Submitted by Pedro Barros (pedro.silvabarros@ufpe.br) on 2018-07-19T22:53:08Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) TESE Guilherme de Coimbra Santos.pdf: 6601677 bytes, checksum: 98f83ae5c0517751b976e593f82b4003 (MD5) / Approved for entry into archive by Alice Araujo (alice.caraujo@ufpe.br) on 2018-07-20T21:39:55Z (GMT) No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) TESE Guilherme de Coimbra Santos.pdf: 6601677 bytes, checksum: 98f83ae5c0517751b976e593f82b4003 (MD5) / Made available in DSpace on 2018-07-20T21:39:55Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) TESE Guilherme de Coimbra Santos.pdf: 6601677 bytes, checksum: 98f83ae5c0517751b976e593f82b4003 (MD5) Previous issue date: 2017-02-15 / CNPQ / Este trabalho apresenta a síntese da já conhecida MOF [Zn2(BDC)2(dpNDI)]n (BDC = 1,4-benzenodicarboxilato, dpNDI = N’N’-di(4-piridil)-1,4,5,8-naftalenodiimida), mas, agora dopada em diferentes percentagens (0,1%, 0,5%, 1%, 2% e 5%) com o íon európio (íon sonda), por via solvotermica. Após suas caracterizações, observam-se respostas espectroscópicas, frente à monoaromático, favoráveis na identificação de moléculas hóspedes. A síntese e caracterização de redes de coordenação cristalinas, bem como de compósitos a base de carvão ativado, a partir de íons lantanídeos (Pr³⁺, Nd³⁺, Sm³⁺, Eu³⁺, Gd³⁺, Dy³⁺, Er³⁺, Tm³⁺ e o Yb³⁺) com emprego do ligante flexível, succinato, utilizando-se a técnica hidrotermal para obtenção desses sistemas, foram realizadas, além de investigações de sistemas mixmetal nessa mesma matriz carbonácea. Novos compósitos porosos LnBDC@CA (CA = Carvão ativado, Ln = Pr³⁺; Nd³⁺; Sm³⁺; Eu³⁺; Gd³⁺; Er³⁺; Tm³⁺ e Yb³⁺ e BDC = 1,4benzenodicaboxilato) e CB[6]@CA (CB[6] = Cucurbit[6]uril) foram obtidos utilizando via hidrotermal. O LnBDC e o CB[6] estão localizados dentro dos poros do carvão, como foi observado em análise MEV-EDS, Raio X de pó e IV. A análise de porosimetria mostrou valores tipicamente entre o material CA e LnBDC, com tamanho de poro e área de superfície, respectivamente, 29,56 Å e 353,98 m²g⁻¹ para LnBDC@CA e 35,53 Å e 353,98 m²g⁻¹ para CB[6]@CA. Ambos os materiais mostraram boa capacidade de adsorção para o alaranjado de metila (MO) e o azul de metileno (MB) com seletividade em função do pH. Em meio ácido, ambos os materiais apresentam seletividade por MB e em pH alcalino para o MO, com desempenho perceptível para o CB[6]@CA. Adicionalmente, a luminescência do európio foi utilizada como sonda estrutural para investigar o ambiente de coordenação do íon Eu³⁺ no compósito EuBDC@CA após experimentos de adsorção. / This work presents the synthesis Already known of MOF [Zn2(BDC)2(dpNDI)] (BDC = 1,4-benzenedicarboxylate, dpNDI = N'N'-di (4-pyridyl) -1,4,5,8 - naphthalenediimide), but now doped in different percentages (0.1%, 0.5%, 1%, 2% and 5%) with the europium ion (probe ion) by Solvothermal synthesis. After their characterizations, spectroscopic responses are observed, in touch to monoaromatic, favorable in the identification of guest molecules. The synthesis and characterization of crystalline coordination networks, as well as activated carbon based composites, from lanthanide ions (Pr³⁺, Nd³⁺, Sm³⁺, Eu³⁺, Gd³⁺, Dy³⁺, Er³⁺, Tm³⁺ e o Yb³⁺) with the use of flexible ligands, succinate, using the hydrothermal technique to obtain these systems, were performed, in addition to investigations of mixmetal systems in this same carbonaceous matrix. New porous composites LnBDC@AC (AC= Activated carbon, Ln= Pr3+; Nd³⁺; Sm³⁺; Eu³⁺; Gd³⁺; Er³⁺; Tm³⁺ e Yb³⁺ and BDC= 1,4benzenedicaboxylate) and CB[6]@AC (CB[6]= Cucurbit[6]uril) were obtained using hydrothermal route. The LnBDC and CB[B] are located inside the pore of the carbon materials as was observed in SEM-EDS, XRPD and FT-IR analysis. Porosimetry analysis showed values typically between AC and LnBDC material, with pore size and surface area, respectively, 29,56 Å and 353.98 m2g-1 for LnBDC@AC and 35,53 Å and 353.98 m²g⁻¹ for CB[6]@AC. Both materials showed good absorptive capacity of metil orange (MO) and methylene blue (MB) with selectivity as a function of pH. In acid medium, both materials present selectivity by MB and alkaline pH for MO, with notable performance for CB[6]@AC. Additionally, europium luminescence was used as structural probe to investigate the coordination environment of Eu³⁺ ions in the EuBDC@AC composite after adsorption experiment.

