Este trabalho tem como objetivo a síntese e a determinação de propriedades micelares de líquidos iônicos tensoativos (LITs) catiônicos. Dentre as características importantes desses compostos destacamos: alta deslocalização da carga e caráter ácido no hidrogênio H2 do anel heterocíclico e a grande flexibilidade estrutural, estas são relevantes para as propriedades de soluções desses tensoativos, e, consequentemente, para suas aplicações. A influência da variação estrutural nas suas propriedades é importante para modular as propriedades micelares e, por consequência suas aplicações. A síntese de LITs foi realizada por aquecimento convencional e irradiação por micro-ondas, o último método foi o mais eficiente. Inicialmente, estudamos a influência do comprimento da cadeia carbônica (fator importante para a energia de formação de micelas), de cloretos de 1-alquil-3-metilimidazólio, tendo a cadeia n-alquílica 10 a 16 átomos de carbonos. Em seguida, comparamos as propriedades dos LITs acima mencionados com as de tensoativos convencionais, cloretos de 1-alquilpiridínio e cloretos 1-alcanoil-amidoetil benzildimetilamônio. Por fim, estudamos a influência do volume da cabeça-polar, utilizando cloretos de 1-alquil-3-hexadecilimidazólio, tendo a cadeia alquílica secundária 1 a 5 átomos de carbono. As propriedades micelares foram investigadas por tensão superficial, condutividade, calorimetria, espalhamento de luz e ressonância magnética nuclear. Os resultados mostraram que ligações de hidrogênio (devido ao H2 ácido do anel imidazólio) e as interações hidrofóbicas são relevantes para a formação de micelas e que o aumento do volume da cabeça-polar favorece a micelização e a formação de agregados pré-micelares / The objective of this work is the synthesis and determination of the micelar properties of cationic surface-active ionic liquids (SAILs). Among the important characteristics of these compounds are: high charge delocalization and acid character of hydrogen H2 of the heterocyclic ring and large structural flexibility, the latter is relevant to solution properties of these surfactants, hence to their applications. Synthesis of SAILs was carried out by conventional heating or by microwave irradiation, the later method was more efficient. Initially, we studied the influence of the chain length of the alkyl group (an important factor for the energy of micelle formation) of 1-alkyl-3-methylimidazolium chlorides, n-alkyl group having 10 to 16 carbon atoms. Then, we compared the properties of the above mentioned SAILs with conventional surfactants, 1-alkylpyridinium chlorides and 1-alkanoyl-amidoethyl benzyldimethylammonium chlorides. Finally, we studied the influence of the head-group volume, by studying 1-alkyl-3-hexadecylimidazolium chlorides, with secondary n-alkyl group having 1 to 5 carbon atoms. The micelar properties were investigated by surface tension, conductivity, calorimetry, light scattering and nuclear magnetic resonance. Our results have shown that hydrogen bonding (due to the acidic H2 of the imidazolium ring) and hydrophobic interactions are relevant to micelle formation; increasing the head-group volume favors micellization and the formation of pre-micellar aggregates

Gegenstand dieser Arbeit ist die Synthese und Charakterisierung von Bis-1,3-azol-Derivaten insbesondere im Hinblick auf ihre potentielle Einsatzfähigkeit als chemisches Sensormaterial. Nach bereits bekannten Methoden gelang es, zehn neue Bisoxazol-Derivate sowie zehn neue Dicarbonsäurediester herzustellen. Weiterhin wurden 13 neue Bisimidazol- und vier neue Lophin-Derivate synthetisiert. Die erhaltenen Röntgeneinkristallstrukturanalysen zeigen, dass vor allem lineare Bisimidazol- und Bisoxazol-Derivate gute Eigenschaften als Clathratbildner aufweisen. Die Bisoxazol-Derivate mit Pyridin als Spacerelement eignen sich vorwiegend zur Komplexierung von Nickel(II)-, Kupfer(II)- und Kobalt(II)-ionen. Aus den fluoreszenzspektroskopischen Untersuchungen geht hervor, dass verschiedene Analytdämpfe unterschiedliche Auswirkungen auf die Festkörperfluoreszenz ausüben. Somit erscheint der Einsatz von Derivaten dieser Verbindungsklasse in chemischen Fluoreszenzsensoren erfolgversprechend.

Une large série d’imidazo[4,5-b]porphyrines a été synthétisée par condensation acido catalysée du 2,3-dioxo-5,10,15,20-tétraarylchlorines avec des aldéhydes aromatiques. Les propriétés stériques et électroniques des substituants méso-aryle sur le macrocycle tétrapyrrolique ont une influence importante sur le rendement en produit qui peut varier de 18% à 90%. L'analyse par diffraction des rayons X de la structure cristalline du 5,10,15,20-tétramésityl-2-(4-pyridyl)-1H-imidazo[4,5-b]porphyrinate de zinc(II) a montré qu'à l'état solide ce complexe forme des polymères de coordination. Ensuite, différentes méthodes de greffage des imidazoporphyrines sur la surface de TiO2 et ZrO2 mésoporeux ont été étudiées pour évaluer l'intérêt de ces matériaux hybrides en catalyse. La photo-oxydation en milieu homogène des sulfures en sulfoxydes par l'oxygène de l'air en présence de 5,10,15,20-tétramésityl-2-(4-diéthoxyphosphorylphényl)-1H-imidazo[4,5-b]porphyrinate d'indium(III) a été mis en œuvre. Il a été ainsi montré que le complexe supporté par le TiO2 pouvait être recyclé plusieurs fois malgré un lessivage partiel (1%) du catalyseur en solution. Puis, le 5,10,15,20-tétramésityl-2-(4-diéthoxyphosphorylphényl)-1H-imidazo[4,5-b]porphyrinate de manganèse(III) supportée par TiO2 a été utilisé comme catalyseur pour l'oxydation de sulfures en sulfoxydes par l'oxygène moléculaire en présence d'isobutyraldéhyde. Une large série de sulfoxydes a été préparée avec des rendements élevés (> 89%). Le catalyseur a été recyclé 7 fois sans perte de son efficacité et de sa sélectivité. Dans les conditions mises en jeu le lessivage du catalyseur en solution n'a pas été observé. / A broad series of functionalized imidazo[4,5-b]porphyrins was synthesized by the acid-catalyzed condensation of 2,3-dioxo-5,10,15,20-tetraarylchlorins with aromatic aldehydes. Both steric and electronic features of meso-aryl substituents influence on the product yield ranging from 18% to 90%.Single-crystal X-ray diffraction analysis of the structure of zinc(II) 5,10,15,20-tetramesityl-2-(4-pyridyl)-1H-imidazo[4,5-b]porphyrinate showed that this compound forms 1D coordination chains in the solid state.The post-synthetic modifications of imidazo[4,5-b]porphyrins were investigated by performing the Suzuki-Miyaura coupling reaction, preparing water-soluble imidazoporphyrins and linear/angular bis(imidazo)porphyrins.Several methods of grafting of imidazoporphyrins on the surface of mesoporous TiO2 and ZrO2 were investigated to prepare hybrid materials for catalysis.Then, it was demonstrated that indium(III) 5,10,15,20-tetramesityl-2-(4-diethoxyphospho-rylphenyl)-1H-imidazo[4,5-b]porphyrinate catalyzes the photooxidation of sulfides to sulfoxides by oxygen from air. This complex grafted on TiO2 surface was efficient as a reusable catalyst in spite of partial (1%) leaching of imidazoporphyrin in solution. TiO2-supported manganese(III) 5,10,15,20-tetramesityl-2-(4-diethoxyphosphoryl-phenyl)-1H-imidazo[4,5-b]porphyrinate was employed for catalytic oxidation of a broad range of sulfides by pure oxygen in the presence of isobutyraldehyde. All sulfoxides were obtained in high yields (>89%). The catalyst was reused in 7 consecutive cycles without loss of its efficiency and selectivity. Leaching of the catalyst was not observed under studied conditions.

