Es wurden verschiedene NMR-spektrokopische Messungen an flexiblen und chiralen MOFs durchgeführt. Zur Untersuchung der Porensysteme kamen 129Xe-NMR und 13C-NMR an adsorbiertem CO2 zum Einsatz, während die MOF-Gitter und ihre Wechselwirkungen mit adsorbierten Gastmolekülen mittels 13C- und 1H-MAS-NMR-Spektroskopie studiert wurden. Während DUT-8(Ni) Flexibilität zeigt, weist DUT-8(Cu) ein starres Gitter auf. Die Flexibilität der sogenannten Solid-Solutions hängt in ausgeprägter Weise vom Verhältnis der funktionalisierten bdc-Linker 2,5-bme-bdc und db-bdc ab. Dieses Verhältnis hat zudem einen großen Einfluss auf die Orientierung der adsorbierten CO2-Moleküle. Es wurde erstmals eine Methode vorgestellt, die den Festkörper-NMR-spektroskopischen Nachweis chiraler Seitengruppen in chiralen MOFs erlaubt, wie anhand des chiral modifizierten UMCM-1 (ChirUMCM-1) demonstriert wurde. Die Chiralität kann einen NMR-spektroskopisch messbaren Einfluss auf die intrinsische Dynamik des MOF-Gitters ausüben, wie am chiral modifizierten DUT-32 deutlich wurde, dessen chirale Seitengruppe selektiv 15N- und 13C-isotopenmarkiert wurde.

Synthesis of polycrystalline, vs. single-crystalline porous materials, such as metal-organic frameworks (MOFs), is usually beneficial due to shorter synthetic time and higher yields. However, the structural characterization of these materials by X-ray powder diffraction can be complicated. Even more difficult, is to track structural changes of MOFs by in situ experiments. Hence, we designed several successful techniques for the structural investigation of porous MOFs. These methods utilize the Structure Envelope (SE) density maps. SEs are surfaces which describing the pore system with the framework. It was shown that these maps can be easily generated from the structure factors of a few (1 to 10) of the most intense low index reflections. Application of SE in Charge Flipping calculations shortens and simplifies structure determination of MOF materials. This method provides excellent MOF models which can be used as a good starting point for their refinement. However, the most interesting results have been found by using Difference Envelope Density (DED) analysis. DED plots are made by taking the difference between observed and calculated SE densities. This allows us to study guest related issues of MOFs such as, location of guest molecules in the pores, tracking activation of MOFs and gas loading, etc. We also have shown that, DED created from routine powder diffraction patterns might provide very important information about MOF structure itself. In fact DED can be used for study of interpenetration, substituents locations and effects conformational changes in the MOF ligands. Generation and analysis of SEs and DEDs are easy and straightforward. It provides the information needed to explain major deviations in structure-property relationship in MOFs. In our opinion, this method might become one of the important and routine techniques for MOFs structural analysis.

Submitted by JADER BARBOSA DA SILVA FLOR null (jader@iq.unesp.br) on 2017-05-22T17:08:38Z No. of bitstreams: 1 TESE VERSÃO FINAL para a impressão.pdf: 8986552 bytes, checksum: 9b079a86ffb72f7d5def9d9e6c6ba45e (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-05-23T17:35:16Z (GMT) No. of bitstreams: 1 flor_jbs_dr_araiq.pdf: 8986552 bytes, checksum: 9b079a86ffb72f7d5def9d9e6c6ba45e (MD5) / Made available in DSpace on 2017-05-23T17:35:16Z (GMT). No. of bitstreams: 1 flor_jbs_dr_araiq.pdf: 8986552 bytes, checksum: 9b079a86ffb72f7d5def9d9e6c6ba45e (MD5) Previous issue date: 2017-05-03 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Neste projeto foram sintetizados e caracterizados materiais porosos conhecidos como Metal-Organic Frameworks (MOFs) que abrangem uma área da química que tem experimentado um crescimento muito grande nas duas últimas décadas. MOFs são compostos cristalinos contendo espaços potencialmente vazios (poros) construídos a partir de íons ou clusters metálicos interconectados por espaçadores orgânicos. Além da diversidade estrutural e topológica, estes materiais têm enorme potencial para muitas aplicações. Dentro desse contexto, o objetivo central do trabalho foi a preparação de MOFs de cobre(II) e zinco(II) e investigação da potencialidade de aplicação em catálise heterogênea. Dentre outros materiais, a MOF MOF-INZ foi preparada pela primeira vez a partir da funcionalização da HKUST-1 via processo PSM (Pos-Synthetic Modification) pela coordenação da isoniazida nos centros coordenativamente insaturados (CUSs) do íon cobre(II) do material precursor ativado. A utilização desse material como