Diamond is a unique material with excellent properties. As a result of the development within the area of CVD synthesis, doping and surface functionalization, diamond has become a strong candidate for use in electrochemical, electronic and biomedical applications. In this thesis, theoretical calculations have been used with the purpose to investigate various properties of the diamond surfaces. The effect of doping elements (N and B) on the stability of different surface terminations with X (where X = H, OH, Oontop or Obridge) has been investigated for a diamond (100) surface. As a result, the adsorption energy for all termination types was shown to decrease from the situation with a non-doped diamond surface, to the scenario with a N- (or B-doped) diamond thin film.. This result was found to correlate well with the changes of the calculated Csurface-X bond lengths. Furthermore, the spin density has been calculated and used to show the local distribution of the unpaired electron, which is the consequence of the introduction of dopants into the diamond slab. As a result, the spin density was found to be localized in the vicinity to the dopants for H- (or OH-) terminated diamond (100) surfaces. On the other hand, a delocalised spin density over the Oadsorbate and Csurface layer for Oontop- and Obridge-terminated surfaces, has also been observed. Moreover, the results of the pDOS calculations indicate the electron donating ability of N, and the hole donating ability of B. The Fermi level was shifted towards the lower conduction band edge for N-doped diamond, and towards the upper edge of the valence band edge for B-doped diamond. Hence, N-doped diamond will render n-type conductivity, and B-doped diamond will show p-type conductivity. In addition, an interesting observation was made for Oontop –terminated diamond surfaces. Localized electron conductivity, involving only this type of termination situation,, was also observed for N- (or B-) doped and completely  Oontop-terminated diamond surfaces. With the purpose of applying diamond substrates in the formation of epitaxial graphene, the annealing process of an ideal diamond (111) surface has also been simulated in the present work. It was thereby shown that high temperatures (over 2000 K) will be required for the epitaxial formation of graphene ontop of the diamond (111) surface. However, in the presence of hydrogen radicals (by saturating the radical sites in the system), the required temperature was observed to decrease to 1000 K. In addition to these MD simulations, by using an interlayer iron ontop of the diamond (111) surface, the adhesion energies between the graphene and the Fe//diamond slab, as well as the adhesion energy between the graphene//Fe layer and the diamond (111) surface, have been calculated. Thereby, the interaction between the graphene and Fe layer was obtained to be very weak, and of an electrostatic type. On the other hand, the interaction between the Fe interlayer and the diamond substrate was calculated as a moderately strong covalent bond. Moreover, the changes in these interactions, correlating to the changes in the pDOS spectra of graphene, Fe and diamond, gave a tendency of one-dimensional quantum size effect, depending on the thickness of Fe interlayer.

Polymeric hollow fiber sorbents were functionalized with amine moieties for improving the carbon dioxide sorption capacity from flue gas to reduce the greenhouse gas emissions from coal-fired power plants. Three different experimental pathways were studied to form the amine-functionalized hollow fiber sorbents. Aminosilane functionalized cellulose acetate (CA) fibers, polyethyleneimine (PEI) functionalized polyamide-imide (PAI, Torlon® fibers and PEI post-infused and functionalized Torlon®-silica fibers were formed. CO₂ equilibrium sorption capacity data were collected by using the pressure decay sorption cell and thermal gravimetric analyzer. Other physio-chemical properties of the amine-functionalized fiber sorbents were characterized by using fourier-transform infrared spectroscopy, elemental analysis, and scanning electronic microscopy. Different reaction conditions were studied on the effect of sorption isotherms. Aminosilane-CA fibers were the first proof-of-concept for forming the amine functionalized polymer hollow fibers. PEI-PAI fibers were designed as a new method to reach enhanced sorption capacities than Aminosilane-functionalized CA fibers. PEI post-infused and functionalized Torlon®-silica fibers have further enhanced sorption capacity; however they easily degrade with similar reaction for forming PEI-PAI fibers. Lumen-side barrier layers were created successfully via post-treatment technique of using the crosslinked Neoprene® polymer onto PEI-functionalized PAI fibers. PEI-functionalized PAI fibers also have good cyclic stability and low heat of sorption.