In this thesis computational chemistry has been used to accelerate experimental discovery in the fields of ice recrystallization inhibitors for cryopreservation and ultra-microporous MOFs for carbon dioxide capture and storage. Ice recrystallization is one of the leading contributors to cell damage and death during the freezing process. This occurs when larger ice crystal grains grow at the expense of smaller ones. Naturally occurring biological antifreeze molecules have been discovered but only operate up to -4oC and actually exasperate the problem at temperatures lower than this. Recently, the group of Dr. Robert Ben have been successful in synthesizing small organic molecules which are capable of inhibiting the growth of ice crystals during the freezing process. They have built a library of diverse compounds with varying functionalities and activity. Chemical intuition has been unsuccessful in finding a discernible trend with which to predict activity. Herein we present work where we have utilized a quantitative structure activity relationship (QSAR) model to predict whether a molecule is active or inactive. This was built from a database of 124 structures and was found to have a positive find rate of 82%. Proposed molecules that had yet to be synthesized were predicted to active or inactive using our method and 9/11 structures were indeed active which is strikingly consistent to the 82% find rate. Our efforts to aid in the discovery of these novel molecules will be described here. Metal organic frameworks (MOFs) are a relatively new class of porous materials which have taken the academic community by storm. These three-dimensional crystalline materials are built from a metal node and an organic linker. Depending on the metals and organic linkers used, MOFs can possess a vast range of topologies and properties that can be exploited for specific applications. Ultra-microporous MOFs possess relatively small pores in the range of 3.5 Å to 6 Å in diameter. These MOFs have some structural advantages compared to larger pored MOFs such as molecular sieving, smaller pores which promote strong framework-gas interactions and cooperative effects between guests, and longer shelf-life due to small void volumes and rigid frameworks. Here we present newly synthesized ultra-microporous MOFs based on isonicotnic acid as the organic linker with Ni and Mg as the metal centre. Despite having such small pores, Ni-4PyC exhibits exceptionally high CO2 uptake at high pressures. Furthermore, Mg-4PyC exhibits novel pressure dependent gate-opening behaviour. Computational simulations were employed to investigate the origin of high CO2 uptake, predict high pressure (>10bar) isotherms, quantify CO2 binding site positions and energies, and study uptake-dependent linker dynamics. This work hopes to provide experimentalists with some explanation to these interesting unexplained phenomena and also predict optimal properties for new applications.

