Current chemotherapeutics exhibit debilitating side effects as a result of their toxicity to healthy tissues. Reducing these side effects by developing chemotherapeutics with selectivity for cancer cells is an active area of research. Phototherapy is one promising modality for selective treatment, where drug molecules are “turned on” when irradiated with light, reducing damage to healthy tissues by spatially restricting the areas exposed to irradiation. A second approach to improve selectivity is to exploit the differences in cancerous versus healthy cells, such as increased metabolism and/or upregulation of cell surface receptors. Ruthenium(II) polypyridyl complexes are candidates for phototherapy due to their highly tunable photophysical and photochemical properties. The addition of strain to the metal center is a general approach used to render complexes susceptible to light-induced ligand loss. Upon ejection of a ligand, the Ru(II) center is capable of covalently binding biomolecules within cells to produce a cytotoxic effect. The ligands surrounding the metal center are amenable to chemical modification through the incorporation of pendent functional groups as chemical “handles”, allowing for different directing molecules to be attached. Nucleic acids are important targets for drug discovery, and the development of selective probes to either visualize or selectively damage nucleic acids within the cell is an ongoing area of research. Specifically, G-rich regions are abundant in the human genome, and the presence of G-quadruplexes in telomeres and promoter regions of oncogenes make them potential therapeutic targets. Ru(II) complexes are known to bind nucleic acids, and some have been shown to induce and/or stabilize G-quadruplex Structures. Multiple series of Ru(II) compounds have been synthesized and tested to improve the functional range for Ru(II) complexes for in vivo applications, where they act as “light switches” for DNA. These molecules are “off” when in an aqueous environment but turned “on” in the presence of DNA. Several hit compounds were identified that showed selectivity for specific G-quadruplex structures.

Metal-organic frameworks (MOFs) have been extensively studied because of their amazing applications in gas storage, purification, photocatalysis, chemical sensing, and imaging techniques. Ruthenium polypyridyl complexes have been broadly considered as photosensitizers for the conversion of solar energy and photoelectronic materials. With this aspect, we have synthesized three new ruthenium polypyridyl based MOFs ([Ru(H2bpc)Cu(bpc)(Hbpc)2(H2O)]·5H2O (1), [Ru(H2bpc)(Fe(bpc)(Hbpc)2(H2O)2]·6H2O (2) and [Ru(H2bpc)Ni(bpc)(Hbpc)2(H2O)2]·6H2O (3)) from ruthenium(III) chloride, bpc (2,2’- bipyridine-4,4’-dicarboxylic acid) ligand, and 3d M(II) metal ions (M(II)= Cu(II), Fe(II), Ni(II)). These MOFs were synthesized under hydro or solvothermal conditions by using water, ethanol or methanol as solvents. The crystal structures of the new compounds contains zigzag chains of [Ru(bpc)3]n- complex ions linked by Cu, Fe or Ni complex ions individually. Above synthesized crystal structures were characterizing by single-crystal Xray and powder X-ray diffraction strategies, UV-vis and IR spectroscopy. Thermal properties were determining by thermogravimetric analysis. Magnetic properties were also studied.

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Les complexes de ruthénium à ligand nitrosyle sont très connus pour posséder des propriétés photochromes qui résultent des changements de coordination du fragment Ru-NO sous irradiation à basse température. Ce phénomène comporte de nombreuses applications telles que le stockage optique de données. Ces complexes ont aussi la capacité de délivrer l'oxyde nitrique de manière photo-contrôlée. Cela présente un grand intérêt car NO est impliqué dans de très nombreuses réactions physiologiques. Cette thèse est consacrée à l'étude des facteurs qui influencent les propriétés photochromes et la photolibération de NO dans les complexes de nitrosyle de ruthénium avec des ligands pyridine ou bipyridine. Le premier chapitre de cette thèse se concentre sur une étude bibliographique approfondie. Dans le second chapitre, la synthèse et la caractérisation des complexes de nitrosyle de ruthénium avec des ligands pyridine de formule trans(X, NO)-[Ru(R-py)4XNO](PF6)2 (R-py = pyridine, 4-picoline, 3-picoline, 4-vinylpyridine, 3- carboxaldéhydepyridine et 4-chloropyridine, X= Cl, Br, I ou OH) sont étudiés. Dans le troisième chapitre, la synthèse et la caractérisation des complexes de ruthénium nitrosyle avec le ligand bipyridine de formule cis(X, NO)-[Ru(L)2XNO] Y2, (L= 2,2'-bipyridine ou 4,4'-diméthyl-2,2'-bipyridine, X= Cl, NO2 ou Br, Y= PF6 ou Br) sont discutés. Dans le quatrième chapitre, nous présentons les résultats sur l'étude de photoisomérisation des complexes présentés dans les chapitres précédents. La conversion Ru-NO/Ru-ON est estimée par spectroscopie infrarouge après irradiation par une lumière bleue à basse température à l'état solide. Le taux de population Ru-NO/Ru-ON varie entre 1 et 76%. Nous avons étudié les effets de la position cis/trans et de la nature du ligand par rapport au nitrosyle, des substituants (groupe donneur ou attracteur d'électrons) sur le ligand pyridine ou bipyridine sur la réponse photochrome. Des calculs théoriques par DFT ont permis de rendre compte des propriétés photochromes différentes entre le complexe parent avec un ligand pyridine et le ligand 4-chloropyridine. Le cinquième chapitre est consacré à l'étude de la photolibération de NO. Le rendement quantique (NO) se trouve dans la gamme 0.2-0.7. Le test de Griess a confirmé le relargage de NO. / We are interested in the photoactive properties of ruthenium nitrosyl complexes. Ruthenium nitrosyl complexes are well known to possess photochromic properties which arise from the coordination changes of Ru-NO under irradiation at low temperature. This phenomenon has many applications such as high optical data storage and sensors. Ruthenium nitrosyl complexes are also very promising candidates because the photochemical delivery of bioactive small molecules such as nitric oxide (NO•) from ruthenium nitrosyl complexes presents the possibility of controlling the location, timing and dosage of NO• to physiological targets. Nitric oxide photorelease have gained wide attention after the discovery of several nitric oxide physiological functions and its involvement in different cellular processes. This thesis was devoted to studying the factors which affect the photochromic properties and NO photorelease in ruthenium nitrosyl complexes with pyridyl or bipyridyl based ligands. The first chapter of this thesis focuses on a survey of the literature related to both photoisomerization and photorelease phenomena. In chapter 2, the synthesis and characterization of ruthenium nitrosyl complexes with pyridyl based ligands with the formula trans(X,NO)-[Ru(R-py)4XNO](PF6)2, (where R-py is pyridine, 4-picoline, 3-picoline, 4-vinylpyridine, 3-carboxaldhydepyridine and 4-chloropyridine, X=Cl, Br, I or OH) are discussed. In chapter 3, the synthesis and characterization of ruthenium nitrosyl complexes with bipyridyl based ligand with formula cis(X,NO)-[Ru(L)2XNO]Y2, (L= 2,2'-bipyridine or 4,4'-dimethyl-2,2'-bipyridine, X=Cl, NO2 or Br, Y=PF6 or Br) are discussed. In chapter 4, we present the results of our investigations of nitrosyl ligand photoisomerization in Ru-NO with pyridyl and bipyridyl ligands. The conversion of Ru-NO to Ru-ON conformation was estimated by infrared spectroscopy upon irradiation by blue light at low temperature in the solid state. The values are ranged between 1-76%. We studied the effects of cis/trans ligand position to nitrosyl and the nature of substituents on pyridine or bipyridine ligand (electron donating or withdrawing group). We used theoretical calculations (DFT) to explain the different photochromic properties between parent complex with a pyridine ligand and 4-chloropyridine ligand. The fifth chapter is devoted to the study of NO photorelease. The quantum yield (NO) was estimated in the range of 0.2-0.7. Griess test was used to confirm NO delivery.