Neste trabalho, descreve-se a síntese, caracterização e propriedades dos complexos derivados da tetra(3,4-piridil)porfirazina com os grupos [Ru(bipy)2Cl]1+. A conjugação eletrônica entre o resíduo piridínico e o anel da porfirazina promovem uma eficiente comunicação entre os grupos periféricos e o central, que é refletido no espectro de emissão e seu correspondente perfil de excitação. Esse tipo de comportamento revela um efeito antena no sistema H2TPyPzTRu, contrastante com as propriedades fotofisicas das porfirinas análogas TPyPRu, onde os grupos piridínicos exibem baixa interação eletrônica ao anel porfirínico. Apesar do forte acoplamento eletrônico entre os grupos perféricos e o central, as propriedades eletrônicas dos complexos de rutênio foram preservadas, exibindo potenciais redox muito próximos dos complexos livres e comportamento espectroeletroquímico típicos de complexos metálicos N-heterocíclicos. Esses aspectos levam a novas perspectivas relacionadas à estrutura dos compostos, pois são potencialmente interessantes para o estudo referente à formação de oxigênio singlete e para PDT. Outro direcionamento desta tese, foi o de explorar a geração de novas interfaces baseadas na formação de pares iônicos constituídos pelas espécies H2TPyPzTRu/CuTSPc em comparação com o filme da espécie catiônica H2TPyPzTRu. Através de medidas de espectroscopia de impedância eletroquímica, foram constatados mecanismos distintos de condução nos filmes formados, que pode ser ou um mecanismo misto envolvendo os complexos periféricos e o anel central da porfirazina, ou um mecanismo de condução eletrônica envolvendo somente o sistema de empilhamento π do anel central da porfirazina. / In this work, we describe the synthesis, characterization and properties of derived tetra(3,4-pyridil)porphyrazine complex containing four [Ru(bipy)2Cl]1+ groups. The electronic conjugation between the pyridinium moiety and the porphyrazine ring promote an efficient communication between the peripherical groups and central ring, which is reflected in the emission spectrum and related excitation profile. The observed behavior reveals an efficient antenna effect in the H2TPyPzTRu system. ln spite of the strong electronic coupling between the central and peripherical groups, the electronic properties of ruthenium complex were preserved, exhibiting redox potencials very close to those of free complexes. These aspects provided new perspectives of exploiting the compound strutures, particularly the oxygen singlet formation and PDT application. Another aspect focused in this investigation was the generation of new interfaces based on ion-pair formation of H2TPyPzTRu/CuTSPc, in comparison with its cationic species H2TPyPzTRu alone. By means of electrochemical impedance spectrocopy, it was shown that the conduction mecanisms in these films involve either the peripherical complex and the central porphyrazine ring.

Die vorliegende Arbeit hat neben der Untersuchung der Synthese über den Controlled SBU-Approach von HKUST-1, ein poröses Kupfertrimesat, die Abscheidung dieses Metal-Organic Frameworks in dünnen Quarzglaskapillaren mit einer Länge von 10 bis 30 m und Innendurchmessern zwischen 0,53 und 0,25 mm zum Thema. Diese Säulen werden zur gaschromatographischen Trennung wie auch zur Bestimmung physikochemischer Kenngrößen, die den Adsorptionsvorgang verschiedener Analyten auf der HKUST-1 Oberfläche beschreiben, verwendet. Zu den untersuchten Stoffen gehören neben unpolaren n-Alkanen, unterschiedlich substituierte Phenylaromaten und starke Lewisbasen, wie Alkoxyalkane. Bei diesen kann der Einfluss der Gestalt und Länge der an den Sauerstoffatomen befindlichen Alkylgruppen auf die Adsorption an HKUST-1 in Form von spezifischen und unspezifischen Wechselwirkungsenthalpien, bestimmt aus gaschromatographischen Messungen, und infrarotspektroskopischen Auswertungen untersucht werden. Abschließend wird eine quantitative Aussage über das Verhältnis von Acidität und Basizität der HKUST-1 Oberfläche getroffen.