catalisador em reações de cicloadição de CO2 frente ao epóxido de propileno resultou em 95% de conversão do reagente em carbonato de propileno (após 72 horas, em presença de TBAI). A última etapa do trabalho consistiu na preparação das MOFs ZIF-8 e HKUST-1 em escala nanométrica, usando moduladores de concentração, e no desenvolvimento de uma técnica muito elegante para a formação de filmes finos sobre nanotubos de dióxido de titânio (com diâmetros da ordem de 50-100 nm). Os materiais híbridos preparados foram então submetidos a reações foto- e fotoeletrocatalíticas de redução de CO2. As MOFs adsorvidas nos eletrodos nanoestruturados mostraram atividades significativamente mais altas em comparação com o eletrodo não modificado. Sob irradiação de luz e na presença de ácido ascórbico, o compósito Ti/TiO2-ZIF-8 gerou cerca de 30 mmol/L de etanol e 2 mmol/L de metanol em fase gasosa, enquanto que reações fotoeletrocatalíticas de redução de CO2 produziram 104 mmol/L e 17 mmol/L desses mesmos produtos, respectivamente. Do que seja do nosso conhecimento, essa é a primeira vez que a redução fotoeletrocatalítica desse importante gás causador do efeito estufa é realizada sobre materiais baseado em MOFs e abre uma frente de pesquisa bastante promissora no que tange a introdução dessa importante classe de materiais porosos no design de fotoeletrocatalisadores para reações gasosas. / In this project, porous materials known as Metal-Organic Frameworks (MOFs) were synthesized and characterized, which cover a chemistry area that has experienced a very large growth in the last two decades. MOFs are crystalline compounds containing potentially empty spaces (pores) constructed from ions or metal clusters interconnected by organic spacers. In addition to structural and topological diversity, these materials have enormous potential for many applications. In this context, the main objective of the work was the preparation of copper (II) and zinc (II) MOFs and the investigation of the potentiality of application in heterogeneous catalysis. Among other materials, MOF MOF-INZ was prepared for the first time from the functionalization of HKUST-1 via PSM (Post-Synthetic Modification) process by the coordination of isoniazid to the coordinated unsaturated (CUSs) centers of the copper (II) activated precursor. The use of this material as a catalyst in CO2-cycloaddition reactions to propylene epoxide resulted in 95% conversion of the reactant into propylene carbonate (after 72 hours in the presence of TBAI). The last stage of the work consisted in the preparation of the ZIF-8 and HKUST-1 MOFs at nanoscale using concentration modulators and the development of a very elegant technique for the formation of thin films on titanium dioxide nanotubes (with diameters in the order of 50-100 nm). The prepared hybrid materials were then submitted to photo- and photoelectrocatalytic CO2 reduction reactions. The MOFs adsorbed on the nanostructured electrodes showed significantly higher activities compared to the unmodified electrode. Under light irradiation and in the presence of ascorbic acid, the Ti / TiO2-ZIF-8 composite generated about 30 mmol / L of ethanol and 2 mmol / L of methanol in the gas phase, while photoelectrocatalytic CO2 reduction reactions produced 104 Mmol / L and 17 mmol / L of these same products, respectively. To our knowledge, this is the first time that the photoelectrocatalytic reduction of this important greenhouse gas is carried out on materials based on MOFs and opens a very promising research front regarding the introduction of this important class of porous materials in the design of photoelectrocatalysts for gaseous reactions.

La recherche sur la conception de nouveaux matériaux, dits intelligents, est en constant progrès depuis plus de 30 ans. Historiquement, les premiers matériaux utilisés et transformés par l’homme étaient le bois, les minéraux et ses dérivés (pierre, métaux, etc.). C’est à la fin du 19e siècle que la synthèse des polymères organiques et inorganiques ainsi que leurs utilisations se développèrent. Ce progrès continue de nos jours. Ainsi, c’est dans cette direction que cette thèse fut rédigée, l’étude de polymères de coordination basés sur le cuivre(I). Elle s’orchestra en six principales sections de recherche. La première section, i.e. le chapitre 2 traite de la coordination de différents ligands monothioéthers sur du CuX (X = I, Br) pour former plusieurs types de polymères de coordination (CPs). Ainsi, le CP 1D [(Me[indice inférieur 2]S)[indice inférieur 3]{Cu[indice inférieur 2]([mu]-I)[indice inférieur 2}][indice inférieur n] est obtenu quand CuI et Sme[indice inférieur 2] réagissent ensemble dans le n-heptane, alors qu’ils entrainent la formation du CP 2D [(Me[indice inférieur 2]S) [indice inférieur 3] {Cu[indice inférieur 4]([mu]-I) [indice inférieur 4]}] [indice inférieur n] dans le MeCN. Ce dernier contient des unités de construction secondaire (SBU ; Secondary Building Units en anglais) en forme de cluster Cu[indice inférieur 4]I[indice inférieur 4] « cubane partiellement ouvert ». En faisant réagir le MeSEt avec du CuI, le CP 2D [(MeSEt) [indice inférieur 2]{Cu[indice inférieur 4] ([mu][indice inférieur 3]-I) [indice inférieur 2] ([mu][indice inférieur 2]-I) [indice inférieur 2]}(MeCN) [indice inférieur 2]] [indice inférieur n] contenant des SBUs de type Cu[indice inférieur 4]I[indice inférieur 4] « cubanes en escalier » a été isolé dans MeCN, alors qu’ils entrainent l’obtention du polymère 1D [(MeSEt) [indice inférieur 3]{Cu[indice inférieur 4] ([mu][indice inférieur 3]-I) [indice inférieur 4]}] [indice inférieur n] dans le n-heptane contenant quant à lui des clusters de types Cu[indice inférieur 4]I[indice inférieur 4] « cubanes fermés ». Alors que le traitement de MeSPr avec du CuI forme le CP 1D [(MeSPr) [indice inférieur 3]{Cu[indice inférieur 4] ([mu][indice inférieur 3]-I) [indice inférieur 4]}] [indice inférieur n], les composés [(L) [indice inférieur 4]{Cu[indice inférieur 4] ([mu][indice inférieur 3]-I) [indice inférieur 4]}] (L = EtSPr, Pr[indice inférieur 2]S) sont respectivement obtenus avec le EtSPr et le Pr[indice inférieur 2]S. À partir du [indice supérieur i]Pr[indice inférieur 2]S et de CuI, le cluster [([indice supérieur i]Pr[indice inférieur 2]S) [indice inférieur 6]{Cu[indice inférieur 8] ([mu][indice inférieur 3]-I) [indice inférieur 3]}([mu][indice inférieur 4]-I) [indice inférieur 2]}] est obtenu alors que l’on forme un CP 2D [(Cu[indice inférieur 3]Br[indice inférieur 3])(MeSEt) [indice inférieur 3]] [indice inférieur n] à partir de CuBr et MeSEt dans l’heptane. Ce dernier incorpore à la fois des Cu([mu][indice inférieur 2]-Br) [indice inférieur 2]Cu rhomboédriques et des SBUs de type Cu[indice inférieur 4]Br[indice inférieur 4] « cubanes ouverts ». Le MeSPr forme, quant à lui avec le CuBr dans l’heptane, le CP 1D [(Cu[indice inférieur 3]Br[indice inférieur 3])(MeSPr) [indice inférieur 3]] [indice inférieur n] qui, après recristallisation dans le MeCN, est converti en un CP 2D [(Cu[indice inférieur 5]Br[indice inférieur 5])([mu][indice inférieur 2]-MeSPr) [indice inférieur 3]] [indice inférieur n] incorporant des SBUs [(Cu[indice inférieur 5] ([mu][indice inférieur 4]-Br)([mu][indice inférieur 2]-Br)]. Les propriétés de stabilités thermiques et photophysiques de ces matériaux ont aussi été reportées.   Dans la section 2, i.e. au chapitre 3, les réactions entre des ligands dithioétherbutanes (1,4-bis(phénylthio)butane et 1,4-bis(cyclohexylthio)butane) avec CuX (X = Br, I) ont été étudiées. En faisant réagir les CuX avec le 1,4-bis(cyclohexylthio)butane, dans le ratio (1:1), les CPs 1D, peu luminescents, isostructuraux [(Cu[indice inférieur 2]X[indice inférieur 2])([mu]-CyS(CH[indice inférieur 2]) [indice inférieur 4])SCy) [indice inférieur 2]] [indice inférieur n] (X = Br, I) sont obtenus. Inversement, quand CuI réagit avec 1,4-bis(phénylthio)butane, dans le ratio (2:1), il se forme le préalablement reporté CP 2D [(Cu[indice inférieur 4]I[indice inférieur 4])([mu]- PhS(CH[indice inférieur 2]) [indice inférieur 4])SPh) [indice inférieur 2]] [indice inférieur n], alors qu’avec le CyS(CH[indice inférieur 2]) [indice inférieur 4])SCy, un nouveau composé luminescent est obtenu, mais sa structure n’a pas pu être résolue.(1) Les caractérisations habituelles en photophysique et en stabilité thermique ont été menées sur ces matériaux. Dans la troisième section, i.e. dans le chapitre 4, les réactions de coordination de CuX (Br, I) sur les ligands dithioétherbutènes E- et Z-PhS(CH[indice inférieur 2]CH=CHCH[indice inférieur 2])SPh, E- et Z-pTolS(CH[indice inférieur 2]CH=CHCH[indice inférieur 2])S-pTol ont été comparées. Quand les sels CuX réagissent avec E-PhS(CH[indice inférieur 2]CH=CHCH[indice inférieur 2])SPh les CP 2D [Cu[indice inférieur 2]X[indice inférieur 2]{[mu]-E-PhS(CH[indice inférieur 2]CH=CHCH[indice inférieur 2])SPh}[indice inférieur 2]] [indice inférieur n] (X = I, Br), composés isostructuraux, sont obtenus. Incorporant une structure sans-précédente, ces réseaux sont formés à partir de couches 2D en alternance ABAB, contenants des SBUs Cu[indice inférieur 2] ([mu][indice inférieur 2]-X) [indice inférieur 2] rhomboédriques. Inversement, quand l’isomère Z-PhS(CH[indice inférieur 2]CH=CHCH[indice inférieur 2])SPh