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Ions play pivotal roles both biologically and environmentally. The effects felt from the impact of ions, much like their relative charge, can be positive or negative. Ions are responsible for catalyzing and executing precise control over many of the essential processes that occur in our bodies. Ions can also be major contributors as environmental pollutants having catastrophic effects. There is a great deal of interest in better understanding the role and effect of ions in the surrounding environments. The ability to study ions of interest relies on efficient recognition and sensing of these targets. The field of supramolecular chemistry is particularly well suited for this task as it utilizes non-covalent molecular interactions in much the same way natural system involving ions operate. Broadly, this body of research seeks to explore the subtle interactions of various targeted ions with supramolecular receptors. This research is an effort to further understand the nature of these interactions for potential recognition and sensing applications as well as better understanding the highly complex systems found in biology. Chapter I provides a brief overview of various mechanisms of ion coordination in supramolecular chemistry and emphasizes some key examples demonstrating the importance of the various types of coordination as it pertains to the research presented herein. Chapter II highlights a unique class of phosphine oxide-based tripodal ditopic receptors and presents studies on their interactions with alkali metals and halides. Chapter III covers the synthesis and study of anionic binding trends for a series of heteroaromatic-containing urea-based receptors and discusses the influence of anion binding on receptor conformation. Chapter IV provides preliminary results on the application of the bipyridal bisurea-based anion receptor, presented in Chapter III, as ligand for metal salts. Chapter V focuses on a series of pyridal bisurea-based receptors with regard to their ability to serve as chloride sensitive probes in cellular environments. This dissertation contains both previously published and unpublished co-authored material. / 10000-01-01

This thesis considers methods which can be employed to increase the mass of copper transferred into and out of the organic phase during the load and strip stages of commercial solvent extraction processes. Conventional 5-alkylsalicylaldoxime reagents transfer 1 mol of divalent copper per 2 mol of ligand in a neutral complex of the type [Cu(L-H)2] via a pH-swing process. New triacidic ligands have been designed which triple the molar transport of copper to form [Cu3(L-3H)2]. Until recently copper recovery by solvent extraction has been confined to oxidic ores which are leached with sulfuric acid. New leaching technologies generate high tenor copper sulfate feed streams from sulfidic ores. The conventional 5- alkylsalicylaldoxime reagents do not work effectively in conjunction with these leach processes as they do not consume the acid which is generated on loading the oxime. To address this problem ditopic zwitterionic ligands have been designed which can transfer both metal cation and attendant anion. These new metal salt reagents are diacidic, therefore not only transfer metal salts but also increase the molar transport relative to the conventional reagents. Equilibrium-modifiers are often added to improve the mass transport efficiency of conventional solvent extraction processes. The nature of their interaction with the species in solution is poorly understood. This thesis investigates their interaction with the free ligands and copper complexes to gain an understanding of their mode of action in order to rationalise the design of future modifiers to optimise recovery efficiencies. Increased molar transport is addressed in Chapter 2. The diacidic ligand 5- methylsalicylaldehyde-pivaloylhydrazide (L2) and its dinuclear copper complex [Cu2(L2-2H)2] were synthesised and characterised to gain an understanding of their speciation in solution. X-ray structural analysis of [Cu2(L2-2H)2] confirmed that the phenolate oxygen atoms bridge the copper centres rather than the amidato oxygen atoms of the hydrazone. Variable temperature magnetic susceptibility data confirm that the copper centres are antiferromagnetically coupled as expected for the Cu-OCu angle (99.6(2)°). An understanding of the coordination geometry of the dinuclear systems lead to design of triacidic ligands. A series of 3-hydrazono- and 3- hydroxyanil- 5-alkylsalicylic acids were synthesised. The prototype ligand 5-methyl 3-octanoylhydrazonosalicylic acid (L6) was demonstrated to triple molar transport and increase mass transport by 2.5 fold. Solvent extraction results indicate that copper is sequentially loaded as pH is increased. The plateaux observed in loading curves suggest formation of stable mono-, di-, and tri-nuclear copper complexes within the pH-ranges 1.75 - 2.75, 3.25 - 4.0 and > 4.25 respectively. The triacidic ligands were also demonstrated to double the molar transport of the conventional salicylaldoximes when used in 1:1 blends by formation of a ternary complex. Chapter 3 describes the incorporation of two tertiary amine groups into diacidic salicylaldehydehydrazone ligands to form dinucleating metal salt extractants. Piperidinomethyl, piperazinomethyl and dihexylamino groups were incorporated into various positions of the ligand including 3- and/or 5- positions of the salicylaldehyde or incorporated into the hydrazone. Solvent extraction results obtained for 3,5- bis((dihexylamino)methyl)salicylaldehyde-octanoic hydrazone (L20) are consistent with transfer of 1 mol of copper sulfate per mol of ligand in the organic phase between pH 2.0 and 2.5. This result is indicative of the formation of [Cu2(L20)2(SO4)2]. Conventional salicylaldoximes are “strong” copper extractants which require concentrated acid electrolyte to efficiently strip the copper from the organic phase. However, as the use of concentrated acid affects the quality of the copper cathodes, oxygen-containing equilibrium modifiers are often added. These facilitate copper stripping without adversely affecting the loading. The affect of 2-ethylhexanol (2- EH) and trioctylphosphine oxide (TOPO) on the extractive ability of 5-toctylsalicylaldoxime (19) in n-heptane is reported. Both are found to decrease copper extraction more under stripping conditions than loading conditions. 2-EH shows little affect at pH greater than 2.5. TOPO does not significantly affect copper loading at pH greater than 3.0. Evidence for the formation of the adduct [Cu(19-H)2)(TOPO)] was obtained from UV/Vis, IR, EPR and sonic spray mass spectrometry.

This thesis describes selected reactivity studies of the N-heterocyclic carbene, IPr, towards a range of main group compounds. The synthesis and characterisation of sixty-three compounds, all of which incorporate IPr as a ligand in one of three coordination modes, are detailed herein. The deprotonation of IPr allowed for the isolation of an anionic source of the aIPr: ligand which was synthesised as a novel potassium salt and along with the previously reported lithium salt, was employed in reactions with group 12 and 14 bis(trimethylsilyl)amides and tetrahalides. The further chemistry of such novel products was investigated towards both electrophilic and nucleophilic reagents making use of both the pendant nucleophilic carbene functionality and the electrophilic main group centre. An alternative route to such species was investigated by the spontaneous isomerisation of IPr in the coordination sphere of group 14 tetrabromides and group 15 tribromides. The scope of this reactivity was subsequently investigated and was found to provide a simpler route to access the abnormal coordination mode of IPr. The aIPr ligand which is generated may be deprotonated by additional IPr thereby affording aIPr: ligands. The addition of halide abstracting agents allowed for the synthesis of cationic species stabilised by the coordination of either IPr or aIPr ligands. A unique, spontaneous reductive coupling of two phosphorus centres was discovered to take place upon heating a THF solution of (IPr)PBr₃. This allowed for the isolation of a bromide bridged P–P bond with reduced phosphorus centres. This facile reduction chemistry was further explored by reaction with mild reducing agents which provide access to low oxidation state phosphorus compounds in high yields. This chemistry was found to be possible (and more effective) due to the presence of the weaker phosphorus bond to bromine relative to the commonly employed chlorine ligands.

This thesis deals with the design and syntheses of chiral,enantiopure pyridinecontaining ligands and their applicationsin asymmetric catalyis. Chiral pyridyl pyrrolidine ligands and pyridyl oxazolineligands were synthesized and employed in thepalladium-catalysed allylic alkylation of 1,3-diphenyl-2-propenyl acetate with dimethyl malonate. Theinfluence of the steric properties of the ligands wereinvestigated. Ditopic ligands, containing crown ether units as structuralelements, were synthesized and some of the ligands were used asligands in the palladiumcatalysed allylic alkylation of1,3-diphenyl-2-propenyl acetate with dimethyl malonate. A smallrate enhancement was observed, compared with analogous ligandslacking the crown ether unit, when these ditopic ligands wereused in dilute systems. A modular approach was used to synthesize chiralenantiomerically pure pyridyl alcohols and C2-symmetric2,2’-bipyridines, with the chirality originating from thechiral pool. Electronic and steric properties of the compoundswere varied and they were used as ligands in theenantioselective addition of diethylzinc to benzaldehyde. Thesense of asymmetric induction was found to be determined by theabsolute configuration of the carbinol carbon atom. Theelectronic properties of the ligands had a minor influence onthe levels of enantioselectivity induced by the ligands. Chiral pyridyl phosphinite ligands and pyridyl phosphiteligands were synthesized from the pyridyl alcohols andevaluated as ligands in palladiumcatalysed allylic alkylations.With the phosphinite ligands, the sense of chiral induction wasfound to be determined by the absolute configuration of theformer carbinol carbon atom. A kinetic resolution of theracemic starting material was observed with one of thephosphite ligands. Moderate enantioselectivities wereachieved. <b>Kewords:</b>asymmetric catalysis, chiral ligand, chiralpool, oxazoline, crownether, ditopic receptor, bipyridine,pyridyl alcohol, modular approach, P,Nligand, diethylzinc,allylic alkylation.

<p>This thesis deals with the design and syntheses of chiral,enantiopure pyridinecontaining ligands and their applicationsin asymmetric catalyis.</p><p>Chiral pyridyl pyrrolidine ligands and pyridyl oxazolineligands were synthesized and employed in thepalladium-catalysed allylic alkylation of 1,3-diphenyl-2-propenyl acetate with dimethyl malonate. Theinfluence of the steric properties of the ligands wereinvestigated.</p><p>Ditopic ligands, containing crown ether units as structuralelements, were synthesized and some of the ligands were used asligands in the palladiumcatalysed allylic alkylation of1,3-diphenyl-2-propenyl acetate with dimethyl malonate. A smallrate enhancement was observed, compared with analogous ligandslacking the crown ether unit, when these ditopic ligands wereused in dilute systems.</p><p>A modular approach was used to synthesize chiralenantiomerically pure pyridyl alcohols and C2-symmetric2,2’-bipyridines, with the chirality originating from thechiral pool. Electronic and steric properties of the compoundswere varied and they were used as ligands in theenantioselective addition of diethylzinc to benzaldehyde. Thesense of asymmetric induction was found to be determined by theabsolute configuration of the carbinol carbon atom. Theelectronic properties of the ligands had a minor influence onthe levels of enantioselectivity induced by the ligands.</p><p>Chiral pyridyl phosphinite ligands and pyridyl phosphiteligands were synthesized from the pyridyl alcohols andevaluated as ligands in palladiumcatalysed allylic alkylations.With the phosphinite ligands, the sense of chiral induction wasfound to be determined by the absolute configuration of theformer carbinol carbon atom. A kinetic resolution of theracemic starting material was observed with one of thephosphite ligands. Moderate enantioselectivities wereachieved.</p><p><b>Kewords:</b>asymmetric catalysis, chiral ligand, chiralpool, oxazoline, crownether, ditopic receptor, bipyridine,pyridyl alcohol, modular approach, P,Nligand, diethylzinc,allylic alkylation.</p>

Lanthanide elements display many remarkable and exciting properties which explain their widespread use in a number of very important biomedical tools like efficient MRI contrast agents or luminescent probes for highly sensitive assays of bioanalytes amongst other fields of application. In this context, the aim of the present work was to prepare and characterize lanthanide complexes of two ligands that feature a linear or a macrocyclic chelating unit compactly grafted onto a 1,10-phenanthroline derived moiety (phenDTPA and PhenHDO3A). The ditopic nature of the ligands allows the selective incorporation of a d6 metal ion and a lanthanide one in close proximity. The resulting rigid heterobimetallic supramolecular species show useful properties and constitute potential MRI contrast agents or new luminescent compounds depending on the type of the lanthanide and transition metal ions employed: for example, the selfassembly process of gadolinium(III) chelates around an iron(II) ion brings a remarkable increase of their relaxivity, a key parameter for use in MRI. On the other hand, association of a ruthenium and and a near infrared emitting 4f ion like ytterbium(III) gives mixed d-f structures able to harvest visible light and convert it into near infra-red signal. Visible light luminescent pH probes were also obtained with Eu3+ or Tb3+ phenHDO3A complexes.

Ce travail s'inscrit dans le cadre de la chimie supramoléculaire, domaine s'intéressant à l'étude d'édifices moléculaires liés par des interactions non-covalentes, fréquemment rencontrés dans le monde du vivant. Afin de mieux comprendre les phénomènes de complexation, de nombreux récepteurs moléculaires synthétiques ont été développés depuis ces cinquante dernières années. Dans le cadre de la reconnaissance moléculaire, les calix[6]arènes s'avèrent être des plateformes idéales puisqu'ils sont aisément fonctionnalisables et possèdent une cavité hydrophobe propice à l'inclusion de petites molécules organiques. D'ailleurs de nombreux récepteurs calix[6]aréniques ont déjà été développés et ont été étudiés pour leur aptitude à complexer des molécules neutres, des anions, des paires d'ions ou des ions métalliques. Cependant, ils souffrent de certaines limitations puisqu'ils ne sont pas hydrosolubles et sont difficilement post-fonctionnalisables limitant de ce fait leur applicabilité. Nous nous sommes donc intéressés à la synthèse de récepteurs calix[6]aréniques fonctionnalisés ainsi qu'à l'étude de leurs propriétés réceptrices vis-à-vis d'entités chargées ou de molécules neutres. Les études de ces systèmes ont été réalisées essentiellement par spectroscopie de Résonance Magnétique Nucléaire (RMN).<p>Dans le cadre de ce travail, des récepteurs ditopiques mono- et trisfonctionnalisés de type calix[6]cryptamide ont tout d'abord été développés. Ces récepteurs présentent un motif trenamide qui constitue un second site de reconnaissance, distinct mais proche du premier formé par la cavité calix[6]arénique. Ces récepteurs se sont révélés capables de complexer les molécules neutres polaires ainsi que des entités chargées avec une grande sélectivité en milieu aprotique mais également en présence d'un solvant protique. Le chapeau trenamide étant relativement contraint et bien préorganisé, il assure un fort effet chélate et permet une sélectivité de taille pour l'anion fluorure. La proximité des deux sites de reconnaissance ainsi que la sélectivité pour l'anion fluorure permettent à ces récepteurs de reconnaître des ammoniums sous forme de paires d'ions de contact uniquement avec le fluorure comme partenaire anionique. Les résultats obtenus ont démontré que l'introduction de fonctionnalisations soit au niveau du chapeau trenamide, à proximité du site de reconnaissance, soit au niveau du petit col du calix[6]arène n'inhibait pas les propriétés de complexation de ces récepteurs. Les premiers essais d'introduction de groupes hydrosolubilisants ont alors été réalisés et se sont révélés très prometteurs. En effet, l'introduction de groupements PEG sur un calix[6]cryptamide trisfonctionnalisé a permis de démontrer l'aptitude de ce récepteur à complexer des molécules neutres en milieu aqueux (CD3OD/D2O).<p>Dans un second temps, des récepteurs mono- et trisfonctionnalisés de type calix[6]tren ont été développés. Les études préliminaires réalisées ont permis de mettre en évidence que, comme le calix[6]tren non fonctionnalisé, ces récepteurs étaient capable de complexer de petites molécules organiques lorsqu'ils sont polarisés, soit sous leur forme per-protonnée soit sous la forme d'un complexe métallique (Zn2+ ou Cun+). <p><p>L'ensemble de ces travaux a ainsi permis de valider la stratégie de synthèse visant à introduire des bras fonctionnels sur des récepteurs ditopiques calix[6]aréniques et de démontrer que ces nouveaux récepteurs fonctionnalisés conservaient des propriétés de reconnaissance. Ces travaux permettent donc d'envisager de multiples applications pour ce type de récepteurs.<p>This work falls within the field of supramolecular chemistry, a field concerned with the study of molecular structures linked by non-covalent interactions. Such weak interactions are frequently encountered in the living world and in particular in molecular recognition processes. In order to better understand and exploit these recognition processes, many synthetic molecular receptors have been developed over the last fifty years. In this regard, calix[6]arenes have proved to be ideal platforms because they can be easily functionalized and they possess a hydrophobic cavity suitable for the inclusion of small organic molecules. Hence, many calix[6]arene based receptors have been studied for their ability to complex neutral molecules, anions, ion pairs or metal ions. However, most of these receptors suffer from major limitations that limit their applicability: they are not water soluble and hardly post-functionalizable. In the frame of this thesis, we were therefore interested in the synthesis of functionalized calix[6]arene based receptors and in the study of their host-guest properties toward charged species or neutral molecules. Studies of these host-guest systems have been carried out mainly by Nuclear Magnetic Resonance spectroscopy (NMR).<p><p>First, mono- and trisfunctionalized ditopic receptors based on a calix[6]cryptamide skeleton were synthesized. These receptors possess two binding sites in close proximity: a trenamide subunit and the calix[6]arene cavity. They have proved to be capable of complexing neutral polar molecules as well as charged species with high selectivity in aprotic solvents but also in a protic environment. The trenamide cap being relatively constrained and well pre-organized, it provides a strong chelate effect and allows a selectivity of size for the fluoride anion. Remarkably, the proximity of the two recognition sites allow these receptors to recognize ammonium ions in the form of contact ion pairs but only with a fluoride anion as the partner. The results have shown that the introduction of functionalizations at the trenamide cap or at the narrow rim of the calix[6]arene do not inhibit the complexation properties of these receptors. First attempts in order to introduce water-solubilizing groups have been undertaken and promising results have been obtained. Indeed, the introduction of PEG groups on a trisfunctionalized calix[6]cryptamide has led to a receptor able to complex neutral molecules in an aqueous environment (CD3OD/D2O).<p><p>In a second step, mono- and trisfunctionalized receptors derived from calix[6]tren have been synthesized. Preliminary studies have highlighted that, similarly to the parent calix[6]tren, these receptors are able to complex small organic molecules when they are polarized either in their per-protonated form or in the form of a metal complex (Zn2+ or Cun+).<p><p>All this work validates the synthetic strategy that consists of introducing functional arms on ditopic calix[6]arene based receptors and opens new perspectives for the elaboration and study of molecular receptors in an aqueous environment. <p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished