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Environmental and energy issues have stimulated renewed interest in utilizing both water and methanol as reagents and reaction mediums. Our current interest is to evaluate the scope of group nine organometallics and establish thermodynamic parameters for their reactivity in aqueous solvent. A comprehensive thermodynamic database for a wide scope of organo-rhodium transformations in a range of reaction media including benzene, water, and methanol has been well established by our group. Aqueous solutions of rhodium porphyrin have been determined to manifest an exceptional range of substrate reactions with carbon monoxide, dihydrogen, olefins, methanol and aldehydes. This study will focus on expansion of the thermodynamic database to all the group nine metals, particularly the iridium porphyrin systems in both water and methanol. Substrate reactivity and development of new mechanistic strategies for the conversion of carbon monoxide, alkanes, and alkenes to organic oxygenates are central objectives. Water/Methanol soluble porphyrin iridium complexes including iridium tetrakis(p-sulfonatophenyl)porphyrin ((TSPP)Ir) and iridium tetrakis(3,5-sulfonatomesityl)porphyrin ((TMPS)Ir) derivatives can be prepared by sulfonation of tetra phenyl porphyrin (H2TPP) and tetra mesityl porphyrin (H2TMP). The reactivity of dihydrogen with aqueous solutions of iridium(III) tetrakis(p-sulfonatophenyl)porphyrin ((TSPP)Ir(III)) complexes produce equilibrium distributions between six iridium species including iridium hydride ([(TSPP)Ir-D(D2O)]-4), iridium(I) ([(TSPP)IrI(D2O)]-5), and iridium (II) dimer ([(TSPP)IrII(D2O)]2-8) complexes. Each of these types of iridium porphyrin species including Ir(I), Ir(II), Ir(III), Ir-H, and Ir-OH function as precursors for a range of organometallic substrate reactions. A primary objective is to define the quantitative relationships pertaining to the distribution of species in aqueous solution as a function of the dihydrogen and hydrogen ion concentrations through direct measurement of five equilibrium constants along with free energy changes of coordinated water and free energy changes of reactions of dihydrogen in water. Reactivity, kinetics and evaluation of equilibrium thermodynamics, including the reactions of iridium hydroxide and methoxide with olefins to produce beta-hydroxyalkyl and beta-methoxyalkyl complexes, reactions of iridium hydride and olefins to produce iridium alkyl complexes, and reactions of iridium hydride with carbon monoxide to produce iridium formyl [Ir-CHO] complexes are also objectives of this research. Another research goal is the design and synthesis of diporphyrin ligands that form dimetal complexes capable of preorganizing transition states for substrate reactions that involve two metal centers. Dirhodium dimetalloradical complexes are observed to manifest large rate increases over mono-metalloradical activation reactions of hydrogen, methane, and other small molecule substrates. In this study, synthesis of diporphyrin (bisporphyrin) ligands and other ligands which will permit dimetallo complexes like anti-aromatic [14]annulene and low steric porphine ligands will be also be examined. / Chemistry

京都大学 / 新制・課程博士 / 博士(工学) / 甲第24639号 / 工博第5145号 / 新制||工||1983(附属図書館) / 京都大学大学院工学研究科合成・生物化学専攻 / (主査)教授 杉野目 道紀, 教授 中尾 佳亮, 教授 藤原 哲晶 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

The two projects described in this dissertation demonstrate the wide utility of noble metal N-heterocyclic carbene (NHC) complexes. The first project details the design of iridium NHC amino acid complexes for asymmetric transfer hydrogenation (ATH) of prochiral ketones. Iridium(I) bis-NHC complexes were found to undergo oxidative addition with a variety of alpha-amino acids, generating chiral iridium(III) complexes of the form Ir(NHC)2(aa)(H)(X) (aa = amino acid, X = halide). The complexes were screened for ATH of aryl and alkyl ketones, and optimization studies found enantioselectivity in this system was highly sensitive to the reaction temperature, NHC ligand, and amino acid. Incorporation of secondary amino acids was essential to enantioselectivity. Aryl ketones were reduced in high conversion and enantioselectivity when employing the Ir(IMe)2(L-Pro)(H)(I) catalyst in isopropyl alcohol, in some cases giving over 90% ee of the alcohol products. Density functional theory calculations were conducted in order to gain insight into the active catalytic species, and the results suggest that the high enantioselectivity of this system primarily arises from steric effects. The second project details the design of rhodium and iridium NHC piano-stool complexes featuring derivatized tetramethylcyclopentadienyl ligands (Cp*R, R = alkyl or aryl substituent) for antimicrobial applications. Complexes of the form (Cp*R)M(NHC)Cl2 (M = Rh or Ir) were synthesized by transmetallation of the NHC ligand using silver(I) oxide in the presence of the desired noble metal Cp*R dimer. The complexes were screened for biological activity against various bacteria, yeast, and fungi. Many of these compounds were highly active against Mycobacterium smegmatis, displaying minimum inhibitory concentrations (MICs) as low at 0.25 microgram per mL. Analysis of structure-activity relationships found that incorporation of the NHC ligand greatly enhances the antimicrobial properties of rhodium and iridium piano-stool complexes, more so than previously investigated diamine, amino acid, or beta-diketonato ligands. Cytotoxicity studies on one of the rhodium NHC complexes showed this compound was nontoxic towards mammalian cells at low concentrations, which strengthens the potential of these types of compounds as viable drug candidates. / Doctor of Philosophy / This dissertation describes two practical applications of a series of complexes featuring the noble metals rhodium and iridium. In all of these complexes, the metal center is bonded to one or two groups known as N-heterocyclic carbenes (NHCs). The most common structural variant of NHCs are five-membered rings. The metal is usually bonded to a carbon atom on these rings, which is flanked by two nitrogen atoms. Noble metal complexes containing NHCs are widely investigated in contemporary chemical literature for a variety of reactions, primarily because noble metals form exceptionally strong bonds with NHCs, making these complexes very stable. N-Heterocyclic carbene compounds are also fairly easy to synthesize and structurally modify, which allows fine-tuning for specific applications. The first project in this dissertation employed iridium NHC amino acid complexes for the selective production of alcohols, meaning only one structure of the alcohol product is favorably generated. This is an important transformation in the chemical and pharmaceutical industries, which often require the synthesis of highly pure products. These complexes were found to be quite successful for this application on a range of model substrates, in some cases generating as high as 95% of one alcohol product over the other. Product selectivity was found to depend on the specific structure of the NHC compound. The second project investigated the antimicrobial properties of rhodium and iridium NHC complexes. In recent years, the growing threat of antimicrobial resistance against traditional pharmaceuticals has led to an interest in the development of metal-based drugs, which may allow for metal-specific mechanisms of drug action that are not possible for commonly employed antimicrobial agents. These NHC complexes were screened for biological activity against various bacteria, yeast, and fungi. Many of the complexes displayed high activity against Mycobacterium smegmatis, comparable to those displayed by other clinical drugs such as ampicillin or streptomycin. These results were highly encouraging, as Mycobacterium smegmatis often serves as a model to study other mycobacteria.

Rh(III) and Ir(III) dimeric complexes with tunable cyclopentadienyl (Cp) rings have proven versatile for both catalysis and as synthetic precursors. An efficient microwave method to synthesize Rh(III) and Ir(III) dimeric complexes [(η5-ring)MCl]2(μ2-Cl)2, (where (η5-ring)MCl = (η5-Me4C5R)Rh(III)Cl or (η5-Me4C5R)Ir(III)Cl) was developed. A modular design for the substituted cyclopentadienes HC5Me4R was based on Grignard reactions of 2,3,4,5-tetramethylcyclopent-2-en-1-one (R = alkyl, 12 examples; R = aryl, 3 examples) or by SNAr reactions of potassium tetramethylcyclopentadienide with perfluoroarenes (R = perfluoroaryl, 3 examples). Reaction of the Me4CpHR ligands with [M(COD)](μ2-Cl)2 (M = Rh, Ir; COD = 1,5-cyclooctadiene) produced the dimeric complexes [Cp*RMCl]2(μ2-Cl)2 in moderate to excellent yield. The resulting dimers were characterized by nuclear magnetic resonance (NMR) spectroscopy, single-crystal X-ray diffraction (XRD), high-resolution mass spectrometry (HRMS), elemental analysis, and examined as catalysts for oxidative lactonization of 1,4- and 1,5-diols. Oxidative lactonization of 1,4-butanediol to afford γ-butyrolactone proceeded selectively and efficiently using [(η5-Me4C5R)IrCl]2(μ2-Cl)2 as the catalyst. Several R substituents were tested to assess electronic substituent effects. The most active complex contained an electron donating group, R = CHMe2 and successfully catalyzed the formation of diols to lactones across a range of 1,4- and 1,5-diols, generally in high yield. Computational analysis of the rate-determining b-hydrogen elimination reactions provided an atomistic account of observed trends in reaction yield and selectivity as a function of substrate structure, while accounting neatly for the observed selective formation of lactones (vs. succinaldehyde) in the transfer dehydrogenation of 1,4-butyrolactone. / Doctor of Philosophy / Rhodium(III) and iridium(III) complexes are useful synthetic precursors, catalysts, and biologically active compounds. This dissertation explores a rapid synthesis of these metal complexes and their subsequent catalytic applications with 1,4- and 1,5-diols. The oxidative lactonization of diols with rhodium and iridium complexes is an attractive one-pot synthesis, opening a variety of lactones to be produced. Structural studies involving novel fluorinated rhodium and iridium chloro-bridged dimers are discussed in detail.

This dissertation describes the design and synthesis of a series of half-sandwich amino acid complexes of the form), (aa = α-amino carboxylate), and their utility as asymmetric transfer hydrogenation catalysts of ketones. Variation of the metal center, the n-ring, and the aa was used to tune these systems for specific sets of ketones. Upon reaction with homochiral]s, the ligand environment in all of these complexes is pseudotetrahedral, leading to stereogenic metal ions (SM, RM). The addition of another stereogenic center from the amino acid ligand (the carbon, RC or SC;glycine) gives rise to two pairs of diastereomeric complexes. / Ph. D.

This dissertation describes the synthesis and antimicrobial use of a series of half-sandwich Ir(III), Rh(III), Co(III) amino acid and ethylenediamine complexes. This investigation focuses on the formulation (ηn-arene)M(L)X, (L = ethylenediamine or α-amino carboxylate), (M= Ir, Rh, Ru, Co). Arene, Ligand and metal center variations were designed to tailor antimicrobial activity specific for each organism studied (Staphylococcus aureus or Mycobacteria). Each of the D/L-amino acids formed a diasteromeric complex with chiral centers on both the metal center and amino acid ligand. The unique chirality of each center elicits different antimicrobial activity against the Mycobacteria studied. The metal center (M), arene ligand (ηn-arene), and amino acid (aa), were changed independently and studied for the antimicrobial activity. In a similar fashion, each of the complexes modified with ethylenediamine and diamine derivatives were studied for their antimicrobial activity against S.aureus. All complexes were synthesized,characterized by nuclear magnetic resonance (NMR), high-resolution mass spectroscopy (HRMS), single-crystal X-ray diffraction, and elemental analysis. During the course of this work it was found that the amino acid complexes with all metal centers were specific for antimicrobial activity against all types of Mycobacteria, while the diamine derivatives were active against different strains of S.aureus. Acitvity was measured to be as low as 2 ug/mL respectively depending on the complex used. A structure activity relationship was developed to determine what combinations of ligand, metal and arene were necessary to achieve the highest antimicrobial activity. The optimal arene R-chain length for CpR was determined to be R=hexyl for all complexes studied. The most active amino acidcomplex was determined to be that of L-phenylglycine for Mycobacteria, the cis-1,2-diaminocyclohexane complex is the most active ligand against S.aureus. Each metal center had similar activity levels. Toxicological studies were performed to test their viablity to be used in mammalian systems. The complexes with the highest activity were studied against several mammailan cell lines and revealed that mammailan cells were undergoing normal cellular processes at up to 40 times the minimal inhibitory concentration (MIC). A study of the MOA or mechanism of action revealed the ability of the amino acid complexes to affect the peptidyl transferase region on the 23s ribosomal subunit of M.smegmatis. This was accomplished by isolating resistant strains of M.smegmatis towards the most effective complex (Cp*hexyl)Ir(L-phenylglycine)-Cl. Cross drug resistance of these mutants was shown with clarithromycin. The DNA of the 23s ribosomal subunit was sequenced revealing a deletion/insertion mutation within domain V (bases 2057-2058). / Ph. D.