réagit avec des sels de CuX, deux structures différentes sont obtenues : le CP 2D [Cu[indice inférieur 4] ([mu][indice inférieur 3]-I) [indice inférieur 4] ([mu]-Z-PhS(CH[indice inférieur 2]CH=CHCH[indice inférieur 2])SPh}[indice inférieur 2]] [indice inférieur n] contenant des SBUs de type « cubane fermé » et le complexe 0D [Cu[indice inférieur 2]Br[indice inférieur 2]{[mu]-Z-PhS(CH[indice inférieur 2]CH=CHCH[indice inférieur 2])SPh}[indice inférieur 2]]. De par la réaction de E-pTolS(CH[indice inférieur 2]CH=CHCH[indice inférieur 2])S-pTol avec CuI, le CP 2D [{Cu([mu][indice inférieur 3]-I)} [indice inférieur 2] ([mu]-E-pTolS(CH[indice inférieur 2]CH=CHCH[indice inférieur 2])S-pTol)]n contenant des rubans parallèles en escalier est obtenu, alors que la structure issue de CuBr n’a pas pu être résolue. Finalement, quand CuX réagit avec Z-pTolS(CH[indice inférieur 2]CH=CHCH[indice inférieur 2])S-pTol, les CPs 2D iso-structuraux [Cu[indice inférieur 2]X[indice inférieur 2]{[mu]-Z-pTolS(CH[indice inférieur 2]CH=CHCH[indice inférieur 2])S-pTol}[indice inférieur 2]] (X = I, Br) sont formés. Dans ce cas, contrairement, aux premières structures obtenues, les couches de ces CPs sont composées de grilles incorporant des SBUs rhomboédriques Cu[indice inférieur 2] ([mu][indice inférieur 2]-X) [indice inférieur 2] dont les distances Cu···Cu sont identiques d’une couche à l’autre. Les caractérisations habituelles en photophysique et en stabilités thermiques ont été menées sur ces matériaux. De plus, des calculs théoriques ont été réalisés afin de mieux comprendre les propriétés photophysiques de ces composés. La quatrième section, i.e. le chapitre 5, traite des réactions de CuX (Br, I, Cl) sur des ligands dithioétherbutynes (1,4-bis(pTolthio)but-2-yne et 1,4-bis(benzylthio)but-2-yne. Quand CuBr réagit avec 1,4-bis(pTolthio)but-2-yne, le CP 1D [{Cu([mu][indice inférieur 2]-Br) [indice inférieur 2]Cu}([mu]-pTolSCH[indice inférieur 2]C≡CCH[indice inférieur 2]S-pTol) [indice inférieur 2]] [indice inférieur n] est obtenu, alors que le CP 2D [{Cu[indice inférieur 4] ([mu][indice inférieur 3]-I) [indice inférieur 4]}([mu]-pTolSCH[indice inférieur 2]C≡CCH[indice inférieur 2]S-pTol) [indice inférieur 2]] [indice inférieur n], préalablement reporté, est formé.(2) La réaction des sels CuI et CuCl avec 1,4-bis(benzylthio)but-2-yne engendre la formation de complexes isomorphes 0D [{Cu([mu][indice inférieur 2]-X) [indice inférieur 2]Cu}([mu]-PhCH[indice inférieur 2]SCH[indice inférieur 2]C≡CCH[indice inférieur 2]SCH[indice inférieur 2]Ph) [indice inférieur 2]] (X = I, Br). Contrairement à l’utilisation de CuCl, qui avec PhCH[indice inférieur 2]SCH[indice inférieur 2]C≡CCH[indice inférieur 2]SCH[indice inférieur 2]Ph forme le CP 2D [{Cu[indice inférieur 2] ([mu][indice inférieur 2]-Cl)([mu] [indice inférieur 3]-Cl)}([mu]-PhCH[indice inférieur 2]SCH[indice inférieur 2]C≡CCH[indice inférieur 2]SCH[indice inférieur 2]Ph)] [indice inférieur n]. Notons que ce CP présente des propriétés de photophysique peu communes pour un dérivé chloré, car il émet de la lumière autour de 600 nm. La cinquième section, i.e. le chapitre 6, traite des réactions de CuI avec PhS(CH[indice inférieur 2]) [indice inférieur 8]SPh et pTolS(CH[indice inférieur 2]) [indice inférieur 8]S-pTol qui génèrent respectivement les CPs luminescents 1D [Cu[indice inférieur 4]I[indice inférieur 4]{[mu][indice inférieur 2]-PhS(CH[indice inférieur 2]) [indice inférieur 8]SPh}[indice inférieur 2]] [indice inférieur n] et 2D [Cu8I8{[mu]2-pTolS(CH2)8S-pTol}3(MeCN)2]n. Le CP 2D [Cu8I8{[mu]2-pTolS(CH2)8S-pTol}3 (MeCN)2]n présente un réseau qui n’avait jamais été rencontré dans la littérature auparavant, c.-à-d., des couches de polymère construites à partir de deux cubanes fermés pontés ensemble par un rhomboèdre comme SBUs. Leurs propriétés physiques et de stabilités thermiques ont été étudiées et présentent quelques différences notables. La sixième section, i.e. le chapitre 7, traite des réactions entre CuI avec le ligand flexible pTolS(CH[indice inférieur 2]) [indice inférieur 8]S-pTol dans le MeCN ou EtCN et p-[indice supérieur t]BuC[indice inférieur 6]H[indice inférieur 4]S(CH[indice inférieur 2]) [indice inférieur 8]SC[indice inférieur 6]H[indice inférieur 4]-p-[indice supérieur t]Bu L2 dans EtCN. Les synthèses issues de pTolS(CH[indice inférieur 2]) [indice inférieur 8]S-pTol permettent l’obtention de CPs 2D [Cu[indice inférieur 8]I[indice inférieur 8]{pTolS(CH[indice inférieur 2]) [indice inférieur 8]S-pTol}[indice inférieur 3] (solvant) [indice inférieur 2]] [indice inférieur n] (1•MeCN et 1•EtCN) contenant des nœuds de connexion de type Cu[indice