellent thermal stability (up to Td5 of 663 ºC and char yield of 85%), high BET surface areas (up to 1469 m2 g-1), and pore size of 2.07 nm. The thermal transformation from CBF-1 to CCBF-1, then to N-DMC directly enhanced the CO2 capture and electrochemical capacitance. N-DMC showed excellent CO2 capture capacities of 3.85 and 7.46 mmol/g at 298 and 273 K, respectively. Moreover, N-DMC showed high electrochemical capacitance of 185 Fg-1 at current density 1.0 Ag-1, and excellent stability performance of 86% average retention at 20 Ag-1 after 4000 cycles. In addition, we report a conceptual strategy to study the effect of supramolecular interactions on the topological regulating of 2D COFs as a new technique to manage their properties. Our strategy was achieved by introducing pristine and substituted diamines monomers; Benzidine (BD) and 1,4-dihydroxybenzidine (DHBD) into the skeleton of bicarbazole monomer. The newly designed microporous bicarbazole COFs (Cz-BD and Cz-DHBD) with 1D open micropores were designed using a [C2 + C2] topology diagram and successfully synthesized via a Schiff-base condensation reaction of tetraformyl-bicarbazole as C2 knot and aromatic diamines as C2 linker. The resulting COFs have two different topologies, Cz-BD bears a single-pore with tetragonal structure, while Cz-DHBD has a kagome structure bearing two different kinds of pores; one is hexagonal and the other is triangular. These COFs feature high crystallinity, aqueous and organic and solvents stability, large surface area and high porosity with open one-dimensional (1D) microporous channels and densely aligned π-arrays of crystalline sheets. These COFs exhibited synergistic structural effects and achieved ultrahigh-performance of CO2 uptake.
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Kuo, Cheng-Han, and 郭承翰. "Synthesis of Novel Two Dimensional Covalent Organic Frameworks and Their Gas Adsorption/Desorption Properties." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/7b77z2.
Full textAbstract:
碩士國立中山大學
材料與光電科學學系研究所
106
In this study, we synthesized a series of related monomers and polymers based on covalent organic frameworks (COFs) materials. In the first place, we prepared different five monomer derivatives, including TPA-3NH2, TPT-3NH2, TPA-3CHO, TPP-3CHO, and TPT-3CHO, which were characterized by Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopies. Secondly, we used the condensation polymerization to synthesize six different COFs via the Schiff base reaction to possess various two-dimensional crosslink structures, named TPA-TPA-COF (COF-1), TPA-TPP-COF (COF-2), TPA-TPT-COF (COF-3), TPT-TPA-COF (COF-4), TPT-TPP-COF (COF-5) and TPT-TPT-COF (COF-6), based on FTIR, TGA, solid state nuclear magnetic resonance (solid state NMR), elemental analysis (EA), powder X-ray diffractometer (PXRD), and BET analyses. The successfully synthesized of these COFs could be confirmed by using FTIR and solid state NMR analyses. All degradation temperatures of COFs are higher than 480 oC based on TGA analyses, indicating that the planar molecular for center group in the COFs make the structure having more stable and better thermal stability. The well-defined crystalline structures were observed of these COFs with hexagonal packed cylinder based on PXRD analyses. Finally, we utilized the surface area and pore size distribution to make further analyses about the relative N2(g) and CO2(g) sorption of different functional groups for center structures. We can observe that the capacity of carbon dioxide (CO2) capture was improved upon increasing the nitrogen content and planarity in COFs.
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Costa, Sebastião Melo Refoios da. "Synthesis and characterization of new zeolite membranes and crystalline meta-organic frameworks." Master's thesis, 2018. http://hdl.handle.net/10773/25514.
Full textAbstract:
The use of membranes for the separation of gas mixtures has gained
great importance owing to its advantages when compared to
conventional separation processes, such as moderate energy
consumption and simplicity of operation. Although polymer
membranes dominate the market, they are limited by relatively low
operating temperatures and selectivities. Inorganic membranes are
characterised by high thermal, chemical and mechanical stabilities,
and are particularly attractive for separation purposes. Recently,
crystalline metal-organic frameworks (MOFs) have been subject of
intense research, since their structure is composed of organic linkers
and inorganic clusters, revealing characteristics of both elements,
such as flexibility and better control of the size distribution of the
pores.
A central aim of this dissertation was the synthesis and subsequent
characterisation of inorganic microporous zeolite membranes and, in
parallel, MOFs. In the whole, fifteen membranes have been
synthesized. The structure and morphology of the most promising
membranes were studied by X-ray diffraction (XRD) and scanning
electron microscopy (SEM) techniques. With regard to the dynamic
characterisation, it was accomplished carrying out pure gas
permeation assays at fixed and programmed temperature using
different gases (i.e., with distinct kinetic diameters).
In what concerns the zeolite membranes supported on α-alumina
tubes, a secondary growth method was implemented, followed by
hydrothermal synthesis. The effect of the synthesis time and the
presence of rotation were studied, being concluded that longer times
give rise to better membranes, and the absence of rotation results in
defects over the structure. The hydrophilic character of the
crystalline layer was proved by preliminary heating-cooling cycles
assays. The best membrane (labelled MFI93) was studied in detail
in the temperature range of 25-110 °C using He, N2 and O2. It was
possible to confirm that the permeance and the kinetic diameter of
the gases are related: helium, which has the smallest diameter,
attained higher permeance values. From the temperatureprogrammed
permeation tests, it was found that at low temperatures
the viscous flow mechanism has an important contribution to the gas
transport. Its influence is progressively reduced with increasing
temperature, becoming the activated gaseous diffusion the main
transport mechanism. The subsequent characterisation of MFI93
membrane by XRD and SEM confirmed the preparation of a
continuous ZSM-5 layer inside the support tube. In parallel, the synthesis of MOFs membranes was also tested. The
non-deposition of uniform coatings was evidenced by the permeance
dynamic characterisation of such membranes, since no gas
separation was observed. Nonetheless, the deposition of small
crystals of ZIF-8 on the inner side of support was confirmed by XRD
and SEM analysisA utilização de membranas para a separação de misturas gasosas tem ganho grande importância devido às suas vantagens quando comparadas com processos de separação convencionais, como o moderado consumo energético e simplicidade de operação. Apesar de as membranas poliméricas dominarem o mercado, estas são limitadas por temperaturas de operação e seletividades relativamente baixas seletividades. As membranas inorgânicas, por possuírem elevadas estabilidades térmica, química e mecânica, tornam-se particularmente interessantes para processos de separação. Recentemente, as redes metalo-orgânicas cristalinas (MOFs), têm sido alvo de grande investigação, já que a sua estrutura é composta por uma componente orgânica e outra inorgânica, revelando características típicas de ambos os elementos, como flexibilidade e maior controlo na distribuição do tamanho dos poros. Na presente dissertação pretendeu-se sintetizar e, posteriormente, caracterizar, membranas inorgânicas microporosas de zeólitos e, paralelamente, MOFs. No total, quinze membranas foram preparadas. A estrutura e morfologia das membranas mais promissoras foram estudadas pelas técnicas de difração de raios-X (DRX) e de microscopia eletrónica de varrimento (SEM). A caracterização dinâmica foi realizada por ensaios de permeação de gases puros a temperatura fixa e programada, usando diferentes gases (i.e., moléculas com diâmetros cinéticos distintos). Relativamente às membranas zeolíticas, suportadas em tubos de α- alumina, recorreu-se ao método de crescimento secundário, seguido de síntese hidrotérmica. Estudou-se o efeito do tempo de síntese e da presença de rotação durante a mesma. Concluiu-se que com tempos de síntese superiores são preparadas membranas melhores, enquanto a ausência de rotação origina defeitos na estrutura. Comprovou-se o caráter hidrofílico das redes cristalinas através de ensaios de aquecimento-arrefecimento preliminares. A melhor membrana (denominada por MFI93) foi estudada em maior detalhe na gama de temperaturas de 25-110 ºC utilizando He, N2 e O2. Confirmou-se que a permeância e o diâmetro cinético dos gases relacionam-se: hélio, que possui o menor diâmetro, obteve maiores valores de permeância. Pelos testes de permeação a temperatura programada, verificou-se que para baixas temperaturas o mecanismo de escoamento viscoso contribui para o transporte do gás. A sua contribuição diminui progressivamente com o aumento da temperatura, passando a difusão gasosa ativada a ser o mecanismo de transporte dominante. Através da caracterização por DRX e SEM provou-se a preparação de uma camada contínua de ZSM-5 no interior do suporte. Em paralelo, procedeu-se à síntese de redes cristalinas de MOFs. A não deposição de uma camada uniforme foi evidenciada pela caracterização dinâmica das amostras, já que não se verificou qualquer separação. Porém, confirmou-se a formação de pequenos cristais de ZIF-8 na superfície interna do tubo, através de análises de DRX e SEM
Mestrado em Engenharia Química
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Troschke, Erik. "Novel Synthetic Pathways for Tailored Covalent Triazine Frameworks with Catalytic and Electrochemical Applications." Doctoral thesis, 2018. https://tud.qucosa.de/id/qucosa%3A32350.
Full textAbstract:
For many applications of industrial relevance, solids providing enhanced porosity such as activated carbons or zeolites have been the key drivers of progress in the past century. Albeit these materials marked an entire era of research, scientists have contributed immense effort to mimic porosity in an artificial way. A rich field to address this challenge is polymer chemistry. Especially covalent triazine frameworks (CTFs), which are exclusively built up from organic matter connected by covalent bonds, have proliferated in the last 10 years and provide remarkable chemical and thermal stability.
Within this thesis, a salt templating method for the synthesis of mesoporous CTF materials was developed that applies binary salt mixtures of ZnCl2 (the conventional reaction medium) in combination with alkali halides. In contrast to existing synthetic concepts that induce mesoporosity via high temperature treatment (up to 700 °C), salt templating was conducted at moderate temperatures (300 – 450 °C) and significantly avoided carbonisation as well as nitrogen loss. By applying this new method, salt templated materials with a four-fold increased total pore volume (CTF 1_LiCl: 2.1 cm3 g-1 vs. conventional CTF-1: 0.5 cm3 g-1) and an almost complete retention of the specific surface area (1320 m2 g-1 vs. 1440 m2 g-1) could be synthesised.
Another aspect of this thesis dealt with a novel approach to generate CTF materials in a solvent-free, time-efficient and scalable manner. To this end, a mechanochemical synthesis route was developed that makes use of the Friedel-Crafts alkylation to generate CTF materials from cyanuric chloride, serving as triazine node, and electron-rich aromatic compounds as linker molecules. By this method, permanently porous materials (up to 570 m2 g-1) could be synthesised from various monomers with different length and geometry. The syntheses could be conducted within two hours and on a gram scale, thus significantly exceeding known methods in terms of time-efficiency and scalability.
Besides these synthetic concepts, three other chapters covered the area of potential applications for CTF materials. To this end, novel CTF materials were synthesised and assessed towards their suitability for use in energy storage systems such as lithium sulfur battery or supercapacitor.
In analogy to SPAN, a sulfur containing conductive poly(acrylonitrile) polymer, CTFs containing covalently bound sulfur (S@CTF) were anticipated as promising cathode material in the lithium sulphur battery. Following the synthesis of a variety of different materials, a particular focus was set on determining the impact of sulfur attachment on the porosity and on illustrating the bonding situation of sulfur within the porous host matrix. Elemental analysis revealed that the highest sulfur loadings (33 w%) were obtained for the CTF samples obtained at the lowest synthesis temperature (500 °C). These findings were in agreement with nitrogen adsorption experiments that showed a reduced porosity after sulfur attachment for each material and the largest percental drop of the total pore volume for those samples with the highest sulfur loadings. XPS investigations suggested the presence of C-S species in the sulfur treated materials and supported the formation of covalently bound sulfur. Whereas the synthesis of S@CTF materials was successful, the electrochemical characterisation in a carbonate-based electrolyte revealed a substantial capacity loss after only a few cycles, which was probably due to a loss of active material and underlined that confinement of sulfur might be the key to obtain cathodes with increased cycling stability.
In this thesis, a novel pyridine-based CTF material was synthesised, which showed beneficial nitrogen doping and a tuneable porosity by careful choice of the reaction temperature (Scheme 3b). An in-depth characterisation by means of argon physisorption, X-ray photoelectron and Raman spectroscopy was conducted. Thereby, the structural changes upon thermal treatment were carefully investigated and interpreted. The non-purified CTFs – still containing large amounts of ZnCl2 – were directly processed into supercapacitor electrodes. Herein, ZnCl2 was serving two purposes: it acted as a porogen during the CTF synthesis (surface areas up to 3100 m2 g-1 were obtained) and as a precursor for an in situ generated aqueos electrolyte. It was demonstrated that this methodology bypasses extensive washing and more importantly, the findings gained from the electrochemical characterisation matched the structural indications from the XPS experiments. Thus, without purifying the material in advance, this method allowed for estimating the materials’ properties based on its behaviour as supercapacitor.
In the last part, a purely CTF-based organocatalyst that benefits from a monomer bearing a catalytically active functionality was synthesised by introducing a charged cationic imidazolium moiety into a microporous covalent triazine framework. A finely adjusted synthetic protocol enabled the structural retention of the thermally labile imidazolium motif, whose successful integration was proven by an in-depth structural characterisation, applying solid-state 1H MAS NMR, XPS and FT-IR spectroscopy. If applied as heterogeneous organocatalyst, the imidazolium-based CTF was active in the carbene-catalysed Umpolung reaction, thus providing clear evidence of an intact structure.
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Hong, Ying-Hui, and 洪穎慧. "Strategic Design of Two-Dimensional Covalent Organic Frameworks for High-Performance Supercapacitor and Gas Storage Applications." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/e2axeb.
Full textAbstract:
碩士國立中山大學
材料與光電科學學系研究所
107
Covalent organic frameworks (COFs) are new class of crystalline porous materials with high surface area and thermal stability. Recently, COFs have gained significant scientific attention due to their potential applications for gas and energy storage. In this study, we report the design and construction of four keto-enamine-based covalent organic frameworks; TFP-TPB, TFP-TPA, TFP-TPP, and TFP-Car COFs through the Schiff-base condensation reaction between 1,3,5-triformylphloroglucinol (TFP) and 1,3,5-tris(4-aminophenyl)benzene (TPB-3NH2), tris(4-aminophenyl)amine (TPA-3NH2), 2,4,6-tris(4-aminophenyl)pyridine (TPP-3NH2), and 9-(4-aminophenyl)-carbazole-3,6-diamine (Car-3NH2) under solvothermal conditions, respectively. The chemical structures of the prepared COFs were confirmed using Fourier transform infrared (FTIR) spectroscopy, solid state 13C CP MAS NMR spectroscopy, and elemental analysis. The resultant COFs exhibited high BET surface area up to ~ 686 m2/g, excellent crystallinity, and thermal stability up to 475 ℃. For applications, our synthesized COFs exhibited high-performance capacities for supercapacitor and gas storage. TFP-TPA, TFP-TPP, and TFP-Car COFs synthesized from nitrogen-content building monomers; TPP-3NH2, TPA-3NH2, and Car-3NH2 exhibited higher CO2 uptake capacities than TFP-TPB COF synthesized from TPB-3NH2. Moreover, the synthesized COFs exhibited excellent electrochemical properties because of their keto-enamine and conjugated structures containing redox-active triphenylamine groups.
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Bhattacharya, Saurav. "Syntheses Structural Transformations, Magnetism, Ferroelectricity and Proton Conduction of Metal Organic Frameworks (MOF) Compounds." Thesis, 2015. http://etd.iisc.ernet.in/2005/3546.
Full textAbstract:
The past few decades have witnessed an almost exponential increase in interest in the field of metal organic frameworks (MOFs), which can be evidenced from the large number of scientific articles being published routinely in this area.
The MOFs are crystalline hybrid materials built via the judicial use of inorganic
metal ions and organic linkers, thereby bridging the gap between purely inorganic
and organic materials. The structural versatility and the potential tunability of the MOFs imparts unique physicochemical and thermomechanical properties, which have
rendered them immensely useful in the branches of chemistry, material science,
physics, biology, nanotechnology, medicine as well as environmental engineering.
The MOFs have been shown to be promising as materials for gas storage and separation, sensors, ferroelectric and non-linear optical materials, magnetism, catalysis, drug delivery etc and researchers have been devising strategies to utilize
the MOFs to tackle a number of global challenges of the twenty-first century.
A survey of the literature reveals that the linear organic linkers, 1,4-
benzenedicarboxylic acid (BDC) and 4,4’-biphenyldicarboxylic acid (BPDC), have been
the organic linkers of choice for the construction of stable, porous and multifunctional MOFs. The aim of this thesis has been to monitor the effect that the presence of a functional group in between the benzene rings of the BPDC would have on the overall structures and the properties of the MOFs. Thus, as part of the investigations, the preparation of the MOF compounds using 4,4’-sulfonyldibenzoic acid (SDBA) and 4,4’-
azodibenzoic acid (ABA) have been accomplished. Along with the conventional
hydrothermal and solvothermal synthetic techniques, the liquid-liquid biphasic
reaction method was also utilized for the synthesis of some of the compounds. The
structures of the compounds were ascertained from single crystal X-ray diffraction
technique. Proton conductivity studies were performed on Mn based porous MOFs
using AC impedance spectroscopy. The ferroelectric behavior in a Co based porous
MOF was established using dielectric and polarization vs electric field measurements.
The labile nature of the lattice solvent molecules was established utilizing single
crystal X-ray diffraction studies and water sorption experiments. In addition, the site
selective substitution in a homometallic MOF and the subsequent conversion to a
mixed-metal spinel oxide upon thermal decomposition, have also been studied.
Chapter 1 of the thesis is a brief overview of the metal organic framework compounds and summarizes the various important structures that have been reported in literature and the interesting properties that they exhibit. In chapter 2, the proton conductivity behavior, solvent mediated single crystal to single crystal (SCSC) and related structural transformations in a family of Mn and Co based porous MOFs with SDBA have been presented. Also presented are the results of the site selective substitution of Mn by Co in a homometallic Mn based MOF and it’s
subsequent decomposition to CoMn2O4 spinel oxide nanoparticles.
In chapter 3, the syntheses, structures and the magnetic properties of the pentanuclear Mn5 based MOF compounds with SDBA have been presented. The role of the time and the temperature in the formation of the compounds has also been presented.
In chapter 4, the dehydration/rehydration mediated switchable room temperature ferroelectric behavior, the single crystal to single crystal solvent exchange studies and selective gas sorption behavior in an anionic Co based MOF with SDBA has been discussed.
In chapter 5, the use of the liquid-liquid biphasic synthetic route in the
formation of Zn and Cd based MOFs with ABA has been discussed. Structural
transformations between the one dimensional Zn based compounds and the heterogeneous catalytic studies using the Cd based compounds have also been presented.
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Pinela, Sara Cristina Ribeiro Grincho. "Evaluation of nanoporous materials for biotoxin capture." Master's thesis, 2016. http://hdl.handle.net/1822/47331.
Full textAbstract:
Dissertação de mestrado integrado em Engenharia Biológica (área de especialização em Tecnologia do Ambiente)Biotoxins are metabolites produced by some microalgae species that can reach high concentrations when a massive proliferation of them occur. These kind of compounds are especially dangerous when concentrated in digestive glands of seafood. In general, biotoxins do not affect mollusks, however, the presence of biotoxins turns the mollusks unappropriated for human consumption. In this way, it is very important to improve monitoring methods of biotoxins in water in order to generate an early warning system before seafood becomes toxic. This thesis proposes an improvement in Solid Phase Adsorption Toxin Tracking (SPATT) devices for early warning of the presence of biotoxins in water. To do so, instead of using the chromatographic resins commonly used in SPATT devices, a new nanoporous material, Covalent Organic Frameworks (COFs), was evaluated due to their pore uniform size to be similar to the toxins size. Adsorption/desorption tests of the lipophilic toxin okadaic acid (OA) in COFs were performed, at laboratorial scale, as well as tests of the reuse of the adsorbent material. Adsorption kinetics and adsorption isotherm at 19 ºC were determinated. Finally, diffusion of the toxin into the pores was studied. The results showed that COFs could improve SPATT devices performance since they can capture much more quantity of toxin (about 30 times more) that common chromatographic resins and faster due to the fact that toxin diffusion in pores is almost instantaneous. The determined Freundlich isotherm showed a favorable linear tendency. Finally, COFs can be reused, once desorption can be successfully made using solvents, such as 70 % ethanol and acetonitrile.
As biotoxinas são metabolitos produzidos por algumas espécies de microalgas, que podem atingir altas concentrações aquando uma proliferação maciça das mesmas ocorre. Este tipo de compostos é especialmente perigoso quando concentrados nos sistemas digestivos do marisco. Geralmente, as biotoxinas não afetam o marisco, porém, a sua presença torna-o impróprio para consumo humano. Neste sentido, é importante que se melhorem os métodos de monotorização de biotoxinas na água, de maneira a que se possa estabelecer um sistema de alerta antecipado, antes de o marisco se tornar tóxico. Esta dissertação propõe um aperfeiçoamento de dispositivos de Solid Phase Adsorption Toxin Tracking (SPATT), para uma deteção atempada da presença de biotoxinas na água. Para tal, em vez das resinas geralmente usadas nos dispositivos SPATT, foi avaliado um novo material nanoporoso, Covalent Organic Frameworks (COFs), devido à uniformidade do tamanho de poro deste material ser mais semelhante ao tamanho das toxinas. Testes de adsorção/desorção da toxina lipofílica ácido ocadaíco (OA) foram feitos, à escala laboratorial, assim como testes de reuso do material adsorvente. As cinéticas de adsorção e a isotérmica de adsorção a 19 ºC foram determinadas. Por fim, a difusão da toxina nos poros do COF foi outro ponto estudado. Os resultados dos testes laboratoriais realizados mostram que os COFs podem melhorar o desempenho dos dispositivos de SPATT, uma vez que conseguem capturar muito mais quantidade de toxina (cerca de 30 vezes mais) que as resinas geralmente usadas nos dispositivos de SPATT e conseguem fazê-lo muito mais rapidamente, devido ao facto de a difusão da toxina nos poros ser quase instantânea. A isotérmica de Freundlich determinada mostrou ter uma tendência linear favorável. Por fim, o COF pode também ser reutilizado, uma vez que a dessorção de toxina pode ser feita com sucesso, usando solventes orgânicos, como o etanol a 70 % e o acetonitrilo.