The development of new, improved methods for forming carbon–carbon and carbon–heteroatom bonds is the basic goal in synthetic organic chemistry. In the Lautens group, many recent advances have been made using late transition metals such as rhodium and palladium. One such research project involves the synthesis of indoles through tandem C–N and C–C coupling reactions using gem-dibromoolefin starting materials, and this area serves as a starting point for the research described. Chapter 1 describes a method by which the tandem use of gem-dibromoolefins can be halted to give intramolecular monocoupling reactions, maintaining one of the carbon–bromine bonds which can serve as a useful handle for further functionalization. The use of copper as a catalyst is key to this reaction, as it features a unique mechanism for carbon–heteroatom bond formation. Benzofurans and benzothiophenes can be prepared by this method. Chapter 2 describes the synthesis of 2-bromoindoles using an intramolecular Buchwald–Hartwig amination of gem-dibromoolefins. It is found that the products are more reactive towards palladium(0) than the starting material, and the use of a bulky phosphine ligand which facilitates reversible oxidative addition is required. This represents one of the first catalytic applications of this step in synthesis. Chapter 3 further explores the concept of reversible oxidative addition in a novel carbohalogenation reaction of alkenes. Aryl iodides tethered to alkenes are treated with a palladium(0) catalysts, which can undergo the basic steps of oxidative addition, carbopalladation, and novel sp2 carbon–iodine reductive elimination. This process is remarkably simple in concept, and is a waste-free, atom economically method for preparing new carbon–carbon bonds. Chapter 4 discusses various limitations to the carbohalogenation methodology, and seeks to overcome these problems. The use of aryl bromide starting materials can be accomplished by adding an iodide source to the reaction, allowing halide exchange of palladium(II) intermediates to occur. Intermolecular and asymmetric variants are also explored. Computational studies are discussed which reveal useful mechanistic details of the catalytic cycle, and this information is used in the development of novel phosphine ligands.

This thesis is based on two main parts. The first part concerns purification and functionalization of carbon nanotubes (papers I-III), and the second part is related to the synthesis of organometallic fullerene derivatives (papers IV-VII): Two oxidative methods involving aqueous nitric acid were compared with respect to their capability to introduce carboxylic groups into single walled carbon nanotubes, and several literature methods for esterification and amidation of these groups have been evaluated with focus on efficiency and reproducibility in forming covalently functionalized products soluble in organic media. Amidation proceeding via a SWNT-(COCl)n intermediate yielded the expected covalent product, whereas carboxylate salt formation dominated with other attempted methods. Esterification was achieved via the acyl chloride method and via alkylation of SWNT-(COO–)n, the latter being the more efficient method. A new, reagent-free method for purification of single- and multi walled carbon nanotubes has been developed. Microwave treatment dissociates non-nanotube carbon and disperses it into an organic solvent, resulting in very pure carbon nanotubes within a few minutes of heating, without the involvement of acidic/oxidative reagents. According to thermogravimetric analysis, Raman and IR spectroscopy, as well as SEM, the process yields nanotubes with a low degree of defects. A non-covalent approach has been employed to prepare nanotubes functionalized with glycosides. Derivatives of galactose and lactose were covalently linked to a pyrene moiety and the thus formed pyrene-glycosides were non-covalently attached to single- and multi walled carbon nanotubes by π-π interactions. Fluorescence titrations have been used to quantify the formed supramolecular assemblies, which for SWNTs exhibits increased water solubility. A fulleropyrrolidine-(tricarbonyl)chromium complex was synthesized and fully characterized. IR spectroelectrochemistry was used to probe the redox state of the fullerene and provided evidence for electronic communication between the two electroacive moieties. A C60-ferrocene-C60 triad system was synthesized and characterized. Cyclic voltammetry and fluorescence studies suggested electronic communication between ferrocene and the two fullerenes. Finally, the synthesis and initial characterization of short fullerene-ferrocene oligomers are presented.

京都大学 / 新制・課程博士 / 博士(理学) / 甲第23021号 / 理博第4698号 / 新制||理||1674(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)准教授 齊藤 尚平, 教授 時任 宣博, 教授 依光 英樹 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

京都大学 / 新制・課程博士 / 博士(理学) / 甲第23022号 / 理博第4699号 / 新制||理||1674(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 時任 宣博, 准教授 加納 太一, 教授 依光 英樹 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