Les sels d’imidazolium ont un rôle important dans certaines protéines et acides nucléiques et ont été utilisés à de nombreuses reprises dans des assemblages supramoléculaires en raison de leurs propriétés uniques. Les sels de diimidazolium dérivés sont toutefois moins connus. Ils ont pour l’instant uniquement été utilisés comme des précurseurs de carbènes N-hétérocycliques. Ils sont donc à la base de plusieurs catalyseurs utilisés pour des réactions de couplage croisés mais leurs propriétés sont toutefois méconnues dans le cadre de la chimie supramoléculaire. Cette classe de composés a nottament attiré notre attention en raison de la facilité de modification de leurs propriétés physico-chimiques par modification de leur structure chimique. L’objectif général des travaux présentés dans cette thèse est l’étude des propriétés supramoléculaires des sels de diimidazolium disubstitués en solution (aqueuse ou organique), ainsi qu’en phase solide ou cristal-liquide. L’influence de l’espaceur entre les deux noyaux imidazolium ainsi que l’influence des substituants latéraux et des contre-ions a été étudiée. Dans un premier temps, les propriétés de complexation des sels de diimidazolium à des macrocycles sont étudiées. Les sels bromure sont étudiés en solution aqueuse avec plusieurs cyclodextrines et le cucurbit[7]uril, et les sels hexafluorophosphate sont étudiés en solution organique pour leur complexation avec l’éther couronne DB24C8 et un calix[4]arène. Cette nouvelle classe de composés a montré de très bonnes propriétés de complexation à ces différents macrocycles en solution et a également permis de contrôler différents assemblages supramoléculaires à l’interface air-eau. Dans un deuxième temps, l’étude des sels de phénylènediimidazolium a permis de modifier les propriétés de complexation en solution pour obtenir la formation de complexes multiples avec le cucurbit[7]util en solution aqueuse. Cette même famille de composés a également permis la formation de cristaux liquides ioniques lorsque les substituants sont des chaînes alkyles plus longues. La résolution de plusieurs structures cristallines de différents sels de diimidazolium a finalement permis de comprendre la nature des interactions intermoléculaires à l’état cristallin. La recherche présentée dans cette thèse a donc permis une étude détaillée des propriétés supramoléculaires des sels de diimidazolium dans tous les états de la matière qui leur sont accessibles. / Imidazolium salts play an important role in different proteins and nucleic acids and have been used many times in supramolecular assemblies due to their unique properties. Diimidazolium salts derived from imidazolium salts are less known. To date, they have only been used as precursors for N-heterocyclic carbenes, which are used to catalyze various cross-coupling reactions. Their properties are not well known in supramolecular chemistry. This class of compounds attracted our attention because of the ease of tuning their properties by modifying their chemical structure. The main goal of the research presented in this thesis was to study the supramolecular properties of disubstituted diimidazolium salts in solution (aqueous or organic solution), in the solid state and in the liquid-crystalline state. The role of the spacer between the two imidazolium moieties, of the sidechains and of the counterions was studied. Firstly, the complexation between diimidazolium salts and various macrocycles was studied. Bromide salts were studied in aqueous solution with cyclodextrins and cucurbit[7]uril, while hexafluorophosphate salts were studied in organic solution with a DB24C8 crown ether and a calix[4]arene. This novel class of compounds showed very promising complexation properties with these macrocycles in solution and also allowed us to control the formation of various supramolecular assemblies at the air-water interface. Secondly, phenylenediimidazolium salts were studied and allowed the modification of the complexation properties in aqueous solution. Multiple complexes can be formed simultaneously with cucurbit[7]uril in aqueous solution. The same class of compounds also has the ability to yield ionic liquid crystals when the alkyl sidechains are long. The resolution of the crystalline structures of some synthesized diimidazolium salts allowed us to understand the nature of the intermolecular interactions in the solid state. The research presented in this thesis is a complete study of the supramolecular properties of diimidazolium salts in every accessible state of matter.

