Electrospinning is a novel technique to fabricate non-woven fibers with sizes ranging from nano to micrometers. Polymers have been electrospun into nanofibers that can be developed into desirable materials with excellent biocompatibility and biodegradability for biomedical applications in wound healing and tissue regeneration. These nanofiber materials can be further functionalized to be loaded with bioactive molecules, including antibacterial agents, functional proteins that promote tissue reconstruction while protect host tissues from contamination. This study focuses on the development of multifunctional nanofibers that are incorporated with antibacterial drug(s) and immobilized with bioactive proteins. These nanofibers are potentially useful for wound care and tissue engineering scaffolding to provide both infection control and promotion of wound healing or tissue regenerations.

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 methods for site-selective derivatization of natural products to enable simultaneous arming and structure activity relationship (SAR) studies has shown great potential for the synthesis of pharmaceutical drug leads and cellular probes for mechanism of action studies. Herein, we describe a strategy to functionalize carboxylic acid and phenol containing natural products. This methodology relies on the in situ generation of diazoalkanes to form the corresponding carbonyl esters and phenolic ethers derived from natural products. We applied this process to several natural products, to begin demonstrating the utility of this methodology for the simultaneous arming and SAR studies of natural products. To expand our group’s nucleophile catalyzed aldol lactonization (NCAL) reaction for synthesizing highly substituted cyclopentane fused beta-lactones, we developed a nucleophile catalyzed, tandem Michael aldol lactonization (NCMAL) reaction. Herein, we show the synthetic utility of this reaction in varying the Michael donors and acceptors, developing a catalytic, enantioselective NCMAL, and synthesizing tricyclic-!-lactones. Furthermore, we initiated studies toward applying this new methodology to the synthesis of a lipase inhibitor, vibralactone.

abstract: Zinc oxide nanowires ( NWs) have broad applications in various fields such as nanoelectronics, optoelectronics, piezoelectric nanogenerators, chemical/biological sensors, and heterogeneous catalysis. To meet the requirements for broader applications, the growth of high-quality ZnO NWs and functionalization of ZnO NWs are critical. In this work, specific types of functionalized ZnO NWs have been synthesized and correlations between specific structures and properties have been investigated. Deposition of δ-Bi2O3 (narrow band gap) epilayers onto ZnO (wide band gap) NWs improves the absorption efficiency of the visible light spectrum by 70%. Furthermore, the deposited δ-Bi2O3 grows selectively and epitaxially on the {11-20} but not on the {10-10} facets of the ZnO NWs. The selective epitaxial deposition and the interfacial structure were thoroughly investigated. The morphology and structure of the Bi2O3/ZnO nanocomposites can be tuned by controlling the deposition conditions. Various deposition methods, both physical and chemical, were used to functionalize the ZnO NWs with metal or alloy nanoparticles (NPs) for catalytic transformations of important molecules which are relevant to energy and environment. Cu and PdZn NPs were epitaxially grown on ZnO NWs to make them resistant to sintering at elevated temperatures and thus improved the stability of such catalytic systems for methanol steam reforming (MSR) to produce hydrogen. A series of Pd/ZnO catalysts with different Pd loadings were synthesized and tested for MSR reaction. The CO selectivity was found to be strongly dependent on the size of the Pd: Both PdZn alloy and single Pd atoms yield low CO selectivity while Pd clusters give the highest CO selectivity. By dispersing single Pd atoms onto ZnO NWs, Pd1/ZnO single-atom catalysts (SACs) was synthesized and their catalytic performance was evaluated for selected catalytic reactions. The experimental results show that the Pd1/ZnO SAC is active for CO oxidation and MSR but is not desirable other reactions. We further synthesized ZnO NWs supported noble metal (M1/ZnO; M=Rh, Pd, Pt, Ir) SACs and studied their catalytic performances for CO oxidation. The catalytic test data shows that all the fabricated noble metal SACs are active for CO oxidation but their activity are significantly different. Structure-performance relationships were investigated. / Dissertation/Thesis / Doctoral Dissertation Materials Science and Engineering 2017

Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第15674号 / 工博第3332号 / 新制||工||1503(附属図書館) / 28211 / 京都大学大学院工学研究科高分子化学専攻 / (主査)教授 中條 善樹, 教授 澤本 光男, 教授 赤木 和夫 / 学位規則第4条第1項該当

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Diamond has since many years been applied in electronic fields due to its extraordinary properties. Substitutional dopants and surface functionalization have also been introduced in order to improve the electrochemical properties. However, the basic mechanism at an atomic level, regarding the effects of dopants and terminations, is still under debate. In addition, theoretical modelling has during the last decades been widely used for the interpretation of experimental results, prediction of material properties, and for the guidance of future materials. Therefore, the purpose of this research project has been to theoretically investigate the influence of dopants and adsorbates on electronic and geometrical structures by using density functional theory (DFT) under periodic boundary conditions. Both the global and local effects of dopants (boron and phosphorous) and terminations have been studied. The models have included H-, OH-, F-, Oontop-, Obridge- and NH2-terminations on the diamond surfaces. For all terminating species studied, both boron and phosphorous have been found to show a local impact, instead of a global one, on diamond structural geometry and electronic properties. Therefore, the terminating species only affect the DOS of the surface carbon layers. In addition, Oontop-terminated (111) diamond surfaces present reactive surface properties and display metallic conductivity. Moreover, the conductivity of the diamond surface can be dramatically increased by the introduction of a phosphorous dopant in the lattice. The work function of a diamond surface has also been found to be influenced to a large extent by the various adsorbates and the dopant levels. Diamond can also be used as a promising substrate for an epitaxial graphene adlayer. The effects of dopants and terminations on the graphene and diamond (111) interfacial systems have been investigated theoretically in great detail. The interfacial interaction is of the Van der Waal type with an interfacial distance around 3 Å. The interactions between graphene and a terminated diamond substrate were found to be relatively weaker than those for a non-terminated diamond substrate (even with dopants). For all interface systems between graphene and diamond, a diamond-supported graphene adlayer without induced defects can still keep its intrinsic high carrier mobility. A minor charge transfer was observed to take place from the graphene adlayer to a non-terminated diamond substrate (with or without dopants) and to Oontop-, OH- or Obridge-terminated diamond substrates. However, for the situation with an H-terminated diamond surface, the electron transfer took place from the diamond surface to graphene. On the contrary, an interfacial system with a non-terminated diamond surface offers a more pronounced charge transfer than that of the terminated diamond substrates. A small finite band gap at the Dirac point was also observed for the Oontop-terminated diamond-supporting graphene adlayer.

Graphene, a two dimensional monolayer carbon sheet with the atoms tightly packed in a hexagonal lattice, has exhibited so many excellent properties, which enable graphene to break several material records with regard to carrier mobility, strength yield and thermal conductivity to name a few. Therefore, graphene has been placed as a potential candidate to allow truly next-generation material. Graphene is a zero band gap material, implying that an energy band gap around the Dirac point is supposed to be open to make graphene applicable as a semiconductor. Covalent bond graphene functionalization becomes an essential enabler to open the energy gap in graphene and extend graphene applications in electronics, while the densely packed hexagonal carbon atoms as well as the strong sp2 hybridization carbon-carbon bonds jointly result in a changeling topic of allowing graphene to be decorated with functional groups. Here in this thesis, different routes to realize graphene functionalizations are implemented by using physical and chemical ways. The physical functionalization methods are the ion/electron beam induced graphene fluorination as well as local defect insertion and the chemical ways correspond to the photochemistry techniques to approach hydrogenation and hydroxypropylation of graphene. Furthermore, to incorporate graphene into devices, the tuning of mechanical properties of graphene is desired. Towards this aim, the structure modification of graphene is employed to investigate the nanometer size-effect of crystalline size of graphene on the mechanical properties, namely Young’s modulus and surface energy. In the process of the graphene hydrogenation project, we discovered a high yield way to synthesis high quality graphene nanoscroll (GNS). Interestingly, the GNS shows superadhesion property through our atomic force microscopy measurements. This superadhesion is around 6-order stronger than van der Waals interaction and even higher than the hydrogen bonding enhanced and solid/liquid interfaces.