The naturally occurring dipeptide carnosine (-alanyl-L-histidine) specifically attenuates tumor growth. Here, we ask whether other small imidazole-containing compounds also affect the viability of tumor cells without affecting non-malignant cells and whether the formation of histamine is involved. Patient-derived fibroblasts and glioblastoma cells were treated with carnosine, L-alanyl-L-histidine (LA-LH), -alanyl-L-alanine, L-histidine, histamine, imidazole, -alanine, and L-alanine. Cell viability was assessed by cell-based assays and microscopy. The intracellular release of L-histidine and formation of histamine was investigated by high-performance liquid chromatography coupled to mass spectrometry. Carnosine and LA-LH inhibited tumor cell growth with minor effects on fibroblasts, and L-histidine, histamine, and imidazole affected viability in both cell types. Compounds without the imidazole moiety did not diminish viability. In the presence of LA-LH but not in the presence of carnosine, a significant rise in intracellular amounts of histidine was detected in all cells. The formation of histamine was not detectable in the presence of carnosine, LA-LH, or histidine. In conclusion, the imidazole moiety of carnosine contributes to its anti-neoplastic effect, which is also seen in the presence of histidine and LA-LH. Despite the fact that histamine has a strong effect on cell viability, the formation of histamine is not responsible for the effects on the cell viability of carnosine, LA-LH, and histidine.

Deuteration is the replacement of a hydrogen atom by deuterium atom in a molecule. The replacement begins at the most acidic hydrogen in the molecule. In ATP, the deshielded hydrogen is C8-H which is the first replaced during deuteration. During ATP deuteration some of the ATP is hydrolysed to ADP concurrently. Using kinetic analysis, it was confirmed that the ATP hydrolysis that occurs is 1st order in ATP concentration, while the hydrogen replacement is 2nd order. The ATP and its C8 deuterated analogue were tested against three enzymes shikimate kinase (SK), acetate kinase (AK) and glutamine synthetase (GS) to determine if a kinetic isotope effect (KIE) exists in these systems. With AK and GS, the KIED increased as the KIEH decreased, while with SK the KIED decreased as the KIEH increased as the concentration of the ATP or deuterated analogue increased. Deuteration of imidazole and purine compounds reduced the specific activity of AK or SK at low concentrations in an enzyme-catalysed reaction. From a library of imidazole-containing compounds that inhibited SK, three compounds were selected and their IC50 values were determined on the SK-catalysed reaction. These compounds show a differential potency and efficiency between their protonated and deuterated analogues when compared in a 1:1 mixture. Synthesized purines incorporating three different substituents at N-9 were tested against AK or SK for their ability to lower the specific activity of the enzymes used / Physics / M. Sc. (Physics)

Ce travail est centré sur la synthèse de complexes du rhodium contenant un ligand azoté et leur mise en œuvre dans la réaction catalytique de carbonylation du méthanol en acide acétique. Dans une première partie, nous nous intéressons à la préparation de complexes neutres de formule générale [RhI2(CO)(L)] (L = amines, imidazoles et pyrazoles) et à quelques homologues chlorés. Ces complexes plans carrés manifestent une réactivité directement liée à l’encombrement stérique du ligand azoté L dans la réaction d’addition oxydante de l’iodomethane suivie de la cis-migration du groupement méthyle pour former l’espèce acétyle. Dans une deuxième partie, les complexes précédents ont été engagés dans des essais catalytiques de carbonylation du méthanol dans les conditions du procédé industriel. Comme il s’est avéré que les complexes neutres se transforment en espèce [RhI2(CO)2]- pour laquelle les contre-cations associés sont constitués du ligand azoté protoné ou methylé, nous avons effectué la préparation et la caractérisation des complexes [HNR3][RhI2(CO)2] ou [MeNR3][RhI2(CO)2]. Par IR, RMN et électrochimie, nous nous sommes intéressés aux phénomènes d’appariement d’ions et nous montrons qu’il s’agit dans le meilleur des cas d’interactions hydrogènes. Celles-ci influent la vitesse de la