inférieur 8]I[indice inférieur 8]. Par opposition, l’utilisation du ligand p-[indice supérieur t]BuC[indice inférieur 6]H[indice inférieur 4]S(CH[indice inférieur 2]) [indice inférieur 8]SC[indice inférieur 6]H[indice inférieur 4]-p-[indice supérieur t]Bu dans EtCN entraine la formation d’un CP 1D [Cu[indice inférieur 4]I[indice inférieur 4]{p-[indice supérieur t]BuC[indice inférieur 6]H[indice inférieur 4]S(CH[indice inférieur 2]) [indice inférieur 8]SC[indice inférieur 6]H[indice inférieur 4]-p-[indice supérieur t]Bu}[indice inférieur 2] (EtCN) [indice inférieur 2]] [indice inférieur n] incorporant les SBUs de type cubane fermé. Les CPs 2D 1•MeCN et 1•EtCN, contrairement à 2•EtCN, présentent l’habilité de pouvoir perdre le solvant initialement incorporé dans leur structure sous vide et de le readsorber ou d’adsorber un autre solvant, chose qui peut être suivie à l’aide de la variation de la luminescence, la stabilité thermique, ou encore par diffraction des rayons X sur poudre. La septième section, i.e. le chapitre 8 traite des réactions, une fois encore, entre un ligand dithioéther, contenant un pont flexible butane (EtS(CH[indice inférieur 2]) [indice inférieur 4]SEt) et les sels CuX (X = I, Br). Dans ce cas, il se forme avec le CuI un CP luminescent 2D [Cu[indice inférieur 4]I[indice inférieur 4]{[mu]-EtS(CH[indice inférieur 2]) [indice inférieur 4]SEt}[indice inférieur 2]] [indice inférieur n], alors qu’il génère avec CuBr, le CP 3D [(Cu[indice inférieur 2]Br[indice inférieur 2]){[mu]-EtS(CH[indice inférieur 2]) [indice inférieur 4]SEt}][indice inférieur n] faiblement luminescent, construit sur des couches en parallèle pontées par les soufres doublement n-donneurs. Il est intéressant de remarquer qu’une migration de l’énergie d’excitation se produit dans le CP 3D (dérivé bromé) contrairement au CP 2D (dérivé iodé) sous excitation de haute intensité. Très peu d’exemples présentent ce type de processus parmi tous les CPs ( < 10). Pour conclure, les réactions entre les sels CuX (X = Cl, Br, I) avec des ligands thioéthers de types différents (mono-, di-thio, rigide ou flexible) peuvent offrir des matériaux de structures variables (CP 0D, 1D, 2D, 3D avec et sans cavités) présentant leurs propres spécificités (luminescence, stabilité thermique, adsorption de gaz, solvatochromisme, etc.). Le résultat le plus important à noter, en comparaison avec la littérature est, qu’il est très difficile, voire impossible, de pouvoir prédire la dimensionnalité, la structure et les propriétés dont résultera la coordination des ligands thioéthers sur des sels de CuX (X = Cl, Br, I). Par conséquent, de nombreuses combinaisons et études restent encore à être menées pour mieux comprendre ces matériaux et trouver la, ou les meilleures combinaisons possibles pour concevoir des MOFs luminescents à partir de CuX.

This thesis presents the synthesis, properties, and applications of two important classes of metal-organic frameworks (MOFs); lanthanide MOFs and hierarchical porous zeolitic imidazolate frameworks (ZIFs). The materials have been characterized using a wide range of techniques including diffraction, imaging, various spectroscopic techniques, gas sorption, dynamical light scattering (DLS) and thermogravimetric analysis (TGA). In Chapter 1, the unique features of MOFs and ZIFs as well as their potential applications are summarized. In Chapter 2, different characterization techniques are presented. Chapter 3 describes a family of new isoreticular lanthanide MOFs synthesized using tri-topic linkers of different sizes, H3L1-H3L4, denoted SUMOF-7I-IV (Ln) (SU; Stockholm University, Ln = La, Ce, Pr, Nd, Sm, Eu and Gd, Paper I). The SUMOF-7I-III (Ln) contain permanent pores and exhibit exceptionally high thermal and chemical stability. The luminescence properties of SUMOF-7IIs are reported (Paper II). The influences of Ln ions and the tri-topic linkers as well as solvent molecules on the luminescence properties are investigated. Furthermore, the potential of SUMOF-7II (La) for selective sensing of Fe (III) ions and the amino acid tryptophan is demonstrated (Paper III).  Chapter 4 presents a simple, fast and scalable approach for the synthesis of hierarchical porous zeolitic imidazolate framework ZIF-8 and ZIF-67 using triethylamine (TEA)-assisted approach (Paper IV). Organic dye molecules and proteins are encapsulated directly into the ZIFs using the one-pot method. The photophysical properties of the dyes are improved through the encapsulation into ZIF-8 nanoparticles (Paper IV). The porosity and surface area of the ZIF materials can be tuned using the different amounts of dye or TEA. To further simplify the synthesis of hierarchical porous ZIF-8, a template-free approach is presented using sodium hydroxide, which at low concentrations induces the formation of zinc hydroxide nitrate nanosheets that serve as in situ sacrificial templates (Chapter 5, Paper V). A 2D leaf-like ZIF (ZIF-L) is also obtained using the method. The hierarchical porous ZIF-8 and ZIF-L show good performance for CO2 sorption. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 5: Manuscript.</p>

