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  • Publication
    Accès libre
    Thiolato-bridged arene ruthenium complexes as anticancer agents
    (2015)
    Stíbal, David
    ;
    Cancer is a major cause of morbidity and mortality in today’s world, affecting populations in all countries and all regions. Although no drug or treatment able to cure cancer in all of its forms and variations was found so far, the clinical advancements of 20th and 21st century provided a number of effective drugs for specific types of cancers and had a significant effect on the survival and the quality of life of patients. One of these drugs, the platinum-based complex cisplatin, achieved almost 100% cure rate of testicular cancer, not only saving lives of thousands of patients every year but also overturning a paradigm of medicinal chemistry – it was the first metal-based anticancer drug used in the clinic. The success of cisplatin encouraged the search for new metal-based anticancer agents, which soon expanded to other metals, such as ruthenium. During the last three decades, numerous ruthenium-based compounds with interesting anticancer properties were prepared and thoroughly investigated, two of which (NAMI-A and KP1019) were ultimately introduced into clinical trials, showing the potential of ruthenium complexes in cancer therapy.
    The goal of the presented thesis was to investigate the properties of dinuclear arene ruthenium thiolato-bridged complexes and to establish their potential as anticancer drugs. In the first part of the thesis, several monothiolato, dithiolato and trithiolato complexes were synthesized and evaluated for their stability and reactivity with biological substrates. The results were correlated with the in vitro anticancer activity of the three types of complexes and showed the most stable trithiolato complexes to be the most active against ovarian cancer cell lines. Subsequently, the most active trithiolato derivative, diruthenium-1, was thoroughly investigated in vitro and in vivo to establish the mode of action of this complex, showing its promising ability to influence the tumor growth and to prolong the survival of tumor-bearing mice.
    In the second part of this thesis, three series of conjugates of the mixed trithiolato complexes were synthesized to demonstrate the potential of the coupling of dinuclear arene ruthenium complexes with biologically active organic molecules. Thus, the thiolato-bridged complexes were coupled with propargyl bromide, the resulting conjugates being available for the 1,3-Huisgen addition with tumor targeting compounds. Conjugates with ibuprofen were synthesized to investigate the effect of the antiinflamatory agent on the activity and selectivity of the resulting complexes towards cancer cells. Finally, conjugates of dinuclear trithiolato arene ruthenium complexes with alkylating agent chlorambucil were synthesized to show the effect of the two different modes of action of the conjugates on their activity in vitro and in vivo.
    These results demonstrate the potential of the dinuclear thiolato-bridged arene ruthenium complexes as a versatile platform for the synthesis of anticancer agents with variable biological properties and modes of action.
  • Publication
    Accès libre
    Metallic ruthenium nanoparticles derived from arene ruthenium complexes: synthesis, characterization and applications
    (2012)
    Khan, Farooq-Ahmad
    ;

    The present work deals with the preparation of ruthenium nanoparticles using an organometallic approach. In the first part, the synthesis of ruthenium nanoparticles stabilized by mesogenic isonicotinic ester ligands is presented. We have been interested in the use of long-chain isonicotinic esters as lipohilic components in order to increase the anticancer activity of arene ruthenium complexes, while using them as stabilizers for ruthenium nanoparticles with the aim of exploring self-organization and biological (anticancer) properties of these new hybrid materials. The ruthenium nanoparticles thus obtained as well as their organometallic precursors showed anticancer activity comparable to cisplatin or superior to cisplatin in the cancer cell lines A2780 and cisplatin-resistant cell line A2780cisR, the highest cytotoxicity being 0.179 µM, a value 9 fold lower than cisplatin – a platinum-based chemotherapy drug widely used to treat different types of cancers.

    In second part, silicate-supported ruthenium nanoparticles with a special emphasis on hectorite-supported Ru(0) is presented. Size- and shape-selective preparation of hectorite-supported ruthenium nanoparticles was achieved by using either molecular hydrogen or solvothermal reduction route employing different organometallic precursors. The catalytic efficiency of these nanoparticles was evaluated for different arenes, furfuryl alcohol and α,β-unsaturated ketones. Hectorite-supported ruthenium nanoparticles were found to be promising hydrogenation catalysts. It was observed that the modification of intercalated particles size and reaction conditions tune the catalytic activity for chemo-selective reactions. Thus, these nanoparticles preferentially reduce the C=C olefinic bond in α,β-unsaturated ketones at 35 °C. However, change in particle size results in high selectivity towards C=O bond of α,β-unsaturated ketones, if an excess of solvent is used at low temperatures. A selectivity > 98 % for an unconstrained α,β-unsaturated ketone, trans-4-phenyl-3-penten-2-one, was observed at 0 °C. This kind of selectivity is unique for a heterogeneous catalyst especially when the C=C olefinic bond in α, β-unsaturated moiety is sterically not hindered. It was believed that such a preferential C=O bond hydrogenation in α,β-unsaturated ketones was not possible with heterogeneous catalysts.

    In the last part, superparamagnetic core-shell-type Fe3O4/Ru nanoparticles (particle size ~ 15 nm), synthesized by co-precipitation, adsorption and reduction methods, are presented. Their catalytic efficiency for selective C=O hydrogenation in an unconstrained α,β-unsaturated ketone was evaluated using <>trans-4-phenyl-3-penten-2-one. These particles present a green and sustainable approach towards catalyst separation from the reaction mixture, as they can be efficiently separated from the reaction mixture by applying an external magnetic field.

    It was the aim of this study to develop metallic ruthenium nanoparticles stabilized by mesogenic isonicotinic ester ligands, intercalated in hectorite and supported on magnetite and to evaluate their catalytic and biological potential.
  • Publication
    Accès libre
    Arene Ruthenium Assemblies for Biological Applications: From Carceplex to Host-Guest Metalla-Cages
    (2011)
    Barry, Nicolas
    ;
    ;
    Le développement depuis les années 1980 de la chimie supramoléculaire a permis la synthèse d’objets discrets toujours plus complexes. Le rôle des métaux a été prépondérant, grâce notamment à leur mode de coordination qui permet d’orienter de façon rationnelle l’organisation moléculaire au sein même de l’architecture supramoléculaire. Ainsi, les métalla-cages ont été au centre de l’attention des chimistes, de par leur facilité d’accès au niveau synthétique mais aussi de par leur large spectre d’utilisation.
    Depuis la mise sur le marché et le succès clinique du cisplatine comme agent antitumoral, les métaux de transition sont également particulièrement étudiés dans une telle optique d’application. Parmi les plus prometteurs, les complexes mononucléaires arène-ruthénium ont démontré un fort potentiel antiprolifératif tout en étant moins toxiques que les complexes de platine.
    Le but de cette thèse de doctorat était de combiner les propriétés d’assemblage des complexes arène-ruthénium en chimie supramoléculaire avec leurs propriétés antiprolifératives. Pour cela, plusieurs métalla-cages ont été construites ; leurs habilités à encapsuler de façon permanente ou réversible des molécules invitées ont été étudiées par différentes méthodes spectroscopiques, et les comportements antiprolifératifs des systèmes ainsi obtenus ont été établis in vitro envers différentes lignées de cellules cancéreuses., Since the development of supramolecular chemistry in the 1980s more and more discrete molecular objects have been synthesised. In this research area metals play a key role. Indeed, the coordination-driven self-assembly allows a directional-bonding approach that organises the different building blocks into supramolecular objects according to the coordination modes of the transition metal. Therefore, the versatility of metalla-cages and their application potential raised an increasing interest for this chemistry.
    On the other hand, ever since the clinical success of cisplatin as an antitumour drug, transition metals have raised considerable expectations for the treatment of cancer. So far, mononuclear arene ruthenium complexes are of central interest due to established cytotoxicity towards cancer cells and low general toxicity.
    The aim of this thesis was to combine the assembling properties of arene ruthenium complexes in supramolecular chemistry with their antiproliferative activity. Thus, different metalla-cages were synthesised, the permanent or reversible hosting ability of which was studied by various spectroscopic methods with different guest molecules. The antiproliferative behaviour of the resulting systems was established in vitro towards different cancer cell lines.