Presented herein is the development, optimization and mechanistic investigation of an Cu catalytic system for the oxidation of sp 3 C-H bond of simple arenes to form C-N bond in a direct manner. Due to the prevalence of nitrogen containing molecules among biologically active synthetic and natural compounds, synthetic chemists have always been motivated to develop new efficient ways to directly transform ubiquitous carbonhydrogen (C-H) bonds into carbon- nitrogen (C-N) bonds. Recent advances in transition metal catalyzed C-H amination has demonstrated that it is not only possible but also practical to functionalize C-H bonds that are often considered inert in one step, circumventing more classical, sequential functional group interconversion approaches. Existing catalytic systems that promote the transition metal-catalyzed, amination of sp 3 C-H bonds displayed certain limitations, especially the lack of built-in versatility and stability in their amination reagents. To overcome these drawbacks of these existing catalytic system, our group developed a new Cu amination protocol that deployed versatile hydroxylamine-based with general structure RSO 2 NH-OAc as amination reagents. Although the reactivity of the catalytic system ranges from moderate to good, the catalytic system provided promising results using simple arene substrates. Further detailed mechanistic studies revealed that the reaction undergoes an unprecedented two subsequent cycles divided by a major intermediate PhCH 2 (NTsOAc). The proposed mechanism is consistent with radical clock experiments, observed reaction profiles, the need for excess of substrate, and the documented role of the ligand in the catalytic system. The exciting proposed mechanism led to a new type of copper catalyzed amination reaction using N- fluorobenzenesulfonimide (NFSI) as oxidant, which overcomes the need to use an excess of substrate. A wide range of unactivated amines HNR 1 R 2 , including sulfonamide and benzamide, can be used as amine sources, which enables the installation of different nitrogen groups on benzylic sp 3 C-H bond of a variety of substrates in moderate to excellent yield. Moreover, mechanistic experiments and critical analysis of related reactivity in the literature provide insight into the catalytic cycle, resulting in a proposal that details the role of both oxidant and amine source in the new system.

Catalyst-Controlled Divergent C–H Functionalization of Unsymmetrical 2-Aryl Cyclic 1,3-Dicarbonyl Compounds with Alkynes and Alkenes A problem faced within the area of C–H functionalization is achieving siteselectivity when several similar C–H bonds are present within a given compound. One solution to this problem is the development of reactions that employ different catalytic systems to control the required selectivity. Herein, it is shown that such catalyst-controlled selectivity could be achieved on 2-aryl cyclic 1,3-dicarbonyl compounds where there exist two potential, non-adjacent sites for C–H functionalization. Examples demonstrate the palladium- and ruthenium-catalysed oxidative annulations of the 2-aryl cyclic 1,3-dicarbonyl substrates with alkynes, as well as with alkenes, where initial C–H bond cleavage occurs at one of two potential sites, depending on the catalyst used, which give unique products. 1,4-Rhodium(III) Migration in the One-Carbon Oxidative Annulations of 2-Arylphenols, Benzamides, and Benzoic Acids with 1,3-Enynes Oxidative annulations of 2-arylphenols, benzamides, and benzoic acids with alkynes and enynes are precedented and provide a range of heterocyclic products. However, in these examples, either the alkyne or enyne acts as a two-carbon annulation partner, reacting only across the alkynyl moiety. Herein, a more expansive scope of a previously published process in which 1,3-enynes, possessing allylic hydrogen atoms cis to the alkyne, undergo oxidative annulations with the three aforementioned classes of substrates as a one-carbon annulation partner is described. Proposed to occur via the 1,4-migration of a rhodium(III) species, annulated products were formed from a range of 1,3-enynes and substrates possessing a variety of functional groups.