This work explores the use of computational methods to aid in the design of Metal Organic Frameworks (MOFs) for use as CO2 scrubbers in carbon capture and storage applications. One of the main challenges in this field is in identifying important MOF design characteristics which optimize the complex interactions governing surface adsorption. We approach this in a high-throughput manner, determining properties important to CO2 adsorption from generating and sampling a large materials search space. The utilization of MOFs as potential carbon scrubbing agents is a recent phenomenon, as such, many of the computational tools necessary to perform high-throughput screening of MOFs and subsequent analysis are either underdeveloped or non-existent. A large portion of this work therefore involved the development of novel tools designed specifically for this task. The chapters in this work are contiguous with the goal of designing MOFs for CO¬2 capture, and somewhat chronological in order and complexity, meaning as time and expertise progressed, more advanced tools were developed and utilized for the purposes of computational MOF discovery. Initial work towards MOF design involved the detailed analysis of two experimental structures; CALF-15 and CALF-16 using classical molecular dynamics, grand canonical Monte Carlo simulations, and DFT to determine the structural features which promote CO2 adsorption. An unprecedented level of agreement was found between theory and experiment, as we are able to capture, with simulation, the X-ray resolved binding sites of CO2 in the confined pores of CALF-15. Molecular simulation was then used to provide a detailed breakdown of the energy contributions from nearby functional groups in both CALF-15 and CALF-16. A large database of hypothetical MOF structures is constructed for the purposes of screening for CO2 adsorption. The database contains 1.3 million hypothetical structures, generated with an algorithm which snaps together rigid molecular building blocks extracted from existing MOF crystal structures. The algorithm for constructing the hypothetical MOFs and the building blocks themselves were all developed in-house to form the resulting database. The topological, chemical, and physical features of these MOFs are compared to recently developed materials databases to demonstrate the larger structural and chemical space sampled by our database. In order to rapidly and accurately describe the electrostatic interactions of CO2 in the hypothetical database of MOFs, parameters were developed for use with the charge equilibration method. This method assigns partial charges on the framework atoms based on a set of parameters assigned to each atom type. An evolutionary algorithm was used to optimize the charge equilibration parameters on a set of 543 hypothetical MOFs such that the partial charges generated would reproduce each MOFs DFT-derived electrostatic potential. Validation of these parameters was performed by comparing the CO2 adsorption from the charge equilibration method vs DFT-derived charges on a separate set of 693 MOFs. Our parameter set were found to reproduce DFT-derived CO2 adsorption extremely well using only a fraction of the time, making this method ideal for rapid and accurate high-throughput MOF screening. A database of 325,000 MOFs was then screened for CO2 capture and storage applications. From this study we identify important binding pockets for CO2 in MOFs using a binding site analysis tool. This tool uses a pattern recognition method to compare the 3-D configurations of thousands of pore structures surrounding strong CO2 adsorption sites, and present common features found amongst them. For the purposes of developing larger databases which sample a more diverse materials space, a novel MOF construction tool is devloped which builds MOFs based on abstract graphs. The graph theoretical foundations of this method are discussed and several examples of MOF construction are presented to demonstrate its use. Notably, not only can it build existing MOFs with complicated geometries, but it can sample a wide range of unique structures not yet discovered by experimental means.