This thesis will describe the magnetic behavior found in a scaling array of magnetic nanomaterials that have been uniquely designed, synthesized and characterised in order to better understand their properties with regards to potential future applications. Within Chapter 1 will be a detailed, yet accessible, introduction to nanomagnetism and the fundamental principles and practical techniques essential to the study of this unique mélange of physics and chemistry. This chapter will be designed to give the reader the necessary tools to understand key literature concepts found in Chapter 2, as well as the work presented in the following chapters. Chapter 2 will provide an overview of relevant literature in the field of magnetic nanomaterials, including: nanoparticles, single-molecule magnets, single-chain magnets and metal-organic frameworks. Chapter 3 will describe work performed on nanoparticles doped with lanthanide ions in order to explore their resulting size, shape, crystallinity and magnetic properties. The relevance of the chosen particles (NaYF4) pertains to their proposed use in a variety of applications due to their known luminescent properties, which we sought to hybridize with interesting magnetic properties, thus creating multimodal imaging capabilities. Doping with a variety of desired ratios of lanthanide ions (GdIII, TbIII, DyIII, ErIII and YbIII) was successful, producing crystalline nanoparticles with tunable size and shape. Magnetic measurements displayed a clear absence of superparamagnetic behavior, indicating that these materials have the potential to be well-suited to applications in biomedicine as multimodal imaging probes and MRI contrast agents. Chapter 4 will build on the previously explored doped nanomaterials through creating a hybrid nanomaterial by tethering lanthanide-based magnetic molecules to the surface of nanoparticles. This is performed through the synthetic design of a SMM with two anisotropic DyIII ions, which was synthesized and designed to bear terminal S-groups in order to promote the binding of the magnetic molecule to capping agent free gold nanoparticles. Upon confirmation of the successful surface attachment of the molecules, magnetic measurements displayed that the magnetic molecules maintained their static properties, however, their dynamic properties were altered. This system was the first example of this type of novel approach to the study of magnetic molecules on surfaces for data storage, spintronics, and quantum computing applications. Chapter 5 will expand on the previous study of ordering arrays of magnetic molecules on the surface of nanoparticles by tethering them into 1D chain networks. We successfully synthesized chain networks with YIII, EuIII, GdIII, TbIII and DyIII lanthanide ions. Magnetic characterisation revealed slow relaxation of the magnetization with no significant interactions between magnetic ions, thus these are discrete magnetic molecules in 1D. Rather surprisingly, the isotropic GdIII analogue displayed field induced slow relaxation of the magnetisation, necessitating the use of ab initio calculations in order to shed light on the potential causes of this unexpected behavior. Overall, through the formation and study of these structures, we observed a new potential method of SMM assembly for the study of ordered arrays of molecular magnets. Chapter 6 will focus on ordering of discrete magnetic systems in 3D. With this in mind, we successfully isolated the first Co8 cuboctahedron MOF. Magnetic measurements displayed that each SBU was well-isolated, with significant antiferromagnetic coupling between CoII ions, leading to an S = 0 ground state. These interactions were then modelled using density functional theory. This type of study promotes the future development of novel high-nuclearity MOF structures with interesting and tuneable magnetic properties, as well as the potential for assembly of discrete molecular magnetic units in 3D using MOFs. Chapter 7 utilizes the principles of Chapter 3, wherein magnetic ions are doped into a diamagnetic material; in this case, MOF-5. We sought to isolate one CoII ion in each SBU, and build upon this by adding additional magnetic ions and probing their interactions. Through magnetic measurements we observed a scaling magnetic moment with CoII content, and with higher dopant percentages we began to observe magnetic interactions occurring within the SBUs. Interestingly, we also observed a change in coordination environment with higher dopant percentages, likely as a result of the previously suggested capability of one ZnII ion within the MOF-5 SBU to become hexacoordinate, allowing CoII doping up to a maximum of 25%. Consequently, this study points to the cause of the structural instability that plagues MOF-5 in the presence of air and moisture. We probed this system further in Chapter 8 using FeIII as a dopant ion, and were able to obtain the first crystallographic evidence of the coordination change of ZnII in MOF-5. Furthermore, the structure obtained with FeIII was the first example of metal ion addition within a MOF that bound two interpenetrated frameworks together. This new MOF was found to have the potential to be a more practical material for gas storage and separation, and/or for catalysis. Thus, this study was informative in regards to the inherent instability of the parent framework, as well as a new method of metal addition to a known MOF structure. Chapter 9 will conclude the work with a discussion of what was performed in, and learned from, each thesis section, as well as provide an outlook and perspective on the novel work that may be derived from these projects going forward.

