Methane and dinitrogen are abundant precursors to numerous valuable chemicals such as methanol and ammonia, respectively. However, given the robustness of these substrates, catalytically circumventing the high temperatures and pressures required for such transformations has been a challenging task for chemists. In this work, computational studies of various transition metal catalysts for methane C-H activation and N2 activation have been carried out. For methane C-H activation, catalysts of the form LnM=E are studied, where Ln is the supporting ligand (dihydrophosphinoethane or β-diketiminate), E the activating ligand (O, NCH3, NCF3) at which C-H activation takes place, and M the late transition metal (Fe,Co,Ni,Cu). A hydrogen atom abstraction (HAA) / radical rebound (RR) mechanism is assumed for methane functionalization (CH4 à CH3EH). Since the best energetics are found for (β-diket)Ni=O and (β-diket)Cu=O catalysts, with or without CF3 substituents around the supporting ligand periphery, complete methane-to-methanol cycles were studied for such systems, for which N2O was used as oxygen atom transfer (OAT) reagent. Both monometallic and bimetallic OAT pathways are addressed. Monometallic Fe-N2 complexes of various supporting ligands (LnFe-N2) are studied at the beginning of the N2 activation chapter, where the effect of ligand on N2 activation in end-on vs. side-on N2 isomers is discussed. For (β-diket)Fe-N2 complexes, the additional influence of diketiminate donor atom (N(H) vs. S) is briefly addressed. The remainder of the chapter expands upon the treatment of β-diketiminate complexes. First, the activation and relative stabilities of side-bound and end-bound N2 isomers in monometallic ((β-diket)M-N2) and bimetallic ((β-diket)M-N2-M(β-diket)) first row transition metal complexes are addressed. Second, the thermodynamics of H/H+/H- addition to (β-diket)Fe-bound N2, followed by subsequent H additions up to release of ammonia, is discussed, for which two mechanisms (distal and alternating) are considered. Finally, the chapter concludes with partial distal and alternating mechanisms for H addition to N2 in bimetallic (β-diket)Fe-N2-Fe(β-diket) and (β-diket)M-N2-M(β-diket) (M = Ti,V,Fe), respectively.

Orientadores: Pedro Paulo Corbi, André Luiz Barboza Formiga / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-27T06:22:14Z (GMT). No. of bitstreams: 1 Carvalho_MarcosAlbertode_D.pdf: 4861042 bytes, checksum: 806502263c8b6f3d1f87f5ac3834609c (MD5) Previous issue date: 2015 / Resumo: O uso de metais em medicina, no tratamento de doenças, data desde a antiguidade. Sais de prata são utilizados há séculos como agentes antimicrobianos, enquanto que, mais recentemente, complexos de Au(I) e Pt(II) tem sido pesquisados e utilizados como agentes antiartríticos e antitumorais, respectivamente. Nesta Tese, são apresentados estudos de síntese, caracterização estrutural e ensaios biológicos in vitro de novos complexos metálicos de Pt(II), Pd(II), Ag(I) e Au(III) com diferentes ligantes bioativos: triptofano (Trp), triptamina (tra), ácido mefenâmico (mef) e carnosina (car). Os complexos foram preparados a partir da reação em solução aquosa ou alcoólica dos ligantes e dos respectivos sais metálicos. As composições dos complexos foram determinadas por análise elementar, espectrometria de massas e por análise termogravimétrica. Estudos espectroscópicos e de modelagem molecular permitiram propor os modos de coordenação dos ligantes aos íons metálicos. Os complexos de Ag(I) e Pd(II) com Trp mostraram atividade sobre cepas bacterianas Gram-negativas e Gram-positivas. O complexo de Pd(II) com triptamina não apresentou atividade frente as cepas de Escherichia coli, Pseudomonas aeruginosa e Staphylococcus aureus. O complexo de Pd(II) com ácido mefenâmico e bipiridina mostrou atividade inibitória frente a cepas de S. aureus e não foi ativo sobre E. coli e P. aeruginosa. Estudos de citotoxicidade dos complexos de Ag(I), Pd(II) e Pt(II) com Trp pela redução do MTT sobre as linhagens de células Balb/c3T3, SK-Mel 103 e Panc-1 mostraram que os complexos são citotóxicos para todas as linhagens consideradas / Abstract: The use of metals in medicine in the treatment of diseases dates since antiquity. Silver