La chimie supramoléculaire est un domaine qui suscite depuis quelques années un intérêt grandissant. Le domaine s’appuie sur les interactions intermoléculaires de façon à contrôler l’organisation moléculaire et ainsi moduler les propriétés des matériaux. La sélection et le positionnement adéquat de groupes fonctionnels, utilisés en combinaison avec un squelette moléculaire particulier, permet d’anticiper la façon dont une molécule interagira avec les molécules avoisinantes. Cette stratégie de construction, nommé tectonique moléculaire, fait appel à la conception de molécules appelées tectons (du mot grec signifiant bâtisseur) pouvant s’orienter de façon prévisible par le biais d’interactions faibles et ainsi générer des architectures supramoléculaires inédites. Les tectons utilisent les forces intermoléculaires mises à leur disposition pour s’orienter de façon prédéterminée et ainsi contrecarrer la tendance à s’empiler de la manière la plus compacte possible. Pour ce faire, les tectons sont munies de diverses groupes fonctionnels, aussi appelés groupes de reconnaissance, qui agiront comme guide lors de l’assemblage moléculaire. Le choix du squelette moléculaire du tecton revêt une importance capitale puisqu’il doit permettre une orientation optimale des groupes de reconnaissance. La stratégie de la tectonique moléculaire, utilisée conjointement avec la cristallisation, ouvre la porte à un domaine de la chimie supramoléculaire appelé le génie cristallin. Le génie cristallin permet l’obtention de réseaux cristallins poreux soutenus par des interactions faibles, pouvant accueillir des molécules invitées. Bien que toutes les interactions faibles peuvent être mises à contribution, le pont hydrogène est l’interaction prédominante en ce qui a trait aux réseaux cristallins supramoléculaires. La force, la directionnalité ainsi que la versatilité font du pont hydrogène l’interaction qui, à ce jour, a eu le plus grand impact dans le domaine du génie cristallin. Un des groupements de reconnaissance particulièrement intéressants en génie cristallin, faisant appel aux ponts hydrogène et offrant plusieurs motifs d’interaction, est l’unité 2,4-diamino-1,3,5-triazinyle. L’utilisation de ce groupement de reconnaissance conjointement avec un cœur moléculaire en forme de croix d’Onsager, qui défavorise l’empilement compact, permet l’obtention de valeurs de porosités élevées, comme c’est le cas pour le 2,2’,7,7’-tétrakis(2,4-diamino-1,3,5-triazin-6-yl)-9,9’-spirobi[9H-fluorène]. Nous présentons ici une extension du travail effectué sur les cœurs spirobifluorényles en décrivant la synthèse et l’analyse structurale de molécules avec une unité dispirofluorène-indénofluorényle comme cœur moléculaire. Ce cœur moléculaire exhibe les mêmes caractéristiques structurales que le spirobifluorène, soit une topologie rigide en forme de croix d’Onsager défavorisant l’empilement compact. Nous avons combiné les cœurs dispirofluorène-indénofluorényles avec différents groupements de reconnaissance de façon à étudier l’influence de l’élongation du cœur moléculaire sur le réseau cristallin, en particulier sur le volume accessible aux molécules invitées. / Supramolecular chemistry is a field of rapidly increasing interest in recent years. The field uses weak intermolecular interactions to control molecular organisation and therefore modulate the properties of materials. Adequate selection and positioning of functional groups, combined with a carefully selected molecular core to which the groups are attached, allows for the creation of molecules with a high degree of predictability in the way they will interact with their neighbours. This approach to the design and construction of materials, called molecular tectonics, is based on subunits called tectons (derived from the Greek word for builder), which use weak interactions to organise themselves in a predictable manner and generate novel supramolecular architectures. In favorable cases, the interactions can counter the general tendency shown by molecules to pack together in a compact manner. Instead, specific functional groups direct molecular recognition and help guide the process of auto-assembly. At the same time, the molecular core of the tecton is also of capital importance as it must allow an optimal orientation of the recognition groups. The molecular tectonics approach, used jointly with crystallisation, opens the door to new opportunities in crystal engineering. For example, crystal engineering now allows the logical creation of porous crystalline networks that can accept guest molecules. Although any type of weak interaction can hold such networks together, the hydrogen bond is favored for constructing porous supramolecular networks. The strength, directionality and versatility of the hydrogen bond accounts for its special importance in the domain of crystal engineering. A recognition group of particular interest in crystal engineering is the 2,4-diamino-1,3,5-triazinyl unit. This unit forms hydrogen bonds according to various standard motifs. The use of this recognition group, joined to molecular cores specifically designed to inhibit close packing, such as Onsager crosses, allows for the construction of supramolecular networks with high porosity, as shown by the behaviour of 2,2’,7,7’-tetrakis(2,4-diamino-1,3,5-triazin-6-yl)-9,9’-spirobi[9H-fluorene]. We present here an extension of previous studies of spirobifluorenyl cores by describing the synthesis and structural analysis of molecules with related dispirofluorene-indenofluorenyl cores. This new core offers the same characteristics as the spirobifluorenyl core, namely rigid topology and an Onsager cross molecular shape which are known to inhibit close packing. We have combined this core with a variety of recognition groups to verify the influence of the molecular core on the crystalline networks generated, particularly on the volume accessible to guest molecules.