réaction oxydante de CH3I. Dans la dernière partie, nous avons complété une étude, précédemment initiée au laboratoire, sur le mécanisme, qui dans la dernière étape du cycle catalytique permet de passer de l’espèce acétyle [RhI3(COCH3)(CO)2]- à l’espèce active [RhI2(CO)2]- avec production de l’iodure d’acyle. A l’inverse du concept admis d’élimination réductrice de CH3COI suivie de son hydrolyse immédiate en CH3COOH et HI, nous montrons, avec l’appui de calculs théoriques (DFT) qu’en fait un ligand I- est substitué par un ligand acetate pour conduire à l’espèce [RhI2(OAc)(COCH3)(CO)2]-. L’élimination réductrice produit alors l’anhydride acétique qui est hydrolysé en CH3COOH régénérant [RhI2(CO)2]-. Un tel mécanisme opère en présence d’ions acetate dans les milieux faiblement hydratés visés par l’industriel. / This study focuses on the synthesis and reactivity of rhodium complexes bearing N- containing ligands or counter-cations for the [Rh]-catalyzed methanol carbonylation reaction to produce acetic acid under the industrial Celanese Acid Optimization (AO) process conditions. In a first part, full synthesis and characterization of neutral Rh(I) square planar cis- [RhX(CO)2(L)] (X = Cl or I) complexes have been described, for which L is an N-ligand belonging to the amine, imidazole or pyrazole family. For the [RhI(CO)2(L)] complexes, variable-temperature 13C{1H} NMR spectroscopy has put in evidence a fluxional behavior for the different sized L ligands involved. The rate of this fluxional process reveals to be related to both electronic and steric contributions brought by L to the Rh center. These parameters (mainly steric), supported by single-crystal X-ray analyses in the solid state, also influence significantly the kinetics of the methyl iodide oxidative addition reaction followed by rapid CO migratory insertion, the overall being the rate determining step of the [Rh]-catalyzed methanol carbonylation cycle. In absence of CO, this reaction gives rise to the corresponding neutral Rh(III) acetyl complex, which immediately dimerizes to afford [Rh(μ- I)I(COMe)(CO)(L)]2 complex, for which several X-ray crystal structures have been obtained and studied. In addition, the surprising C-H activation in the case of a tBu-pyrazole ligand giving rise to a cyclometalated Rh dimer is reported. In a second part, the reactivity of the latter neutral Rh(I) [RhI(CO)2(L)] complexes as potential precursors has been investigated by batch experiments for the methanol carbonylation reaction. Mechanistic understanding via VT-HP-NMR experiments enabled to detect mainly anionic Rh(I) [RL][RhI2(CO)2] (R = H or CH3 according to the working conditions) complexes formed by decoordination followed by quaternization of the L ligand. Despite this result, the pyrazole family ligands showed better stability under the harsh process conditions. Thus, it cannot be ruled out that equilibrium between neutral and anionic species co-exist in the reaction medium at high temperatures and that [RL]I salt dissociation occurs, restoring the L ligand into the Rh coordination sphere. At this stage we focused on the anionic Rh(I) complex and prepared a series of [XNR3][RhI2(CO)2] (X = H or CH3) species, which have been fully characterized. Infrared, NMR, conductivity experiments and DFT model calculations together put in evidence ion interactions according to the nature of the ammonium counter-cation. Protonated cations significantly impact on the kinetics of the methyl iodide oxidative addition presumably due to H-interactions with the Rh square plane. The final part deals with the mechanism of the reductive elimination reaction, the last step of the [Rh]-catalyzed methanol carbonylation cycle, which from complex [RhI3(COCH3)(CO)2]-, regenerates [RhI2(CO)2]-. In contrast to the classically admitted mechanism of reductive elimination of CH3COI followed by subsequent hydrolysis to form AcOH and HI, we demonstrate from experimental DFT calculation that substitution of an iodo ligand by an acetate ion occurs to give rise to the [RhI2(OAc)(COCH3)(CO)2]- species. Thus, reductive elimination regenerates [RhI2(CO)2]- and produces acetic anhydride, which after hydrolysis affords two molecules of acetic acid. Such a mechanism operates under process conditions at low water content with a significant amount of acetate ions.

A fusion protein composed of antibody fragments and β-lactamase was earlier created by Kojima et al. (2011), with antigen specificities against a bone disease marker and a pesticide. The enzyme was circularly permutated and fused to the variable heavy and light chain antibody fragments, thereby ensuring inactivity until binding of the target antigen triggered enzyme activation. Upon activation, the β-lactamase produced a colorimetric signal, which indicated antigen presence. In this work, a similar strategy was used to create two novel fusion proteins composed of circularly permuted β-lactamase and superfolder green fluorescent protein with anti-benzo[a]pyrene variable antibody fragments. The fusion proteins were designed and expressed in E. coli for the development of a single-step visual immunoassay. It was hypothesized that the cp reporter proteins would be activated once the binding of B[a]P to the variable antibody fragments occurred, and this interaction was expected to produce a detectable colorimetric or fluorescent signal. Although positive results were obtained in one instance, substantial supportive evidence in favour of the hypothesis could not be obtained. / SENTINEL Bioactive Paper Network, Natural Sciences and Engineering Research Council of Canada (NSERC), Canada Research Chairs Program.

Deuteration is the replacement of a hydrogen atom by deuterium atom in a molecule. The replacement begins at the most acidic hydrogen in the molecule. In ATP, the deshielded hydrogen is C8-H which is the first replaced during deuteration. During ATP deuteration some of the ATP is hydrolysed to ADP concurrently. Using kinetic analysis, it was confirmed that the ATP hydrolysis that occurs is 1st order in ATP concentration, while the hydrogen replacement is 2nd order. The ATP and its C8 deuterated analogue were tested against three enzymes shikimate kinase (SK), acetate kinase (AK) and glutamine synthetase (GS) to determine if a kinetic isotope effect (KIE) exists in these systems. With AK and GS, the KIED increased as the KIEH decreased, while with SK the KIED decreased as the KIEH increased as the concentration of the ATP or deuterated analogue increased. Deuteration of imidazole and purine compounds reduced the specific activity of AK or SK at low concentrations in an enzyme-catalysed reaction. From a library of imidazole-containing compounds that inhibited SK, three compounds were selected and their IC50 values were determined on the SK-catalysed reaction. These compounds show a differential potency and efficiency between their protonated and deuterated analogues when compared in a 1:1 mixture. Synthesized purines incorporating three different substituents at N-9 were tested against AK or SK for their ability to lower the specific activity of the enzymes used / Physics / M. Sc. (Physics)

Nature has always remained a constant source of inspiration for chemists for synthesizing natural products, mimicking enzymatic reactions or to construct molecular architectures resembling biological assemblies. With the rapid growth of ‘Supramolecular Chemistry’ along with the advancement of the synthetic methodologies, molecular systems with brand new complexities have been synthesized, alongside the efficacy of weak, reversible non-covalent interactions have also been extensively explored. A number of such forces including hydrogen bonding, solvophobic effect, dynamic covalent interactions and metal-ligand coordination have been exploited to assemble the molecular building blocks and stitch them together to construct discrete ‘self-assembled’ architectures integrated with desired functionalities. Metal-ligand coordination driven self-assembly certainly evolved as one of the most successful approaches for the construction of discrete supramolecular architectures during last two and half decades. The high directionality and reversible nature of certain metal-ligand bonds allow the pre-designing of sophisticated architectures which can be successfully obtained by ‘error corrections’ via a thermodynamically controlled self-assembly process. Numerous aesthetically elegant two dimensional (2D) and three dimensional (3D) metallosupramolecular architectures have been constructed which have been studied for various potential applications including guest encapsulation, catalysis, sensing, optoelectronics, drug delivery, protection of reactive species etc. Construction of such molecular architectures uses symmetric and rigid building blocks which strictly preserves their geometrical coding and thus finally determines the fate of the self-assembly. Pyridyl-based donors have been extensively used due to their well-behaved coordination with transition metal ions. Interestingly, imidazole based donors remained almost unexplored for such purpose mainly due to the rotational flexibility of imidazole moieties owing to the lack of -electron delocalization with the aromatic backbone, which makes pre-designing an architecture extremely difficult. However, this unpredictability can lead to the formation of unprecedented molecular architectures. Furthermore, the conventional rigid ‘acceptors’ used in the ‘directional bonding approach’ always results in the formation of rigid assemblies, which cannot be utilized for the construction of smart molecular machine based applications. In this context, incorporation of restricted rigidity in the building blocks can be a convenient approach to construct versatile and flexible supramolecular architectures. Although flexible donors are quite common in coordination-driven self-assembly, the use of flexible metal acceptor is scarcely Highly symmetric spherical assemblies of square planer Pd(II) and Pt(II) ions are one of the most extensively studied metallosupramolecular architectures owing to their topological similarity with the spherical virus capsids. Unfortunately, none of the reported molecular spheres are soluble in water which restricts their applications in aqueous media. On the other hand, most of the metallosupramolecular architectures cannot be used for redox based applications as the oxidation state of the associated metal ions must be kept unaltered. Although, assemblies constructed mainly by the ferrocene containing acceptors are shown to be exhibiting redox property, the donor inherited redox active metallosupramolecular systems are extremely rare. Discrete 3D metallosupramolecular cages have been extensively studied as synthetic hosts where the hydrophobic pockets have been utilized as safe shelter for reactive species, for catalyzing chemical transformations, tuning electronic and optical properties of guest molecules, as delivery vehicle for drug molecules etc. However, a major drawback of many such 3D cages is associated with their closed-shell topology, where the large cavities are accessible though relatively much smaller apertures which prevent larger guest molecules to enter inside. So, an interesting finding in this field would be to construct molecular hosts with larger apertures. Picric acid (PA) is a strong organic acid and like many other polynitroaromatic compounds, it is a powerful explosive. In addition, it has large scale industrial application for the synthesis of dyes and pharmaceuticals. However, PA has potential health hazards and it is a water pollutant owing to its high aqueous solubility. Thus, the development of selective receptors which can efficiently interact with PA and detect it at very lower concentration is an appealing field of research. Chapter 1 briefly discusses the history of supramolecular chemistry and the concept of ‘self-assembly’ along with the several synthetic methodologies for the construction of discrete supramolecular architectures. It also includes a brief discussion on the various design approaches to construct 2D and 3D molecular architectures by metal-ligand coordination which is followed by an account on some of the important applications of such metallosupramolecular architectures. At the end, a small introduction on the fluorescence-based detection techniques for PA has also been included. Chapter 2A accounts for the exploration of two linearly substituted benzene bisimidazole donors L1 and L2 for coordination-driven self-assembly. L1 and L2 possesses different ‘natural’ donor angles as the imidazole moieties in L2 are twisted heavily with respect to the phenyl plane due to the steric hindrance exerted by the methyl groups. Interestingly, while the self-assembly of L1 with [cis-(tmeda)Pd(NO3)2] (tmeda = N,N,Nꞌ,Nꞌ-tetramethylethane-1,2-diamine) exclusively formed a [3+3] molecular triangle, the self-assembly of L2 yielded a [4+4] molecular square as the major product with the same acceptor. In addition, similar treatment with the analogous Pt(II) acceptor resulted mixtures of [3+3] and [4+4] assemblies in both cases; however, the [3+3] assembly was the major product in case of L2. These contradictory product distributions in case of L2 with analogous Pd(II) and Pt(II) acceptors could be corroborated by the delicate balance between the entropic and enthalpic contributions. Scheme 1. Self-assembly of L1/L2 with [cis-(tmeda)Pd(NO3)2] and [cis-(tmeda)Pt(NO3)2], respectively. Furthermore, the reactions of L1 and L2 with a 0º bisplatinum acceptor, viz. AntPt yielded the expected [2+2] macrocycles (8 and 9), respectively. However, the interesting observations Scheme 2. Self-assemblies of L1 and L2 with the 0º bisplatinum acceptor AntPt. obtained from the variable temperature NMR studies suggested the existence of a mixture of inter-convertible conformational isomeric structures of 9. Chapter 2B describes the synthesis of a novel semi-rigid bisplatinum acceptor bisPt-NO3 based on benzil backbone for the construction of flexible metallamacrocycles. The benzil group was selected due to its unique rotational flexibility along the benzyl C-C bond which can generate a wide range of bite angles to make it compatible with the variety of donors of diverse shapes and sizes. The acceptor was successfully self-assembled with four different bisimidazole donors (L1-L4) to yield corresponding [2+2] metallamacrocycles (M1-M4) which were characterized by multinuclear NMR and ESI-MS spectrometry; and their structures were elucidated by semi-empirical geometry optimizations. Scheme 3. Self-assembly of [2+2] metallamacrocycles M1-M4 by a semi-rigid bisplatinum acceptor bisPt-NO3. Chapter 3 discusses the synthesis of the very first example of a water soluble molecular sphere MC-1 by the self-assembly of square planar Pd(II) ions with a flexible cationic tritopic donor La(NO3)3 containing 4,4-bispyridyl arms. The structural flexibility of La(NO3)3 makes it capable of binding with metal ions in its syn- or anti-conformations which was also experimentally observed in the structures of the three newly synthesized coordination polymers, viz. Ag-CP, Zn-CP and Cd-CP constructed by using La(NO3)3 as (co)ligand. Finally, the 4:3 self-assembly of [La(NO3)3] and Pd(NO3)2 in aqueous media produced the desired M6L8 type Scheme 4. Self-assembly of the water soluble molecular dice MC-1 from the tricationic tritopic donor La(NO3)3. molecular sphere- MC-1, which contain 36+ overall charges. The compound could be easily solubilized in water after isolation as solid by simple stirring at room temperature. Single crystal X-ray diffraction analysis (SCXRD) revealed the ‘dice’-shaped architecture of MC-1 where the eight faces are occupied by the coordinated Pd2+ ions and the bispyridyl arms and the vertices are occupied by mesityl moieties. MC-1 is stable in aqueous media, however disintegrates in DMSO, as observed by variable temperature NMR experiments. In addition, MC-1 also produced ligand inherited redox signals in cyclic voltammetry experiments. Chapter 4 describes the synthesis of a novel non-symmetric tetraimidazole donor L based on carbazole backbone. The complexity of the donor is associated with the allowed free rotation of the imidazole moieties along with the non-symmetric nature of the carbazole backbone which make L a very unusual donor for coordination-driven self-assembly. The crystal structure of L showed that the presence of the N-Me group caused a greater twisting of the nearby imidazole moieties with respect to the other set of imidazole moieties. The self-assembly of L with [cis-(en)Pd(NO3)2] (en = ethane-1,2-diamine) yielded a mixture of M4L8 and M6L12 type self-assembled products, as evidenced from the ESI-MS spectrometry. However, the DOSY NMR spectra of the product showed a single diffusion coefficient for all the peaks, indicating that both type of assemblies have similar size and hence suggested the formation of a tetrafacial barrel and a cubic architecture. A similar self-assembly of L with [cis-(tmeda)Pd(NO3)2] also produced a water soluble product. ESI-MS spectra in this case only confirmed the formation of a M4L8 assembly- MB-1. SCXRD analysis of the coronene encapsulated complex of MB-1 gave more insights on the sophisticated non-symmetric tetrafacial barrel architecture of MB-1 with large Scheme 5. Construction of the water soluble molecular barrel MB-1 by the self-assembly of a non-symmetric tetraimidazole donor L. rectangular apertures. The centrosymmetric molecule can encapsulate two aromatic guest molecules inside its hydrophobic cavity and was found to be efficiently encapsulating polyaromatic hydrocarbons (PAHs) in aqueous media. In addition, MB-1 has been successfully exploited to carry water insoluble perylene molecule inside HeLa cells for fluorescence imaging purpose without showing significant toxicity. L also formed a water insoluble tetrafacial barrel (MB-2) by self-assembly with [cis-(dppf)Pd(OTf)] (dppf=diphenylphosphino ferrocene) which interestingly has a symmetrical architecture, as evidenced from the SCXRD analysis. The formation of the symmetrical barrel is driven by the steric hindrance between the bulky phenyl groups of the nearby dppf moieties. Chapter 5 reports the study of interactions between picric acid (PA) with a few newly synthesized fluorescent imidazolium salts (S1-S3). The fluorescence titration study of the positively charged receptors with PA showed rapid decrease of the corresponding fluorescence intensities upon gradual addition of PA. The Stern-Volmer plots suggested the involvement of both static and dynamic quenching mechanisms which was further supported by fluorescence lifetime measurements, NMR and UV-Vis spectroscopic analyses. The values of the Stern-Volmer constants (Ksv) reflected strong receptor-PA binding. The quenching efficiency calculations in the presence of several other analytes proved that the receptors are highly selective for PA in both aqueous and non-aqueous media. The mode of interactions in solid state was investigated by the crystal structure analysis of the [S1PA] complex. 1H NMR spectra of the same complex indicated strong interaction between the imidazolium moieties of the receptor Scheme 6. The fluorescent imidazolium salts based receptors S1-S3 and the florescence titration plot for S1 with PA. Inset: the solutions of S1 and (S1+PA) in DMSO under UV light. with PA in solution; however, no significant interaction of PA with the anthracene moieties was observed in solution as we well as in the solid state. Also the quenching efficiencies and the Ksv values were correlated with the positive charge(s) present on the receptors with the help of two newly synthesized mono-positive receptors S4 and S5.

Die vorliegende Dissertation beschäftigt sich mit der Synthese, der Charakterisierung und der Anwendung neuartiger Phosphane in homogenkatalytischen Reaktionen. Dabei wurden die Ferrocenyl- und Ferrocenylethinylphosphan-Palladium und Ferrocenylethinylphosphan-Ruthenium Komplexe in der Palladium-vermittelten Mizoroki-Heck- und Suzuki-Miyaura-Reaktion sowie der Ruthenium-katalysierten Synthese von β-Oxopropylestern verwendet. Der Schwerpunkt lag dabei auf der Untersuchung des Einflusses der elektronischen und räumlichen Eigenschaften der Phosphanliganden auf die Aktivität und Produktivität der entsprechenden Katalysatoren in den homogenkatalytischen Reaktionen. Weiterhin beschäftigt sich die vorliegende Arbeit mit der Synthese und Charakterisierung von funktionalisierten (Phosphino)Imidazol und (Phosphino)Imidazolium Salzen und deren Anwendung in der Suzuki-Miyaura-Reaktion. Dabei wurde neben der Untersuchung des Einflusses der Position der Phosphanylgruppe und der unterschiedlichen Substituenten ebenfalls die Auswirkung von elektronenziehenden und -schiebenden Gruppen am Phosphanrest untersucht. Die neutralen Mono- und Diphosphane wurden außerdem in der Kreuzkupplung von Arylhalogeniden und in der Synthese räumlich anspruchsvoller Biaryle verwendet. Des Weiteren wurden die (Phosphino)Imidazolium-Salze als Liganden in der Suzuki-Miyaura-Reaktion in ionischen Flüssigkeiten als Reaktionsmedium angewendet, um die Möglichkeit des Recyclings der Katalysatorphase zu untersuchen.