salts have been used as antimicrobial agents for centuries, while more recently, Au(I) and Pt(II) complexes have been investigated and used as antiarthritic and antitumor agents, respectively. This Thesis presents the synthesis, structural characterization and biological assays in vitro of new metal complexes of Ag(I), Pd(II), Pt(II) and Au(III) with the bioactive ligands tryptophan (Trp), tryptamine (tra), mefenamic acid (mef) and carnosine (car). The complexes were prepared by the reaction of the ligands and metal salts in aqueous or alcoholic solutions. Composition of complexes were determined by elemental analysis, mass spectrometry and thermogravimetric analyses. Spectroscopic and molecular modeling studies were used to determine the coordination modes of the ligands to the metals. Complexes of Ag(I) and Pd(II) with Trp showed activity against Gram-positive and Gram-negative strains. The Pd(II) complex with tryptamine showed no activity against Escherichia coli, Pseudomonas aeruginosa ande Staphylococcus aureus strains. The Pd(II) complex with mefenamic acid and bipyridine showed inhibitory activity against S. aureus strains and it was not active on E. coli and P. aeruginosa. Cytotoxicity studies of the Ag(I), Pd(II) and Pt(II) complexes with Trp by MTT reduction on Balb/c3T3, SK-Mel 103 and Panc-1 lines cells showed that complexes are cytotoxic to all considered cells / Doutorado / Quimica Inorganica / Doutor em Ciências

De nombreux complexes de Fe(TAML) ont été décrits au cours des dernières années. Notre groupe a étudié l’utilisation du complexe Fe(TAML-Me2) pour l’oxydation de liaisons C-H benzyliques. L'un des objectifs de cette thèse était de fonctionnaliser le complexe Fe (TAML-Me2) à différentes fins.L'une des fonctionnalisations consistait à utiliser un triazole substitué par une chaîne hexyle, qui pourrait influencer les propriétés physicochimiques du complexe de fer et qui pourraient être utilisées en catalyse homogène. Inversement, un TAML fonctionnalise par 1 triethoxysilane a été conçu pour être greffé sur un support inorganique pour une utilisation ultérieure en catalyse hétérogène. Enfin, une fonctionnalisation par une queue fluorée devai permettre était d'augmenter la solubilité du complexe dans les solvants fluorés en vue d'une utilisation potentielle dans un mélange biphasique susceptible de favoriser la recyclabilité du catalyseur.Nous avons révélé que le complexe MnII (Me2EBC)Cl2 pouvait catalyser l'oxydation d'une série d'alcools benzyliques et aliphatiques avec H2O2. Les conversions des alcools en composés carbonylés correspondants ont atteint 98% avec une sélectivité bonne à excellente / Fe(TAML) complexes have been investigated a lot in recent years. Our group has investigated the simplest Fe(TAML) catalyst for its oxidation with high efficiency. The purpose of this thesis was to functionalize the complex Fe(TAML-Me2) for different uses.One of the functionalizations was to have a hexyl-substituted triazole “tail”, which could influence the physicochemical properties of the iron complex in homogeneous catalysis. Conversely, a silicon tailed-one was designed to be grafted on an inorganic support for a use in heterogeneous catalysis. At last, the purpose of the fluorinated tail was to increase the solubility of the metallocomplex in fluorinated solvents for a potential use in a biphasic mixture that could favor the recyclability of the catalyst. The other purpose of the thesis was to develop an environmental benign catalytic oxidation system with a bioinspired catalyst MnII(Me2EBC)Cl2. We disclosed that the MnII(Me2EBC)Cl2 complex could catalyze the oxidation of a series of benzylic and aliphatic alcohols with H2O2. Conversions of the alcohols to corresponding carbonyl compounds reached 98% with good to excellent selectivity

Our country continues to demand clean renewable energy to meet the growing energy needs of our time. Thus, natural gas, which is 87% by volume of methane, has become a hot topic of discussion because it is a clean burning fuel. However, the transportation of methane is not easy because it is a gas at standard temperature and pressure. The usage of transition metals for the conversion of small organic species like methane into a liquid has been a longstanding practice in stoichiometric chemistry. Nonetheless, the current two-step process takes place at a high temperature and pressure for the conversion of methane and steam to methanol via CO + H2 (syngas). The direct oxidation of methane (CH4) into methanol (CH3OH) via homogeneous catalysis is of interest if the system can operate at standard pressure and a temperature less than 250 C. Methane is an inert gas due to the high C-H bond dissociation energy (BDE) of 105 kcal/mol. This dissertation discusses a series of computational investigations of oxy-insertion pathways to understand the essential chemistry behind the functionalization of methane via the use of homogeneous transition metal catalysis. The methane to methanol (MTM) catalytic cycle is made up of two key steps: (1) C-H activation by a metal-methoxy complex, (2) the insertion of oxygen into the metal−methyl bond (oxy-insertion). While, the first step (C-H activation) has been well studied, the second step has been less studied. Thus, this dissertation focuses on oxy-insertion via a two-step mechanism, oxygen-atom transfer (OAT) and methyl migration, utilizing transition metal complexes known to activate small organic species (e.g., PtII and PdII complexes). This research seeks to guide experimental investigations, and probe the role that metal charge and coordination number play.

Molecular self-assembly or ligand-metal assembly is a process in which several individual molecules and metal ions organize themselves into an ordered arrangement without external stimuli, the defined structures can lead to distinctive electronic and photonic performances. In the meantime, as the scale of materials decreases, various unique properties arise from their minute scaled dimensions, such as surface effect, volume effect, quantum effect and dielectric confinement effect, etc. Therefore, the design and fabrication of the micro- and nanomaterial via the technique of molecular self-assembly or ligand-metal assembly is becoming an emerging research field, for the purpose of meeting the increased demands of multi-functional materials. Chapter 1 gives an overview of the advanced materials prepared by either molecular self-assembly or ligand-metal assembly. We described the interaction nature in detail, and enumerated the applications as well as developments of this scientific field. Furthermore, the detailed classifications as well as previous work of these advanced materials we researched on, such as two dimensional nanosheets, hetero-structured materials and cyclometalated iridium(Ⅲ) complexes were also amply summarized. Two-dimensional nanosheets have always been a research hotspot since graphene was discovered and isolated. In contrast, molecule-based organometallic nanosheets through bottom-up method exhibit more inner structures. In Chapter 2, we constructed two classes of organometallic nanosheets with different intermolecular forces, one is metal-ligand coordination, while the other one is the aromatic (π-π) interaction. Two-dimensional nanosheets with Hg-acetylide linkages, bis(dipyrrinato)metal linkages as well as bis(terpyridine)metal linkages were synthesized and characterized by UV-Vis absorption spectroscopy, FT-IR spectroscopy, optical and electron microscopy, photoluminescence spectroscopy, thermal gravimetric analysis, X-ray photoelectron spectroscopy and so on. In addition, the potential applications were explored as well, including the tests of charge mobility and current capacitance. Meanwhile we also investigated the two-dimensional nanosheets self-assembled by aromatic (π-π) interaction. The morphology characterizations, crystal form measurements, besides elemental analyses were conducted. By means of surface control, the hybrid nanosheets could achieve many superior performances, like super hydrophobicity, high conductivity and soft magnetism. In Chapter 3, we firstly mentioned that organic hetero-structured micro- or nanomaterials are widely attractive on account of its extensive applications in lasers, bipolar transistors, field effect transistors and solar cells. In our work, we focus on the diverse microrods assembled from π-conjugated small molecules, especially in the construction of heterogeneous organic heterojunction materials with specific components distribution. Two novel kinds of heterostructure, multilayer core-shell structured heterojunction and heterogeneous rod-tail helix were fabricated and developed both via a stepwise seeded-growth route, in which the different constituents possess different colors of luminescence. Through the media of fluorescence microscopy and confocal microscopy, the core-shell hetero- structures can be observed, testified and recorded quite distinctly. Furthermore, the prepared method by employing seeded-precursor could give us a revelation about constructing more sophisticated and functional organic luminescent heterogeneous materials. Chapter 4 focuses on the syntheses and characterization of eight cyclometalated iridium(Ⅲ) complexes, Ir(TPY)2(Dipyrrinato), Ir(PIQ)2(Dipyrrinato), Ir(Ligand 1)2(Dipyrrinato), Ir(Ligand 2)2(Dipyrrinato), Ir(Ligand 3)2(Dipyrrinato), Ir(PPY)2 (Dipyrrinato), Ir(m-PPY)2(Dipyrrinato) and Ir(PPY-m)2(Dipyrrinato). As is known, iridium(Ⅲ) complexes can exploit the energy of both 25% singlet and 75% triplet excited states. Due to their highly efficient applications in phosphorescent OLEDs, these materials are considered as one of the potential candidates for flexible display screen as well as clearing luminary. Among those full-color light-emitting iridium(Ⅲ) phosphors, near-infrared (NIR) phosphors are broadly utilized in phototherapy as well as biosensors. Herein, our eight synthetic cyclometalated iridium(Ⅲ) complexes all gave photoluminescence at 680 - 700 nm in solution, which could be attributed to the NIR region. We continuously tune the extensive conjugation on the C^N ligands in order to make longer wavelength emitting phosphors. The HOMO and LUMO of eight synthetic iridium(Ⅲ) phosphors were also calculated according to their cyclic voltamograms (CV). The design and preparation strategy in this thesis can inspire us to develop near-infrared as well as higher-performance organometallic phosphors.

The kinetics of ligand substitution for CO in Co4(CO)10(mu4-PPh2) , 1, have been investigated for the ligands P(OMe)3, P(OEt)3, PPh2H, P(0-i-Pr)3, P(n-Bu)3, PPh3, P(i-Pr)3, and PCy3 over a wide temperature range.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21120号 / 工博第4484号 / 新制||工||1697(附属図書館) / 京都大学大学院工学研究科物質エネルギー化学専攻 / (主査)教授 大江 浩一, 教授 辻 康之, 教授 中尾 佳亮 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

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There is an urgent need to find novel anticancer therapeutics with different mechanisms of action than platinum-containing drugs, particularly for patients who relapse after having been initially treated with a platinum-containing chemotherapy regimen. This chemoresistance phenomena, along with the serious side effects observed with cisplatin, have led research in Medicinal Inorganic Chemistry to using other precious metals for the design of novel anticancer therapeutics. This work reports on the synthesis and characterisation of a series of organometallic drug candidates based on ruthenium, osmium, rhodium, and iridium, followed by investigation of their cancer-inhibiting properties via in vitro and in vivo studies. The cytotoxicity of these complexes against various human cancer cell lines is presented, as well as preliminary studies on their possible modes of action, determined via gene expression studies, cell cycle and apoptosis analysis, reactive oxygen species detection and mitochondrial-membrane potential assays. In addition, to confirm the surprising absence of in vitro toxicity against normal cells exhibited by some compounds, studies on ex vivo/in vitro isolated human lymphocytes from healthy individuals, have been conducted. One lead molecule has been progressed to in vivo studies in mice and toxicity and efficacy were assessed with a series of assays including determination of the maximum tolerated dose and pharmacodynamic studies. Structural modifications of the lead molecule with water-soluble phosphines were subsequently undertaken, with the aim to improve the stability and solubility of the parent 16-electron specie, and evaluations of the biological activity of these novel complexes are presented.