Reducing anthropogenic carbon dioxide emissions from coal-fired power plants is an important step in mitigating climate change. To implement carbon dioxide capture technologies, materials capable of removing carbon dioxide efficiently are required. Currently, liquid amine technology is used for carbon dioxide capture. However, the mechanism for carbon dioxide removal in liquid amine requires extraordinary amounts of energy input. Alternatively, solid sorbents such as metal-organic frameworks (MOFs) show promising potentials as a type of material for carbon dioxide capture. Due their varying structural properties, MOFs can be configured for specific purposes. Certain MOFs carry a net charge on their frameworks, which may allow for increased interactions with carbon dioxide molecules. In this work, charged MOFs were studied for their potential in carbon dioxide capture. Due to the massive number of MOFs available, computational methods were employed for the study. This project includes three major components: (1) the development of novel computational methods to simulate the gas adsorption properties in charged materials, (2) a diverse database of 47,244 hypothetical charged MOFs was constructed to represent the capabilities of charged MOFs, and (3) screening of high performing charged MOFs for carbon capture application by combining the previous two portions of the project. The methods developed in this work include fitting intermolecular interaction parameters to quantum mechanical calculations in periodic systems with net charges. No methods have been reported in literature for such parameter fittings, even in well studied materials such as zeolites. Therefore, the gas adsorption estimation method for charged materials developed in this work is proprietary. Also, databases of hypothetical MOFs with framework net charges have never been reported previously in literature. By screening the charged MOFs in the database with the methods developed, gas adsorption capabilities were evaluated. The adsorption properties of a neutral group of hypothetical MOFs were also obtained for a baseline comparison. Between the two groups of MOFs, charged MOFs were found to outperform neutral MOFs in three key aspects. Firstly, charged MOFs were able to adsorb an average of three times as much carbon dioxide than the neutral group. Secondly, charged MOFs were capable of removing twice the amount of carbon dioxide per adsorption/desorption cycle than the neutral MOFs. Lastly, charged MOFs were able to selectively adsorb much more carbon dioxide over other gasses present in the carbon dioxide capture situations. Specific structural features that resulted in the selectiveness of adsorption in charged MOFs were identified. Also, positive correlations were found between the adsorption of carbon dioxide and the charge present in the MOFs. As seen in the results, charges present in MOFs can greatly increase their ability to remove carbon dioxide. Charged MOFs in the hypothetical database not only outperformed neutral MOFs, certain top performers were also found to exceed the requirements for post-combustion carbon capture application. Therefore, charged MOFs were shown to be a possible material for future carbon dioxide capture. The proprietary methods developed in this work can not only be used to simulate gas adsorptions in charged MOFs, but also for other porous materials, regardless of net charges presented in their systems. Also, the database constructed in this work can be utilized in multiple ways. Aside from carbon dioxide capture capabilities, the charged MOFs in the database can be screened for other gas separations and catalysis via high throughput screening. The database and the computational methods developed in this work pave the way for discovering the capabilities of charged materials.

The crystal growth of nanoporous materials is different from most other classes of material in that their framework architectures contain periodic arrangement of pores or voids in which there is no direct bonding between adjacent units of the framework. This poses a variety of questions as to how such parts of framework develop during the crystallization process, atomistically and energetically. Here we use the nanoporous metal-organic framework, ZIF-8 as a prototypical material to obtain a basic understanding of the growth of a nanoporous material. The crystals of ZIF-8 produced in the N,N-dimethylformamide solvent [ZIF-8(DMF)] and methanol-co-N,N-dimethylformamide solvent [ZIF-8(MeOH)] are both rhombic dodecahedron in shape with a much smaller crystal size in the latter. In the study of the kinetics of ZIF-8(DMF) crystallization, we get a good agreement in the values of activation energies using both Avrami-Erofe’ev-Hancock-Sharp and Gualtieri’s models, i.e. about 120 kJ mol-1 for nucleation, and 95 kJ mol-1 for crystal growth process. The study of kinetics of ZIF-8 surface growth, by in situ AFM, with ZIF-8(DMF) as seed crystal that are grown in the methanolic growth solution we see faster rate in the <100> directions than the <110> directions, with the most probable activation energy of about 80 kJ mol-1 in both directions. This is the first example of in situ AFM being used to obtain activation energy for a surface growth in MOF. We also reveal here that growth process of ZIF-8 occurs through the nucleation and spreading of successive metastable unenclosed sub-steps to eventually form stable terrace steps of the enclosed framework structure in which this process is reliant on the presence of nonframework species to connect the framework species that have voids between them. The experiments also enable identification of some of the fundamental units in the growth process and the stable crystal surface plane. Further, the spreading of terraces at high supersaturation condition (early state) is fairly isotropic as is seen through the formation of almost-rounded terraces on the surface of ZIF-8. The growth direction becomes clear as the supersaturation condition nears to equilibrium (later stage) by the formation of rhombohedral terraces with pointy ends growing along the <100>, and <110> directions and straight edges growing perpendicular to the <111> direction. Formation of this rhombohedral morphology is explained by a coarse grain approach similar to that used in the Kossel model by making assumptions that the sodalite cage is the growth unit and attachment of one sodalite cage in each growth direction is the rate determining step for the formation of a new row of sodalite cages in each direction. Finally, based on the profiles of growth spirals formed from screw dislocations on the ZIF-8 surface obtained from the ex situ AFM images and ICE theory, plausible screw dislocations with Burgers’ vector of 1/2 <111> and <100>, but not <110>, are deduced. Some of the findings in this work will be applicable to numerous nanoporous materials, and the work in general will support efforts to synthesize and design new framework materials and to control the crystal properties of these materials.

The metal-organic material (MOFs) are considered promising as catalysts in the gas storage and processing and, more recently, as a stationary phases for pre-concentration of analytes on the basis of some properties such as the ability to incorporate a variety of chemical species, thermal stability, surface area and pore volume adjustable. In this study, the MOFs were synthesized according to the hydrothermal synthesis method for 72 hours at a temperature of 180°C. The MOFs heteronuclear of Nd3+ ions containing with 10%, 50% and 90% of Eu3+ ions with the organic ligand pyridine-2,6-dicarboxylic acid (H2DPA) was characterized by elemental analysis, infrared spectroscopy, thermal analysis, calorimetric analysis, spectroscopy luminescence, X-ray crystallography, scanning electron microscopy and N2 adsorption-desorption. Analyses indicated that there was formation of new MOFs whose structural formula suggested by the data of elemental analysis and X-ray crystallography was [(Nd1-xEux)2(DPA)3(H2O)3].H2O (x = 0,1; 0,5 and 0,9). The infrared spectroscopy collaborated with the indication that there was coordination of the metal with the ligand H2DPA because the displacement of the bands observed in the ligand MOFs spectra. The luminescence study showed transitions characteristics of Eu3+ ions and Nd3+ ions in the visible region and infrared, respectively, and the system power transfer mechanisms. According to the N2 adsorption-desorption data the MOFs formed a three-dimensional microporous structure and data channels X-ray crystallography indicated that the crystallization occurred in the monoclinic system with space group P21/c. The MOFs were tested as sorbent in the extraction of pesticides in chicken eggs matrix quantified by gas chromatography-mass spectroscopy (GC-MS) and soursop matrix quantified by high performance liquid chromatography (HPLC) method described by Navickiene, enabling satisfactory recoveries compared to the commercial adsorbent Florisil®. / Os materiais metal-orgânicos (MOFs) são considerados promissores como catalisadores, na estocagem e processamento de gás, e, recentemente, como fase estacionária para pré-concentração de analitos em função de algumas propriedades como: capacidade de incorporar uma variedade de espécies químicas, estabilidade térmica, área superficial e volume de poros ajustáveis. Neste trabalho, MOFs foram sintetizados segundo o método de síntese hidrotermal durante 72 horas em uma temperatura de 180°C. Os MOFs heteronucleares de íons Nd3+ contendo 10%, 50% e 90% de íons Eu3+ tendo como ligante orgânico o ácido piridina-2,6-dicarboxílico (H2DPA) foram caracterizados por análise elementar, espectroscopia de infravermelho, análise térmica, análise calorimétrica, espectroscopia de luminescência, cristalografia de raios-X, microscopia eletrônica de varredura e adsorção-dessorção de nitrogênio. As análises indicaram que houve a formação de novos MOFs, cuja fórmula estrutural sugerida pelos dados da análise elementar e cristalografia de raios-X foi [(Nd1-xEux)2(DPA)3(H2O)3].H2O (x = 0,1; 0,5 e 0,9). A espectroscopia do infravermelho colaborou com a indicação de que houve coordenação dos metais com o ligante H2DPA devido ao deslocamento observado das bandas do ligante nos espectros dos MOFs. O estudo de luminescência mostrou as transições características dos íons Eu3+ e Nd3+ na região do visível e infravermelho, respectivamente bem como os mecanismos de transferência de energia do sistema. De acordo com os dados de adsorção-dessorção de N2 os MOFs formaram uma estrutura tridimensional com canais microporosos e os dados de cristalografia de raios-X indicaram que a cristalização ocorreu em sistema monoclínico com grupo espacial P21/c. Os MOFs foram testados como sorvente na extração de pesticidas na matriz de ovos de galinha quantificado por cromatografia gasosa acoplada a espectroscopia de massas (CG-MS) e na matriz de graviola quantificado por cromatografia líquida de alta eficiência (CLAE) método descrito por Navickiene, possibilitando recuperações satisfatórias quando comparados ao adsorvente comercial Florisil®.

Gaining control over the assembly of crystalline solid-state materials has been significantly advanced through the field of reticular chemistry and metal organic frameworks (MOFs). MOFs have emerged as a unique modular class of porous materials amenable to a rational design with targeted properties for given applications. Several design approaches have been deployed to construct targeted functional MOFs, where desired structural and geometrical attributes are incorporated in preselected building units prior to the assembly process. This dissertation illustrates the merit of the molecular building block approach (MBB) for the rational construction and discovery of stable and highly porous MOFs, and their exploration as potential gas storage medium for sustainable and clean energy applications. Specifically, emphasis was placed on gaining insights into the structure-property relationships that impact the methane (CH4) storage in MOFs and its subsequent delivery. The foreseen gained understanding is essential for the design of new adsorbent materials or adjusting existing MOF platforms to encompass the desired features that subsequently afford meeting the challenging targets for methane storage in mobile and stationary applications.In this context, we report the successful use of the MBB approach for the design and deliberate construction of a series of novel isoreticular, highly porous and stable, aluminum based MOFs with the square-octahedral (soc) underlying net topology. From this platform, Al-soc-MOF-1, with more than 6000 m2/g apparent Langmuir specific surface area, exhibits outstanding gravimetric CH4 uptake (total and working capacities). It is shown experimentally, for the first time, that the Al-soc-MOF platform can address the U.S. Department of Energy (DOE) challenging gravimetric and volumetric targets for the CH4 working capacity for on-board CH4 storage. Furthermore, Al-soc-MOF-1 exhibits the highest total gravimetric and volumetric uptake for carbon dioxide and the utmost total and deliverable uptake for oxygen at relatively high pressures among all microporous MOFs. Additionally, the research studies presented in this dissertation highlight the latest discoveries on our continuous quest for highly-connected nets. Specifically, we report the discovery of two fascinating and highly-connected minimal edge-transitive nets in MOF chemistry, namely pek and aea topologies, via a systematic exploration of rare earth metal salts in combination with relatively less symmetrical 3-connected tricarboxylate ligands. Adsorption studies revealed that pek-MOF-1 offers excellent volumetric CO2 and CH4 uptakes at high pressures.