An immediate reduction in global CO2 emissions could be accomplished by replacing coal- or oil-based energy sources with purified natural gas. The most important process involved in natural gas purification is the separation of CO2 from CH4, where Pressure Swing Adsorption (PSA) technology on porous materials has emerged as a less energy demanding technology. Among porous materials which are used or could potentially be used in PSA, Metal Organic Frameworks (MOFs) have attracted particular interest owing to their record-breaking surface areas, high-porosity, and high tunability. However, the discovery of optimal MOFs for use in adsorption-based CO2 separation processes is remarkably challenging, as millions of MOFs can potentially be constructed from virtually limitless combinations of inorganic and organic secondary building units. To overcome this combinatorial problem, this thesis aims to (1) identify important design features of MOFs for CO2/CH4 separation through the investigation of currently existing MOFs as well as the high throughput computational screening of a large database of MOFs, and to (2) develop efficient computational tools for aiding the discovery of new MOF materials. To validate the computational methods and models used in this thesis, the first work of this thesis presents the computational modeling of CO2 adsorption on an experimental CuBDPMe MOF using grand canonical Monte Carlo simulations and density functional theory. The simulated CO2 adsorption isotherms are in good agreement with experiment, which confirms the accuracy of the models used in our simulations throughout this thesis. The second work of this thesis investigates the performance of an experimental MIL-47 MOF and its seven functionalized derivatives in the context of natural gas purification, and compares their performance with that of other well-known MOFs and commercially used adsorbents. The computational results show that introducing polar non-bulky functional groups on MIL-47 leads to an enhancement in its performance, and the comparison suggests that MIL-47-NO2 could be a possible candidate as a solid sorbent for natural gas purification. This study is followed by the compactional study of water effects on natural gas purification using MOFs, as traces of water is present in natural gas under pipeline specifications. From the study, it is found that water has a marginal effect on natural gas purification in hydrophobic MOFs under pipeline specifications. Following the aforementioned studies, a database of 324,500 hypothetical MOFs is screened for their performance in natural gas purification using the general protocol defined in this thesis. From the study, we identify 'hit' materials for targeted synthesis, and investigate the structure-property relationships with the intent of finding important MOF design features relevant to natural gas purification. We show that layered sheets consisting of poly-aromatic molecules separated by a perpendicular distance of roughly 7 Å are an important structural-chemical feature that leads to strong adsorption of CO2. Following the screening study, we develop efficient computational tools for the recognition of high-preforming MOFs for methane purification using Machine Learning techniques. A training set of 32,500 MOF structures was used to calibrate support vector machines (SVMs) classifiers that incorporate simple geometrical features including pore size, void fraction and surface area. The SVM machine learning classifiers can be used as a filtering tool when screening large databases. The SVM classifiers were tested on ~290,000 MOFs that were not part of the training set and could correctly identify up to 70% of high-performing MOFs while only flagging a fraction of the MOFs for more rigorous screening. As a complement to this study, we present ML classifier models for CO2/CH4 separation parameters that incorporate separately the Voronoi hologram and AP-RDF descriptors, and we compare their performance with the classifiers composed of simple geometrical descriptors. From the comparison, it is found that including AP-RDF and Voronoi hologram descriptors into the classifiers improves the performance of classifiers by 20% in capturing high-performing MOFs. Finally, from the screening data, we develop a novel chemiformatics tool, MOFFinder, for aiding in the discovery of new MOFs for CO2 scrubbing from natural gas. It has a user-friendly graphical interface to promote easy exploration of over 300,000 hypothetical MOFs. It enables synthetic chemists to find MOFs of interest by searching the database for Secondary Building Units (SBUs), geometric features, functional groups and adsorption properties. MOFFinder provides, for the first time the substructure/similarity query of porous materials for users and is publicly available on titan.chem.uottawa.ca/moffinger.