The oxidative addition of both monosubstituted and disubstituted a.-amino acids to [Ir(COD)(PMe3)3]Cl (COD = cyclooctadiene) was studied and the reactivity of the resulting complexes was examined. The reaction of [Ir(COD)(PMe3)3]CI with the disubstituted amino acids, diphenylglycine and methyl phenyl alanine, led to an almost exclusive facial product. Monosubstituted amino acid complexes were observed to be mixtures of the meridional and facial isomers with the meridional isomer largely predominating. The meridional isomer was found to convert to the facial isomer when heated for several days at 100°C. In fact, a predominantly meridional mixture was found to convert to a predominantly facial mixture upon heating. The facial isomer was therefore shown to be the thermodynamic product from the mixture. Small amounts of other isomers were observed in the hydride region of the proton NMR spectrum. One resonance at -23.75 ppm disappeared upon heating t-butyl acetylene with the amino acid complex. The disappearance of this hydride resonance may indicate the insertion of the unsaturate into the Ir-H bond, or alternatively, the conversion of this isomer to a more thermodynamically stable isomer. Reactions of these complexes with methylpropiolate and acrylamide were attempted but evidence of an insertion product was not found. / Master of Science

Polypyridyl transition metal complexes containing ruthenium, rhodium and iridium centers are mainly studied due to their light absorbing and emitting properties. Lanthanide oxides such as europium oxide absorb light as well and exhibit strong luminescence and long lifetimes. The optical properties of these materials were significant especially in solar energy utilization schemes and optical applications. Energy transfer across a surface is important in several applications including phosphors and biomedical applications. Excited states of metal complexes with a carboxylate-containing ligand such as deeb = diethyl-2,2'-bipyridine-4,4'-dicarboxylate were studied on nanoparticle surfaces. In this work, [Rh(deeb)2Cl2](PF6), [Ir(deeb)2Cl2](PF6) and [Ir(deeb)2(dpp)](PF6)3 were synthesized using the building block approach. The metal complexes were characterized using 1H NMR spectroscopy, mass spectrometry, electronic absorption spectroscopy and electrochemistry. The 1H NMR spectra of the complexes were consistent with those of their ruthenium analogs. Mass spectra contain fragmentation patterns of the (M-PF6)+ molecular ion for [Rh(deeb)2Cl2](PF6) and [Ir(deeb)2Cl2](PF6), and (M-3PF6)3+ molecular ions for [Ir(deeb)2(dpp)](PF6)3. The electronic absorption spectrum of [Rh(deeb)2Cl2](PF6) shows a maximum at 328 nm, which is assigned as 1π→π*transition. The electronic absorption spectrum of [Ir(deeb)2Cl2](PF6) shows maxima at 308 nm and 402 nm, which are assigned as 1π→π* and metal-to-ligand charge transfer transitions, respectively. The [Ir(deeb)2(dpp)](PF6)3 complex exhibits peaks due to 1π→π* transitions at 322 nm and 334 nm. [Rh(deeb)2Cl2](PF6) has emission maxima from the 3LF state at 680 nm and 704 nm for the solid and glassy solutions at 77 K, respectively. [Ir(deeb)2Cl2](PF6) has emission maxima from the 3MLCT state at 538 nm in acetonitrile and 567 nm in the solid state at room temperature, with lifetimes of 1.71 μs and 0.35 μs, respectively. [Ir(deeb)2Cl2](PF6) has an unusually higher quantum yield than analogous compounds. [Ir(deeb)2(dpp)](PF6)3 has emission maxima from the 3IL state at 540 nm in acetonitrile and 599 nm in the solid state at room temperature, with lifetimes of 1.23 μs and 0.14 μs, respectively. Cyclic voltammetry of [Ir(deeb)2Cl2](PF6) and [Ir(deeb)2(dpp)](PF6)3 yield reversible and quasi-reversible couples corresponding to deeb ligand and Ir3+/+reductions, respectively. Attachment of the complexes were conducted by equilibration of complex solutions in acetonitrile with europium oxide nanoparticles. Europium oxide nanoparticles, which were synthesized by gas-phase condensation, have 11-nm diameters and exhibit sharp f-based luminescence in the visible and near IR regions. EDX, TEM, IR and reflectance spectroscopy measurements indicate substantial coating through various modes of attachment of the nanoparticle surface by the metal complexes while retaining the excited state properties of the metal complexes. Surface adsorption studies indicate monolayer coverage of the nanoparticle surface by the metal complexes, consistent with limiting surface coverages of previously reported analogous systems. Eu2O3 nanoparticles modified with [Rh(deeb)2Cl2]+ exhibit minimal to no energy transfer from emission spectra, and a reduction in the lifetime at 77K could be due to the rhodium complex preventing the excitation of Eu3+. Upon attachment of the Ir complexes [Ir(deeb)2Cl2]+ and [Ir(deeb)2(dpp)]3+ on as-prepared nanoparticles, Eu3+ luminescence was observed for nanoparticles modified with iridium complexes at room temperature, which could be due to energy transfer among other possibilities. Efficiencies of 68% and 50%, and energy transfer rate constants of 1.1 x 10-5 and 1.0 x 10-5 were calculated from lifetime data for [Ir(deeb)2Cl2]+ and [Ir(deeb)2(dpp)]3+ on Eu2O3 nanoparticles, respectively. Since iridium complexes are used as components of light-emitting diodes, europium oxide nanoparticles modified with iridium complexes have potential in optical applications which make studies of these compounds interesting. / Master of Science

Grâce aux progrès réalisés ces dernières années dans la conception de réseaux intelligents, tels que les réseaux centrés sur la personne (WBAN) ou les réseaux sans fils de proximité (WPAN), de nouveaux types d’applications émergent et utilisent des capteurs d’informations capables de relever les paramètres physiologiques, environnementaux et plus particulièrement le positionnement des personnes. Dans ce cadre, nous nous sommes attachés dans ce travail de recherche à la conception et la réalisation d’antennes en polarisation circulaire pouvant être intégrées dans des vêtements, pour les standards de géolocalisation européen Galiléo et Américain GPS. Nous avons utilisé pour ces antennes des structures métamatériaux de type conducteurs magnétiques artificiels, afin d’augmenter les performances en rayonnement et pour diminuer le couplage avec et le corps humain. Une autre voie explorée est l’utilisation d’antennes patchs qui sont de nature faible encombrement. La bande de fréquence du standard de communications par satellite Iridium étant très proche du standard de géolocalisation GPS, nous avons trouvé intéressant de développer une solution de type patch couvrant les deux bandes GPS (1,575 GHz) et Iridium (1,621 GHz). L’antenne devant être intégrée sur une boite crânienne, les niveaux de débit d’absorption spécifique et les modifications du rayonnement sous conformation de l’antenne ont également été étudiés. L’évolution de ce travail a été ensuite d’étudier le comportement de cette antenne posée sur le dessus d’un casque militaire français. Les performances en rayonnement ont été satisfaisantes et ont montré la possibilité d’une telle application. / Thanks to the progress made in the recent years in the design of smart networks, such as wireless Body Area Network (WBAN), or Wireless Personal Area Network (WPAN), a novel type of emerging applications using smarts sensor measuring physiologic parameters, environmental et more particularly positioning of the persons are nowadays available. In the research presented in this manuscript, we are committed to design and realize antennas that can be possibly integrated into clothes, dedicated to the American GPS (1.227 GHz - 1.575 GHz) and European Galileo (1.180 GHz - 1.575 GHz) global navigation satellite systems. We used for these antennas a type of metamaterial structure named artificial magnetic conductor, to increase and enhance the radiation performance and reduce the coupling between the antenna and the human body. Another way has been explored using patch antenna solutions that are inherently low profile antennas. As the frequency band of the satellite communication system Iridium is close to the GPS one, we developed a dual band antenna solution covering both GPS (1.575 GHz) and Iridium (1.612 GHz) standards. The antenna being dedicated to be integrated over a human skull, the specific absorption rate and the radiation modification was also studied.