One of today’s world's main challenges is access to a clean environment. The release of hazardous and toxic gases from burning fossil fuels is of critical concern due to these gases' destructive effects on the nearby atmosphere. Among these, acid rain is one of the most severe consequences of air pollution caused by sulfur dioxide (SO2) gas and still needs to be better addressed. One of the solutions is the adsorption-based technologies because of their ease of use, possible high adsorption capacity, minimum environmental impact, low cost, and efficient sorbate recovery possibilities. Gas separation via adsorption is not yet widely employed commercially since it needs regenerable, high-durable, high-performance, and cost-effective adsorbents. One of the common methods of absorbing acid gases is the use of amino absorbents that have disadvantages such as create many waste materials challenging to regenerate, wastewater, and waste gas. Therefore, incorporating amine groups on the surface of solids to overcome the problem of regeneration has attracted considerable attention in gas uptake. In this project, we proposed to functionalize nanocrystalline cellulose (NCC) using a solvent-free method to boost their SO2 interactions and thus their adsorption capability. Therefore, a commercial NCC material was modified using ethylenediamine (EDA) in green and straightforward amination approach in order to tune its surface basicity and obtain an efficient green-biobased adsorbent. Since the substitution process of amines with hydroxyl groups on the cellulose surface is carried out through dangerous halogen solvents, we used the solvent-free one-step method and investigated the synthetic parameters. Amination conditions of NCC adsorbents were optimized via the effects of the amination temperature, the amination time, and the amount of EDA on their physical properties and their performance for SO2 adsorption. The sorbents were characterized using attenuated total reflection-Fourier-transform infrared spectroscopy (ATR-FTIR), solid carbon nuclear magnetic resonance (13CNMR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy- energy-dispersive X-ray spectroscopy (SEM-EDS) to see if EDA was incorporated into the NCC and investigate the changes in thermal stability of adsorbents by changing synthesis conditions. Sorbents were then tested for SO2 capture at the same conditions of room temperature (RT), atmospheric pressure, and a flow rate of 20 ml/min, which was selected based on previous studies to optimize flow rate in the same research group. The optimal conditions to create an effective sulfur dioxide adsorbent were found to be 70 oC for 8 hours of amination. At ideal conditions, the NCC modified had an SO2 adsorption capacity value of 0.030 mg/100 mg. The promising properties of EDA-NCC in terms of adsorption capacity (showing a significant increase in capacity when compared to the NCC at atmospheric pressure and ambient temperature) make them potential adsorbent candidates. In addition, the impacts of SO2 capture operating conditions on adsorption capacity were evaluated. By varying the adsorption temperature from room temperature to 60 °C and the feed flow rate from 10 to 30 ml min-1, fixed-bed breakthrough studies for SO2 adsorption onto NCC and modified-NCC adsorbent (prepared at 70oC, 3hr, and EDA/NCC=25) were carried out. Over the range of operating parameters studied, the greatest SO2 capacity and breakthrough time values were obtained with adsorbent at room temperature and 20 ml min-1 input flow rate. As expected, due to the exothermic nature of the adsorption process, the amount of SO2 adsorbed at equilibrium decreased with increasing temperature. It was also observed that as the flow rate increases, the breakthrough time decreases due to the higher flow rate of the feed gas was accompanied by the faster transport of the adsorbate molecules and leading to a shorter breakthrough time, as expected. Finally, another EDA functionalization method was tested, using a two-step method. First, cellulose was functionalized using citric acid (CA), and then the EDA was incorporated via carboxylic acid functional groups in the CA to obtain both amide and amine groups on the NCC’s surface. This approach aimed to compare EDA deposition on cellulose surface via a different method by adding one more functional group and evaluating their performance in SO2 gas adsorption. It was concluded that oxygenated functional groups and groups with low alkalinities, such as carboxylic acid and amide, can negatively affect gas adsorption. These results were concluded by comparing two adsorbents, one containing only amine groups and the other adsorbent containing amide and carboxylic acid groups in addition to the amine group, although the amine content of the two adsorbents was different. Future research will explore the mechanisms and capturing phenomena to improve capturing capacity and process applicability as well as the material optimal regeneration operating conditions.

