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Transition metals have been used to mediate bioorthogonal reactions within a biological environment. In particular, applications of biocompatible palladium catalysis currently range from biomolecules modification to the in cellulo synthesis or activation of drugs. Here, the scope of palladium-mediated chemistry in living systems has been further extended with the development of a new homogenous palladium catalyst. This water-soluble, biocompatible, and traceable catalysts is based on a palladium-carbene complex coupled to a fluorescent labelled homing peptide for targeted delivery inside cells. This “SMART” catalyst is designed to activate both caged fluorophores and drugs through the cleavage of protecting groups or cross-coupling reactions. A second strategy for targeted delivery of a biocompatible palladium catalysis involves metal nanoparticles loaded onto a heterogeneous solid support. This “modular” catalyst can be implanted in vivo at the desired site of action, e.g. a tumour, and locally activate biomolecules. These two catalytic systems will allow us to selectively activate pro-drugs in vivo, with spatial control, thus minimising the side effects of the treatment on the whole body.

Since the discovery that diazomethane, CH2N2, can effect the cyclopropanation of alkenes under palladium catalysis in the 1960s, this reaction has been used to great effect in synthesis. However, the necessity of preparing and handling diazomethane, a toxic and explosive reagent, is unappealing. The substitution of diazomethane for a commercially-available and thermally-stable silylated congener, namely trimethylsilyldiazomethane (TMSDAM), has been investigated. Under optimised conditions, designed to promote protodesilylation, use of this reagent affords the same products as would be obtained with the more hazardous diazomethane, with no trace of the corresponding silylated cyclopropanes. NMR spectroscopy has revealed that the protodesilylating agent employed in the reaction, tetrabutylammonium bifluoride (n-Bu4N+ HF2 -, TBABF), reacts cleanly with TMSDAM to generate diazomethane. Under catalytic conditions, the consumption of the desilylated diazo reagent by palladium is sufficiently rapid to prevent the accumulation of this hazardous reagent in solution. Spectroscopic titration studies also revealed a “hidden” mode of TBABF catalysis, whereby adventitious water drives the regeneration of the bifluoride salt. This observation was exploited by the development of an EtOH-driven reaction variant in which catalytic amounts (20 mol%) of TBABF could be employed. The ability to effect the in situ generation of diazomethane has allowed for mechanistic studies into the course of the cyclopropanation reaction to be undertaken. These reveal a partitioning in the consumption of nascent diazomethane between the desired cyclopropanation reaction and a side reaction. The product of the side reaction was identified as cyclopropane (C3H6), the product of formal methylene cyclotrimerisation, by employing EtOD in TBABF-catalysed deuterodesilylative cyclopropanation. The partitioning between the two pathways is dependent on the nature of the substrate, with efficient cyclopropanation dominating with electrondeficient alkenes. For an electronically-varied range of styrenes, the relative rate of productive diazomethane consumption correlates well with the energy of the frontier molecular orbitals (as determined by DFT calculations). These results are consistent with an initial, substrate-dependent partitioning of the palladium pre-catalyst between species able to effect alkene cyclopropanation, and those (likely higher-order) species which promote only the cyclotrimerisation of diazomethane.

Esta tesis se ha centrado en el estudio de las reacciones de carbonilación de norborneno catalizada por metales. Este sustrato puede ser funcionalizado a través de este proceso, empleando sistemas catalíticos y condiciones de reacción adecuadas, en productos intermedios con aplicación en la industria de perfumes y química fina. En este trabajo se han llevado a cabo estudios en la reacción de metoxicarbonilación de norborneno catalizada por paladio empleando ligandos monofosfina y difosfina logrando un importante control de la selectividad hacia la formación del producto deseado. Algunos aspectos mecanísticos de esta reacción han sido desarrollados empleando métodos de resonancia magnética nuclear que incluyen experimentos de alta presión. Finalmente, se ha estudiado la reacción de hidroformilación asimétrica de norborneno catalizada por complejos de rodio usando ligandos difosfito derivados de carbohidrato. Estos sistemas catalíticos han mostrado alta actividad y selectividad con excesos enantioméricos moderados. / This thesis focuses on the study of the metal-catalyzed carbonylation of norbornene. The transformation of this substrate in esters and aldehydes offers potential applications for the production of valuable compounds in fine chemistry and perfumery industry. In this work we have performed studies on the palladium-catalyzed methoxycarbonylation of norbornene bearing monodentate and bidentate phosphine ligands achieving an important control of the selectivity towards the formation of the desired product. Mechanistic aspects of this reaction have been developed using nuclear magnetic resonance methods, including High-Pressure techniques. Finally, we have studied the asymmetric rhodium-catalyzed hydroformylation of norbornene using chiral 1,3-diphosphites ligands derived from carbohydrates. These catalytic systems have shown high activities with excellent stereoselectivities and moderate enantioselectivities.

M. Tech. (Department of Chemical Engineering, Faculty of Engineering and Technology): Vaal University of Technology / The arylation and alkenylation of alkenes under the influence of a palladium catalyst, commonly referred to as the Heck reaction, has been extensively exploited by synthetic chemists since its debut in the late 1960’s. A traditional Heck coupling is based on an aryl iodide or bromide as the electrophilic partner and a terminal alkene as the nucleophilic partner. Academic and industrial interest in this reaction has increased in recent years, fueled by the development of more active catalyst systems, the discovery of waste-free versions, and the desire to put the vast empirical data on a sound mechanistic basis. In this study, we wish to report the use of commercially available substituted pyrazolones (1-(4-Sulfophenyl)-3-methyl-5-pyrazolone (L1), 1-(2,5-Dicloro-4-sulfophenyl)-3-methyl-5-pyrazolone (L2) and 5-oxo-1-phenyl-2-pyrazolin-3-carboxylic acid (L3)) and pyrazoles (α-[(2-Ethoxy-2-oxoethoxy)imino]-3-pyrazole acetic acid (L4) and 3.5 dimethyl pyrazole (L5)) as auxiliary ligands in the Heck coupling reaction. These ligands were used either with PdCl2 or Pd(OAc)2 to catalyze the Heck reaction of iodobenzene with ethyl acrylate or butyl acrylate. GC-MS was used to monitor the reaction, percentage (%) conversions were determined based on the consumption of iodobenzene. Different reaction parameters such as ligands, temperature, base, solvent and influence of time were investigated. It was observed that the lower conversion was obtained for ethyl acrylate and conversions above 80% were obtained for butyl acrylate. Ligand effect proved to be very crucial during the Heck coupling reactions of iodobenzene with butyl acrylate and ethyl acrylate. For instance in the absence of ligands with PdCl2, the conversions were 29 % and 44 % for butyl acrylate and ethyl acrylate, respectively. When Pd(OAc)2 was used in the absence of ligands the conversions were 25 % and 36 % for butyl acrylate and ethyl acrylate, respectively. In the study for the effect of temperature, 80 ◦C was observed as the best temperature since promising conversions were obtained with little or no sign of deactivation of the catalysts. On the other hand, increasing the temperature to 120 ◦C and above high percent conversions are observed; however deactivation of the catalysts occurs as observed from the precipitation of palladium black at the bottom of the vial. From the results obtained it is clear that pyrazolone and pyrazole ligands/palladium systems are important at very low catalyst loadings and mild temperatures. Based on the employed reaction conditions the influence of base suggested that the organic base triethylamine was the reagent of choice since better conversions were obtained compared to inorganic bases. The inhomogeneity of the inorganic base proved to be a disadvantage in the reaction of iodobenzene with butyl acrylate at employed reaction conditions. It was also found that parameters such as solvents and time effects were important in the Heck reaction. Polar aprotic solvents proved to be solvents of choice rather than non-polar solvents, from the investigated solvents DMF gave better conversions under the used reaction conditions giving average conversions of 78 % and 75 % for all the ligands in the presence of PdCl2 and Pd(OAc)2, respectively. During the investigation of time effect, it was noteworthy to observe that L4 had a slow initiation rate, for instance after 0.5 h conversions of 2 % and 10 % were obtained for catalytic systems, PdCl2 and Pd(OAc)2 respectively. Also it was observed that under the investigated parameters there was no need to run the reaction for 24 h because after 4 h not much of a difference in conversions was observed. In comparing the influence of these two different auxiliary ligands, pyrazolone based ligands were more efficient than pyrazole based ligands under the investigated parameters. The fully detailed information supporting this has been discussed in Chapter 4.

N-phenylpyridin-2-amine , treated with stochiometric amount of palladium(II) acetate in dichloromethane at 65-70¢J for 4 h, to give high yield palladacycle 53. The reaction of palladacycle 53 with potassium aryltrifluoroborates in 1,4-dioxane at 140¢J for 24 h, could give a variety of N-(2-pyridinyl)carbazoles 55a-55m via sequential C-H bond activation. Carbazole derivative 55a reacted with irdium chloride gave iridium dimer, which followed by addition of picolinic acid via ligand exchange will form iridium complexes, which can further be utilized as OLEDs materials.

Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第16808号 / 工博第3529号 / 新制||工||1534(附属図書館) / 29483 / 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 村上 正浩, 教授 吉田 潤一 / 学位規則第4条第1項該当

Title: Controllable synthesis, treatment and characterization of anodes for Direct Formic Acid Fuell Cell Author: Mgr. Igor Bieloshapka Department/Institute: Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University Supervisor of the doctoral thesis: Ing. Petr Jiříček, CSc., Institute of Physics of the Czech Academy of Sciences, Division of Solid State Physics, Department of Optical Materials Abstract: At this doctoral thesis, anodes were prepared by novel DC magnetron sputtering technique for direct formic acid fuel cells (DFAFCs). Anode part consisted of support material and catalyst. Carbon cloth and polyaniline were used as a support. Palladium and palladium-copper bimetallic catalysts were deposited on the top of the support. Scanning electron microscope (SEM) and atomic force microscope (AFM) were used for investigation of the morphology of the anodes. Composition and chemical states on the anode part were studied by x-ray photoelectron spectroscopy (XPS). Transmission electron microscope (TEM) together with the XPS technique were used for characterizing graphene oxide (GO) and reduced graphene oxide (RGO) as a promising support for the polymer membrane fuel cells. For decreasing the role of substoichiometric PdCx phase and other contaminations on the surface of...

Title: Controllable synthesis, treatment, and characterization of anodes for Direct Formic Acid Fuel Cell Author: Igor Bieloshapka Department: Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University Supervisor of the doctoral thesis: Ing. Petr Jiříček, CSc., Institute of Physics of the Czech Academy of Sciences, Division of Solid State Physics, Department of Optical Materials Abstract: This doctoral thesis concerns the preparation of anodes with Pd-based catalysts. Anodes were deposited on a support surface with magnetron sputtering. The prepared samples were tested in a direct formic acid fuel cell (DFAFC) station. Polyaniline, graphene oxide (GO) and reduced graphene oxide (RGO) have been additionally investigated as promising support material for polymer membrane fuel cells (FCs). A scanning electron microscope (SEM) and a transmission electron microscope (TEM) were used to observe the morphological differences between the prepared samples. Elemental composition and chemical states on the anode part were studied through X-ray photoelectron spectroscopy (XPS). The results show that the power density of the prepared anodes with 3 nm of palladium thickness is lower only by 30% in comparison with chemically prepared catalysts. The highest power density results were achieved for the...

Size-selected Pd nanoparticles were synthesized by the reverse-micelle encapsulation method and deposited on a ZrO2 support for the catalytic NO reduction by H2. All of our samples were found to be highly selective, but a significant size effect was not seen for Pd nanoparticles of between 1.2 nm and 5.5 nm. Ultra-small Pd clusters of less than 1 nm were found to be much less active, and are assumed to be affected by an encapsulation effect of the support. Catalyst activity was comparable to that of literature, and is applicable to H2-SCR research.