Self-assembly processes were used to construct supramolecular architectures based on metal-ligand interactions. The structures formed strongly depend on the used metal ion, the ligand type, the chosen counter ion and solvent as well as on the experimental conditions. The focus of the studies was the design of multifunctional N-donor ligands and the characterization of their complexing and structural properties. This work was divided into three distinct main parts: The bis(2-pyridylimine), the bis(2-hydroxyaryl) imine and the tripodal imine / amine ligand approach. In the first part a series of bis(2-pyridylimine) derivatives having different linking elements were employed as building blocks for novel supramolecular architectures. Reaction of individual d-block metal salts with these ligands has led to the isolation of coordination polymers, a metallamacrocycle, double-stranded helicates, triple-stranded helicates as well as of circular meso-helicates. The nature of the spacer in the Schiff base ligands, the noncovalent weak interactions, such as hydrogen bond, face-to-face π-π and edge-to-face CH-π interactions, are all important factors influencing the architecture of the final products. Topological control of the assembly process of the hexanuclear meso-helicates is clearly associated with the bidentate coordination of the sulfate anion which directs the formation of a double- rather than a triple-stranded helicate around the octahedrally coordinated Cu(II). Surprisingly, the variation of the linker function in the ligands, which significantly changes the linking angle of the pyridylimine strands, has only a little influence of the resulting structure. Also the use of a mixture of ligands does not influence the meso-helicate topology; the result is the symmetrically mixed meso-helicate. The new iron(II) triple helicate [Fe2(L5)3](PF6)4 14 {L5 = bis[4-(2-pyridylmethyleneimino)phenyl]-1,1-cyclohexane} in its chloride form binds strongly to DNA as confirmed by induced circular dichroism signals in both the metal-to-ligand charge transfer (MLCT) and in-ligand bands of the helicate. The induced CD spectrum gives some evidence that [Fe2(L5)3]4+ interacts with the DNA in a single binding mode, which is consistent with major groove binding. The cytotoxicity of the new iron(II) triple helicate 14 was evaluated on human lung cancer A549 cells and compared with that of cisplatin and that of the previously reported iron(II) triple helicate [Fe2(L1)3]4+{L1 = bis[4-(2-pyridylmethyleneimino)phenyl]methane}. The first results show some distinguishing features for 14 obviously caused by the existing structural differences of the complexes. In the second part of the thesis, novel uranyl complexes of the bis(2-hydroxyaryl) imine ligands have been synthesized and characterized. 1D coordination polymers and mononuclear structures were formed. In all complexes a distorted hexagonal bipyramidal coordination geometry around the uranyl centre is observed. The imine nitrogen atoms of the ligands do not bind to the metal centre but interact strongly with the hydroxy group via H-bonding. DFT calculations made with L8 ( α,α’-Bis(salicylimino)-m-xylene) are in good agreement with the X-ray crystal structure data. Liquid-liquid extraction studies involving selected ligands and Eu(III) or U(VI) indicate remarkably high selectivity for U(VI) over Eu(III) at weak acidic pH conditions. We believe that the study made opens up new possibilities for uranyl ion extraction which could be interesting in view of the treatment of nuclear waste. In the third part of the thesis, a series of multifunctional tripodal ligands with different N-donor centres were used for U(VI) and lanthanide, Nd(III), Eu(III) and Yb(III), binding and extraction. Reaction of these metal ions with selected tripodal ligands afforded complexes which were characterized by ESI mass spectroscopy. The complex composition was found to be 1:1 in all cases. The extraction behaviour of the tripodal ligands towards Eu(III) and U(VI) was studied both in the absence and presence of octanoic acid as co-ligand using the extraction system Eu(NO3)3 or UO2(NO3)2–buffer–H2O/ ligand–CHCl3. These separation systems show a remarkably high selectivity for U(VI) over Eu(III). It is interesting to note that the addition of the octanoic acid to the extraction system leads to high synergistic effects. A series of Eu(III) extraction experiments were done to clarify the composition of the extracted complexes. The results clearly point to the formation of various species with changing composition.

Dans cette thèse, nous avons étudié le mécanisme fondamental du processus d'auto-assemblage thermoréversible des trisamides triarylamines chiraux. Nous avons ensuite étudié les utilisations possibles de dérivés de triarylamine dans différents domaines de recherche liés à la science des matériaux. Premièrement, en utilisant une approche biocatalytique, nous avons réussi à contrôler l'auto-assemblage d’amphiphiles à base de TAA-peptide conjugués dans l'eau. Deuxièmement, de nouveaux dérivés de triarylamine ont été incorporés avec succès en tant que couches conductrices de trous dans des cellules solaires de type pérovskite. Troisièmement, nous avons démontré la possibilité de déclencher électrochimiquement l'auto-assemblage de triarylamines pour la construction anisotrope contrôlée de nanofils conducteurs. Enfin, nous avons développé une technique qui permet l'alignement hautement ordonné de nanoparticules d'or sur une couche de nanofils de triarylamines à l'interface liquide-liquide. / In this thesis, we have explored the fundamental mechanism of the thermally initiated self-assembly process of chiral triarylamine trisamides. The results demonstrate a cooperative nucleation and growth mechanism with well-defined thermal hysteresis and memory effect. We have then studied the possible implementations of triarylamine derivatives in various fields of material sciences. First, by taking advantage of a biocatalytic approach, we managed to control the self-assembly of TAA-peptide amphiphiles in water. Second, new triarylamine derivatives were successfully inserted as hole transporting layers in perovskite solar cells. Third, the self-assembly of triarylamines was triggered electrochemically, leading to an anisotropic construction of conducting nanowires. Finally, we developed a technique that allows for the highly ordered alignment of gold nanoparticles over a layer of triarylamine nanowires at the liquid-liquid interface by simple centrifugation of a biphasic mixture.

No description available.

No description available.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Triazenes are a class of compounds characterized by the presence of a diazoamino functional group (N=N N) showing remarkable ability to support the stereochemical requisites of a wide variety of metal transition complexes. They act as versatile ligands in coordination chemistry when deprotonated and have relevant biological and synthetic porperties. This work presents the synthesis and investigation of molecular and crystal structure of a new series of monotriazenes [3-(4-phenyldiazenyl)-1-(2-fluorophenyl)triazene (2b); 1-(2-chlorophenyl)-3-(4-phenyldiazenyl)triazeno (2c), 1-(2-bromophenyl)-3-(4-phenyldiazenyl)triazene (2d); 3-(4-phenyldiazenyl)-1-(2-iodophenyl) triazene (2e); 1,3-bis-(3-methoxy-4-methylbenzoate)triazene (2g)] and substituted 1,4-bis (phenyltriazenyl)butanes, C6H5N(H)=N-N(CH2)4-N=NN(H)C6H5, [1,4-bis(4-ethyl-benzoato triazenyl) butane (5a), 1,4-bis(2-fluorophenyltriazenyl)butane (5b), 1,4-bis(2-clorophenyltriazenyl)butane (5c), 1,4-bis(2-bromophenyltriazenyl)butane (5d), 1,4-bis(2-iodophenyltriazenyl)butane (5e), 1,4-bis(4-amidophenyltriazenyll)butane (5f)]. The insertion of groups on phenyl rings attached to the triazene chains makes the environment significantly more interesting coordination providing the supramolecular array through noncovalent intermolecular interactions and self-organizatinal units of primary molecule. The metal ions used for complexation are salts of Ni2+, Cu2+ and Pd2+ and they were chosen due to the attracting biological relevance, magnetic properties, catalytic yielding. Nine metal complexes unpublished were synthesized [trans-[PdII(C6H5NNC6H4NNNC6H4Cl)2(C5H5N)2] (3c) [(PdII (R1R2C6H3NNNC6H3R1R2)(PPh3)2Cl) DMSO] [R1 = 4-C(O)OCH3, R2 = 3-OCH3] (3g) [CuII (RC6H5NNN(CH2)4NNNC6H5R)]2 [R = C2H5C(O)O (6a), R = F (6b), R = NH2C(O) (6f)], [NiII (RC6H5NNN(CH2)4NNNC6H5R)]2 [R = F (7b) R = Cl (7c) R = Br (7d) R = NH2C(O) (7f)]. The synthesis and characterization of these compounds is justified by the exploration of the reactivity, the coordinative behavior and by the understanding of the interactions between different ligands and metal centers. The structural analysis of the synthesized compounds by X-ray diffraction on single crystal in the solid state were performed for characterization of interactions in the crystal. Thus, a thorough understanding of the relationship between the crystal structure and supramolecular organization is analyzed. Besides the structural analysis of compounds, elemental analysis CHN, infrared, nuclear magnetic resonance and ultraviolet-visible spectroscopies and mass spectrometry were also carried out for characterization. The physical chemical properties were investigated through thermogravimetric analysis and magnetic susceptibility. / Triazenos são importantes membros da família de compostos nitrogenados de cadeia aberta, caracterizados por conter o grupo funcional [N═N─N] e apresentam diferentes propriedades de coordenação a metais de transição. São compostos fracamente ácidos e quando desprotonados atuam como ótimos ligantes na química de coordenação apresentando grande importância sintética e biológica. Nessa tese, foi inicialmente desenvolvida a síntese de uma série inédita de compostos triazenos monocatenados [3-(4-fenildiazenil)-1-(2-fluorofenil)triazeno (2b); 1-(2-clorofenil)-3-(4-fenildiazenil)triazeno (2c); 1-(2-bromofenil)-3-(4-fenildiazenil)triazeno (2d); 3-(4-fenildiazenil)-1-(2-iodofenil)triazeno (2e); 1,3-bis(3-metoxi-4-metilbenzoato)triazeno (2g)] e de compostos triazenos biscatenados derivados do 1,4-bis(feniltriazenido)butano, C6H5N(H)N=N-(CH2)4-N=N-N(H)C6H5, [1,4-bis(etil-4-benzoatotriazenil) butano (5a); 1,4-bis(2-fluorofeniltriazenido)butano (5b); 1,4-bis(2-clorofeniltriazenido)butano (5c); 1,4-bis(2-bromofeniltriazenido)butano (5d); 1,4-bis(2-iodofeniltriazenido)butano (5e); 1,4-bis(4-amidofeniltriazenido)butano (5f)]. A inserção de grupamentos substituintes nos anéis fenila na cadeia triazenídica tornam o ambiente de coordenação significativamente mais interessante, propiciando o aumento da ocorrência de interações intermoleculares não covalentes e impondo a auto-organização de unidades moleculares primárias no estado sólido. Os metais escolhidos para complexação foram sais de Ni2+, Cu2+ e Pd2+ em virtude de atraírem atenção como objeto de estudos relacionados com medicina, propriedades magnéticas e catálise obtendo-se como resultados deste trabalho nove complexos metálicos inéditos [trans-[PdII(C6H5NNC6H4NNNC6H4Cl)2(C5H5N)2] (3c); [(PdII(R1R2C6H3NNNC6H3R1R2)(PPh3)2Cl)·DMSO] [R1 = 4-C(O)OCH3, R2 = 3-OCH3] (3g); [CuII(RC6H5NNN(CH2)4NNNC6H5R)]2 [R = C2H5C(O)O (6a); R = F (6b); R = NH2C(O) (6f)] ; [NiII(RC6H5NNN(CH2)4NNNC6H5R)]2 [R = F (7b); R = Cl (7c); R = Br (7d); R = NH2C(O) (7f)]. A síntese, e a caracterização desses novos compostos estão relacionadas à exploração da reatividade, ao comportamento coordenativo e a compreensão das interações entre os diferentes centros metálicos e os ligantes. Efetuou-se um estudo estrutural no estado sólido para a caracterização das interações presentes nas estruturas cristalinas dos compostos sintetizados e a ferramenta utilizada foi à difração de raios X em monocristal. Dessa forma aprofundou-se a compreensão da relação entre a estrutura cristalina e sua organização supramolecular. Além do método de difração de raios X de monocristal os compostos foram caracterizados por espectroscopia de infravermelho, espectroscopia de ressonância magnética nuclear, 1H e 13C, espectroscopia ultravioleta e visível, espectrometria de massas e análise elementar CHN. As propriedades físico-químicas foram investigadas através de análise termogravimétrica e susceptibilidade magnética.

The alluring order in which complex biological networks exist in nature stimulated the interest of chemists to replicate such systems synthetically. With such examples as the deoxyribonucleic acid (DNA) double helix and the phospholipid bilayers, the influence of forces within these networks are solely credited for their excellent stability. The synthetically ordered chemical networks are also held together by interactions within them with little or no external force as seen in the natural systems. This spontaneous and reversible association of molecules or ions to form larger, more complex entities according to the intrinsic information contained in the molecules themselves is known as self-assembly. The self-assembly process is pre-eminent to the formation of ordered structures emerging spontaneously from the precursors in which, the overall structure of the final assemblies is controlled by the symmetry of each of the building blocks. The highly ordered and thermodynamically stable scaffolds are formed via non-covalent interactions including hydrophobic interaction, π-stacking, dipole-dipole interaction, ion-dipole interaction, hydrogen bonding, Van der Waals forces, solvophobic interaction and reversible metal-ligand coordination. These non-covalent interactions are termed as supramolecular interactions. Among several of these self-assembly protocols, the directional metal-ligand coordination strategy has evolved to be a well-established process for the preparation of supramolecular ensembles with pre-defined shapes, cavities and functionalities in a “one-pot” synthesis. Coordination-driven self-assembly strategy is governed by the combination of electron-deficient metal centres and electron-rich organic ligands. The outcome of the final supramolecular architecture is determined by the choice of the pre-designed metal acceptor building blocks as well as the flexibility and steric demands of the ancillary organic ligands. Accurate stoichiometry of each of the building blocks is also a very important factor in coordination-driven self-assembly; although serendipity sometimes happen which is quite unexpected. A large number of these self-assembled supramolecular networks have found useful applications in optoelectronics, material chemistry, adsorption, drug delivery, catalysis, host-guest chemistry, photo- and electro-chemical sensing as well as prospective chemotherapeutics. Transition metals are widely desired as electron-deficient building blocks in supramolecular chemistry. They readily accept lone pair of electrons from electron-rich building blocks. The functional properties of these metals have also been considered during the pre-design of these electron acceptors such that the functional property of each metal can be induced in the final architecture. Pd(II) and Pt(II) metals are highly desirable electron acceptors in supramolecular self-assembly because of their rigid square-planar nature. Nonetheless, Ru(II) and Fe(II) have also been explored as electron acceptors based on their octahedral geometry. Electron-rich building blocks have lone pairs of electrons on their donor sites (nitrogen, oxygen or sulphur) which effortlessly donate electrons to electron-deficient building blocks. The pyridyl appended ligands have been mostly used as the electron-rich building blocks in the construction of supramolecular architectures because of their predictable coordination modes and the symmetrical nature. However, imidazole appended ligands holds a distinctive spot in supramolecular chemistry because of its rotational flexibility and unpredictable binding modes which may lead to uncommon architectures not obtainable with pyridyl appended ligands. Thus, imidazole-based supramolecular architectures are less explored because the outcome of the final architecture cannot be pre-determined during the design. Ruthenium p-cymene complexes have spurred much interest in the last two decades because they possess extremely stable octahedral geometry and has been extensively used in the construction of 2D and 3D supramolecular architectures. The recent search for viable alternatives to platinum drugs in cancer chemotherapy discovered ruthenium as an excellent alternative to platinum because of its low toxicity when compared to platinum. The robustness of the arene head on interaction with biomolecules and the accumulation of large molecular weight compounds specifically in cancer cells rather than in healthy cells also improved the activity of ruthenium supramolecular architectures in cancer therapy. This recent outcome has propelled significant research channelled towards synthesizing better ruthenium-based chemotherapeutics. Additionally, the presence of two different metals in a single self-assembled architecture may also impart an increased activity when compared to the individual activity of each metal. Thus, the heterometallic supramolecular architectures can open a new kind of chemotherapeutics which may give a distinct mechanistic pathway different from those reported in literature. Chapter 1 of this thesis describes the coordination-driven self-assembly strategy with specific emphasis on ruthenium p-cymene self-assembled architectures and their applications. A brief introduction on cancer and cancer therapy is discussed. The use of mononuclear and dinuclear metal-based chemotherapeutics is included while the use of heterometallic complexes as anticancer agents was also highlighted. Chapter 2 showcases the self-assembly of a series of 2D and 3D ruthenium(II) p-cymene architectures constructed from bidentate and tridentate rigid imidazole-based ligands and dinuclear ruthenium(II) building units. The influence of the rotational flexibility of the imidazole ligands on the final architecture was probed. In spite of the likelihood of the formation of different conformational isomeric architectures (syn and anti) and/or polymeric products due to free rotation on the donor sites of the imidazole ligands, the exclusive formation of a single conformational isomer (anti) as the only product turned out to be a noteworthy observation. This indicates that the coordination mode and flexibility of imidazole ligand can control and determine the geometry, topology and conformations of the final molecular architectures. Scheme 1: Self-assembly of 2D macrocycles [2 - 7](OTf)4 employing dinuclear ruthenium(II) building units [1a - 1c](OTf)2 and bidentate rigid imidazole ligands L1 - L2 in methanol at room temperature. Furthermore, the unexpected formation of a tetranuclear cationic macrocycle [8](OTf)4 was reported in the 2 + 3 self-assembly reaction of triazine-based tridentate imidazole ligand L3 and dinuclear ruthenium(II) building unit [1a](OTf)4 over the expected hexanuclear prismatic cage [8a](OTf)6 which is quite surprising. Scheme 2: Schematic representation of the formation of an unexpected tetranuclear macrocycle [8](OTf)4 over the expected hexanuclear prismatic cage [8a](OTf)6. Chapter 3 reports the synthesis of eight octanuclear cages via the coordination-driven self-assembly of two tetradentate pyridyl-based organic ligands and four dinuclear p-cymene Ru(II) acceptor clips. These octanuclear cages were explored in vitro as potential anticancer agents against human lung adenocarcinoma A549 and human cervical cancer HeLa cell lines. Four of the cages with polyaromatic spacers in their Ru(II) acceptor clip unit showed very low micromolar IC50 values and also possess higher anticancer activity than cisplatin against the tested cancer cell lines. The four dinuclear p-cymene Ru(II) acceptor clips A3 in OC-3 and OC-7 revealed some kind of synergy which is evident in their IC50 values against the tested cancer cell lines. In addition, OC-3 and OC-7 trigger both early and late apoptotic phases while OC-4 and OC-8 trigger majorly late apoptotic phase in the cancer cell lines tested. The mechanistic pathway by which cell death is progressing is through the generation of reactive oxygen species (ROS) which is of significant amount in OC-4 and OC-8. Scheme 3: Self-assembly of the discrete octanuclear cages (OC-1 - OC-8) in methanol at room temperature and the schematic illustration of the apoptosis mechanistic pathway. Chapter 4 describes the use of “metalloligands” as electron-rich building blocks and the subsequent use of the metalloligand for “one-pot” self-assembly reactions in the presence of electron-deficient metal acceptor building blocks. The pyridyl donors are the most preferred in metalloligands because of their predictable directionality in self-assembly. The introduction of a second metal into the ligand component of the self-assembled architecture is to bestow additional functionality as well as to construct elegantly designed discrete heterobimetallic supramolecular architectures. Four discrete Ru(II)-Pt(II) hexanuclear trigonal prismatic cages were synthesized employing a tritopic platinum(II) metalloligand and four p-cymene ruthenium(II) clips via coordination-driven self-assembly. The formation of these cages were confirmed by well-known spectroscopic techniques and their structural features was elucidated by geometry optimization. In vitro anticancer studies of these heterometallic cages failed because of solubility challenges in the culture media presumably due to their high molecular weights and many alkyl groups. Scheme 4: Energy minimized structures of the heterometallic trigonal prismatic cages 3a (left) and 3b (right). Hydrogen atoms have been removed for the sake of clarity [Ru: green, Pt: pink, O: red, N: blue, P: orange, C: grey]. Chapter 5 discusses the synthesis of two bidentate platinum(II) metalloligands as well as the self-assembly of six new heterometallic rectangles obtained from four Ru2(OOꓵOO)2(p-cymene)2Cl2 pillars and two bidentate pyridyl-based platinum(II) metalloligands. The Ru4Pt2 and Ru4Pt4 rectangles were structurally characterized and supported by geometry optimisation. Additionally, two Ru4Pt2 and two Ru4Pt4 rectangles were examined for their anticancer properties in eight human cancer cell lines with the aim of checking if the platinum metal centres in the metalloligands can enhance the anticancer activity of the rectangles. The results showed that these heterometallic rectangles are cytotoxic against the cancer cell lines tested but the incorporation of platinum(II) metal(s) into the metalloligand did not further enhance the cytotoxicity in the rectangles tested as hypothesized. The mechanism of cell death is via the generation of reactive oxygen species (ROS) and two Ru4Pt4 rectangles activates both early and late apoptosis. Cell cycle analysis showed that one of the Ru4Pt4 rectangles is a moderate inhibitor of cell cycle progression at the sub G1 phase similar to cisplatin while nuclear condensation and cell blebbing in the cells was also observed in the presence of the two Ru4Pt4 rectangles tested. The overall activity of the heterometallarectangles against the cancer cell lines tested was increased when they exist as a single entity thus reiterating the importance of heterobimetallic supramolecular architectures in cancer therapy. Scheme 5: Schematic diagram of the discrete Ru4Pt4 heterometallic rectangles and illustration of the cell death pathway. The results of the investigation reported in this thesis contribute to the rapidly developing field of organometallic ruthenium(II) self-assembled anticancer chemotherapeutics with specific evidences of the mechanistic pathway of cell death. This results can further guide the design and development of better chemotherapeutics for future use.