Sulfones are useful bioisosteres in drug discovery, and have an unusual ability to engage in binding with both polar and nonpolar regions of target proteins. Despite this, they have seen limited use in drug-screening campaigns, compared with other functional groups. With the goal of generating a library of bicyclo[3.2.1]sulfone-containing molecules to probe biological function, a tandem 1,2-addition/anionic oxy-Cope/1,2-addition reaction proceeding from 3-sulfolene and discovered by previous members of our group was used to prepare highly substituted scaffolds for diversification. Functional group manipulations on this scaffold were partially successful, but ultimately provided limited scope for exploring three-dimensional space. Moving to a less-substituted bicyclo[3.2.1]sulfone scaffold that could be accessed using methodology developed by the Chou group, it was found that a greater range of chemical diversification could be achieved. Using both substrate-directed methods and intrinsic functional group reactivity, about 70% of the skeletal framework was functionalized with high levels of regioselectivity and (in some cases) good levels of diastereoselectivity. Chemoinformatic analysis was performed on our collection of synthesized bicyclo[3.2.1]sulfone-containing molecules, and diverse molecular descriptors were obtained. Collaborations were established with industrial partners and non-profit institutions for the purpose of determining biological properties in medicinally relevant areas. Significantly, each of these partners joined the project with therapeutic expertise in a different field (oncology, neurodegenerative diseases, antimicrobial agents, and skin inflammation), thereby maximizing the chances of finding useful lead compounds for future development. Preliminary biological screening data were obtained, which suggest future potential for sulfone-containing conformationally restricted small molecules to be impactful in therapeutic development. / Graduate

Multiple hurdles, such as drug solubility, stability, and physical barriers in the body, hinder bioavailability of many promising therapeutics. Polymeric nanocarriers can encapsulate the therapeutics to protect non-target areas from side effects but also protect the drug from premature degradation for increased circulation and bioavailability. To capitalize on these advantages, the polymer nanoparticle must be properly engineered for increased control in size distribution, therapeutic encapsulation, colloidal stability, and release kinetics. However, each application requires a specific set of characteristics and properties. Being able to tailor these by manipulation of different design parameters is essential to optimize nanoparticles for the application of interest. This study of nanoparticle fabrication and characterization takes us a step closer to building effective delivery systems tailored for specific treatments. Poly(ethylene oxide)-b-poly(D,L-lactic acid) (PEO-b-PDLLA) based nanoparticles were produced to range from 100-200 nm in size. They were fluorescently labeled with a hydrophobic dye 6-13 bis(triisopropylsilylethynyl) pentacene (TIPS pentacene) at an optimal loading of 0.5 wt% with respect to the core. Surfaces were successfully coated with streptavidin to be readily functionalized with various biotinylated compounds such as PD-L1 antibodies or A488 fluorophore. Using the same PEO-b-PDLLA, iron oxide and a conjugated polymer poly(2- methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV) were co-encapsulated to form fluorescently labeled magnetic particles. Using poly(lactic-co-glycolic acid), CRISPR-Cas9 plasmids were encapsulated at 1.6 wt% and most of the payload released within the first 24 hours. The incorporated plasmids were intact enough to have mammalian macrophages successfully express the bacterial protein Cas9. Using similar PLGA based particles, the surface was functionalized with streptavidin and bound to the surface of bacteria as an active carrier for increased penetration of solid tumors averaging ~23 particles per bacterium. PEO-b-PLGA based particles were used in conjunction with a hydrophobic salt former to encapsulate a peptide designed to reduce platelet binding to cancer cells and mitigate extravasation. The peptide encapsulated was increased from < 2 wt% without salt former to 8.5 wt% with the used of hexadecyl phosphonic acid. Although the applications across these projects can be broad, the fundamentals and important design parameters considered contribute to the overarching field of effective carriers for drug delivery. / Ph. D. / There are many reasons why many promising pharmaceutical formulations never make it through regulation and onto market, including low solubility of the drug, low absorbance by the body, and harmful side effects, to name a few. Using polymer drug carriers, these difficulties can be overcome by holding the drug in a more soluble carrier, releasing it on a certain timeline or to a specific location to increase absorbance and decrease side effects. When designing a carrier, the requirements for the product are dependent on the application and the disease of interest. This work looks at the material types and conditions during particle formation to see how it affects the final product to better define and understand how these parameters change the performance. This work shows that the carrier size can be manipulated depending on how much of one material is used versus the other, they can be labeled to fluoresce so they can be tracked during cell and animal studies, and they can be coated with targeting compounds on the surface to increase the specificity of the carrier to localize to a target location of interest. Different particles containing DNA for gene editing, peptides for cancer therapies, and magnetic iron oxides to increase transport across difficult cell barriers have all be fabricated and characterized. The lessons learned through these projects will help guide future work to more effective and efficient delivery of pharmaceuticals to the body.

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