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第22684号 / 理博第4625号 / 新制||理||1665(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)教授 北川 宏, 教授 吉村 一良, 教授 有賀 哲也 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

Thesis advisor: Jeffery A. Byers / Thesis advisor: Chia-Kuang (Frank) Tsung / Biological systems have evolved over time to favor structures beneficial for the efficient transformation of simple feedstocks to sophisticated products. In particular, enzymes have evolved such that cooperative and geometrically controlled interactions between active sites and substrates enhance catalytic activity and selectivity. Separation of these active sites from other incompatible catalytic components allows for chemical transformation in a stepwise fashion, circumventing the inherent limitations to performing reactions in a single step. This dissertation describes the use of porous crystalline materials called metal-organic frameworks (MOFs) as hosts to mimic the component separation and precise active site control observed in nature. The first phase of these efforts explores the use of dissociative “aperture-opening” linker exchange pathways in a MOF to encapsulate transition metal complexes for carbon dioxide hydrogenation to formate. This strategy is then used to separate two incompatible complexes and perform the cascade conversion of carbon dioxide to methanol, resulting in unique and previously unobserved network autocatalytic behavior. Finally, the modularity of the MOF host is leveraged to install beneficial functionality in close proximity to the encapsulated transition metal complex, leading to activity exceeding that of any reported homogeneous system for carbon dioxide reduction. The insights gained through these studies can inform the development of composites for other reactions, allowing for access to new and unique reaction manifolds. / Thesis (PhD) — Boston College, 2020. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.

Thesis advisor: Chia-Kuang Tsung / Thesis advisor: Dunwei Wang / Metal-organic frameworks (MOFs), as a type of inorganic-organic hybrid porous materials, have attracted enormous research interests over the past two decades due to their extraordinary variability and richness of their chemistry and structures. The original design on MOFs is in pursuit of and high surface area, typically for gas storage. However, the properties in a simple MOF system could not meet the needs for a wide variety of advanced applications. Therefore, it is highly desirable to introduce multiplicities and impart functionalities into MOFs through materials design. In this regard, this dissertation focuses on engineering MOFs in two strategies, constructing heterostructures, fabricating thin films, and evaluating their impact on catalysis and energy conversions. The first chapter focuses on constructing a well-defined interface between materials with vast differences in structural dimensions. Another highlight of this study lies in developing characterization protocols to characterize interfacial structures. In the second part, a MOF-74 thin film with crack-free nature serves as a promising platform for the study of ion transport. The last part of this dissertation reports a new two-dimensional (2D) structure derived from UiO-66. The 2D structure was attained by limiting the coordination number and inducing anisotropic growth. The layered material could be further exfoliated and fabricated into thin films. This work presents strategies to impart functionality to MOFs with rational material design and elucidate their positive impacts on the performance of the whole system. / Thesis (PhD) — Boston College, 2021. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.

Metal-organic frameworks (MOFs) constructed from metal atoms connected by organic linkers have received extensive attention for greenhouse gas separation in the past decades. Moreover, their large surface area makes them a promising candidate as adsorbents for gas sorption. This project aims to develop MOFs via different synthesis instructions by utilizing  Mg-containing materials, including Commercial MgCO3  and Mesoporous Magnesium Carbonate (Upsalite) as a source of the metal part and four different organic linkers. Water, Ethanol, Methanol, and N, N-dimethylformamide were used as solvents. First, synthesis was performed at room temperature, followed by high temperature using an autoclave and reactor. Then, the successfully synthesized samples were characterized by different characterization methods. These characterization techniques included Powder X-ray Diffraction (PXRD), Scanning Electron Microscopy (SEM), and Infrared Spectroscopy (IR).  Porous properties of the MOFs were tested by gas adsorption techniques, including N2  and CO2 as adsorbate gases. As a result, it was found that synthesized MOFs have a high surface area and porosity to adsorb greenhouse gases and separate CO2 from N2. The highest surface area, N2, and CO2 adsorption amounts were 539 m²/g, 0.32 (mmol/g at 293K,1bar), and 3.31 (mmol/g  at 293K,1bar), respectively. CO2  adsorption is approximately ten times N2  adsorption in almost all MOF synthesized samples. To achieve the best result regarding the high amounts of surface area, N2, and CO2  sorption,  synthesis at room temperature using Commercial MgCO3, H2dhbq linker, and water solvent was the best approach.

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第18641号 / 理博第4020号 / 新制||理||1579(附属図書館) / 31555 / 京都大学大学院理学研究科化学専攻 / (主査)教授 北川 宏, 教授 吉村 一良, 准教授 前里 光彦 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第19916号 / 理博第4216号 / 新制||理||1605(附属図書館) / 33002 / 京都大学大学院理学研究科化学専攻 / (主査)教授 北川 宏, 教授 島川 祐一, 教授 有賀 哲也 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM