La thèse est une étude des propriétés photophysiques et photochimiques de systèmes contenant la molécule sulfonylcalix[4]arène, membre de la famille des thiacalixarènes. Une série d'études dans notre laboratoire a révélé qu'un complexe agrégat tétranucléaire de manganèse(II) avec le ligand para-tert-butylsulfonylcalix[4]arène (thiaSO2) montrait une forte émission rouge sous l'action de lumière bleu. Cette découverte surprenante est la base de cette étude doctorale.Le premier chapitre est une revue de la littérature concernant les thiacalixarènes et leurs complexes métalliques. La synthèse et les modifications de ces molécules seront décrites, ansi que leurs propriétés fondamentales.La deuxième partie se concentre sur les propriétés de luminescence. Afin de proposer une explication mécanistique, la réponse de l'émission provenant du complexe (K)[Mn4(thiaSO2)2F] (2) a été étudiée sous des conditions variables de pression, température, pression d'O2 … L'hypothèse que ces systèmes sont capables de produire l'oxygène singulet sera faite.Le troisième chapitre concerne les photoréactions de systèmes en solution des complexes de manganèse(II). La photo-oxydation des ions Mn2+ en Mn3+ a été étudiée et les divers facteurs contribuants à ce processus seront discutés. Le rôle important de l'oxygène et sa transformation en espèces réactives, l'effet du solvant et du pH du milieu de réaction, et l'importance des matériaux de départ, sont confirmés ; nous proposons un mécanisme réactionnel basé sur ces données et la photoréactivité du composé organique calculée par une méthode théorique.La dernière partie montrera la préparation et la caractérisation d'espèces hybrides organique-inorganique par l'insertion d'agrégats [Mn4(thiaSO2)2F]- dans des matériaux LDH (« Hydroxyde Double Lamellaires »). Ces hybrides sont réalisés par des méthodes de chimie douce. Les études préliminaires sur la structure, la luminescence, et la photoréactivité des produits ont été faites. Finalement, un essai a été fait afin de tester la capacité des matériaux hybrides à agir comme photocatalyseur pour l'oxydation de molécules simples / This thesis is a study of the photophysical and photochemical properties of systems containing the molecule sulfonylcalix[4]arene, a member of the thaicalixarene family. A series of studies in our laboratory revealed that a tetranuclear cluster complex of manganese(II) with the ligand para-tert-butylsulfonylcalix[4]arene (thiaSO2) displayed strong red emission under the action of blue light. This surprising discovery became the basis for this doctoral study.The first chapter is a review of the literature concerning thiacalixarenes and their metal complexes. The syntheses and modifications of these compounds will be described, as well as their fundamental properties.The second part is dedicated to the properties of luminescence. In order to propose a mechanistic explanation, the response of the emission arising from the complex (K)[Mn4(thiaSO2)2F] (2) has been studied under varying conditions of pressure, temperature, O2 partial pressure … The hypothesis that these systems are capable of producing singlet oxygen will be made.The third chapter is concerned with photoreactions of these systems in solution. The photo-oxidation of Mn2+ ions into Mn3+ ions was investigated and the various contributing factors to this process will be discussed. The important role of oxygen and its transformation into reactive species, the effect of the solvent and the pH of the reaction medium, and the importance of the starting material, are all confirmed; we will propose a reaction mechanism based on both these data and the photoreactivity inherent to the organic compound calculated by a theoretical method.The final part will show the preparation and characterisation of organic-inorganic hybrid species by the insertion of [Mn4(thiaSO2)2F]- aggregates into LDH (“Layered Double Hydroxide”) materials. These hybrids were obtained by soft chemistry methods. Preliminary investigations of the structure, the luminescence, and the photoreactivity of these products have been made. Finally, an attempt was carried out to test the capacity of these hybrid materials to act as photocatalysts for the oxidation of simple molecules

Doctor of Philosophy / Department of Chemistry / Christopher J. Levy / 2-Formylbenzoquinoline and a selection of novel chiral bis(pyridine-imine) and bis-amide ligands derived from (1R,2R)-cyclohexanediamine and (R)-[1,1’-binaphthalene]-2,2’-diamine have been synthesized and thoroughly characterized. Subsequently, their coordination chemistry has been investigated. Metallation with Zn(II), Ni(II) and Fe(II) has resulted in the formation of a series of helical complexes, some of which exhibit unusual coordination modes. Bis(imine-pyridine) ligands were found to form dinuclear complexes upon reaction with ZnCl2. In one case, the use of Zn(CF3SO3)2 resulted in the formation a single stranded monohelix, after the ligand had undergone a reduction at one imine bond. The use of NiI2 as the metal salt resulted in the formation of penta-coordinate complexes with N3-coordination and helical dinuclear complexes with bridging iodo ligands. Ni(CF3SO3)2 was also used, this resulted in the formation of a double stranded mononuclear complex. The ligand, in this case was hydrolyzed to yield a tridentate ligand, subsequently two of these new ligands coordinate to one metal center to form the complex. Bis-amide ligands were reacted with FeCl2 and Fe(CF3SO3)2 to form complexes with various different colors. In all but one case, several attempts to structurally characterize the Fe(II) complexes were unsuccessful. Suitable crystals of this complex revealed a double stranded helicate complex that coordinates through carbonyl oxygens rather than amide nitrogens. The work described herein, is an account of the synthesis, characterization and study of a new family of tetradentate nitrogen donor ligands and their respective transition metal complexes.

This work was initially launched to study the synthesis of low-valent group 13 compounds bearing the bis(imino)pyridine ligand framework. Since its inception, this project has grown beyond the boundaries of group 13 to include low valent tin, silver, and rhenium. Alongside the reports of novel coordination compounds, we utilized computational chemistry to uncover unprecedented interactions which challenge conventional concepts of bonding. Synthesis, characterization, and complimentary computational studies are presented herein. Chapter 1 presents a historical overview of the bis(imino)pyridine ligand as well as our synthetic methodology and characterization of new ligand variants we have contributed to the literature. Chapter 2 presents the synthesis of a series of In(I) and In(III) bis(imino)pyridine complexes with varied sterics. Ligand-metal interaction and effect of ligand steric bulk on complex stability, as well as computational studies highlighting weak covalent interactions will be discussed. Chapter 3 presents the synthesis of Ga(III) bis(imino)pyridine complexes. Reactivity with “GaI” synthon as well as varied-stoichiometry one-pot synthesis attempts to generate low valent Ga-bis(imino)pyridine complexes will be discussed. Chapter 4 presents the synthesis of a series of Tl(I) bis(imino)pyridine complexes with varied sterics analogous to the approach taken with indium(I). Unprecedented weak ligand-metal as well as Tl-arene interactions will be discussed. Chapter 5 presents the synthesis of a series of Sn(II) bis(imino)pyridine complexes with varied sterics and halide substituents. Preferential cation-anion pair formation and attempted reactivity will be discussed. Chapter 6 presents the synthesis of a series of Ag(I) bis(imino)pyridine complexes with varied sterics. Resulting ligand-metal interactions as well as reactivity towards Lewis basic donor ligands will be discussed. Chapter 7 presents the synthesis of first crystallographically authenticated examples of rhenium(I) pincer complexes utilizing the bis(imino)pyridine ligand. Chapter 8 presents a general conclusion to the work.

In order for molecular magnetic materials to become applicable, they must retain their magnetisation at reasonable temperatures, which can be achieved with high energy barriers for spin reversal and high blocking temperatures. In the field of Single-Molecule Magnets (SMMs), over the last decade, the main focus has shifted from large spin complexes to highly anisotropic systems which have displayed record energy barriers. There are two main methods of increasing magnetic anisotropy in a complex: i) Choosing a metal ion that boasts high magnetic anisotropy then coupling two such ions through magnetic interactions to induce large global anisotropy, and ii) maintain a low spin or use a mononuclear complex while minimising quantum tunnelling of the magnetisation by controlling the geometric features of the metal ion. Both strategies are equally valid and have been explored in this thesis using dinuclear lanthanide as well as mononuclear 3d complexes. In the pursuit of high-barrier SMMs via alignment of anisotropy axes, two dinuclear, quadruple-stranded helicates and one mesocate were isolated and are described in detail herein, both structurally and magnetically. Furthermore, theoretical calculations have been performed to determine the energies of Kramers doublets on each DyIII centre to derive magneto-structural correlations. To induce magnetic interactions between DyIII ions, a centrosymmetric dinuclear SMM was synthesised. Investigation of the crucial DyIII…DyIII interaction as well as its effect on the quantum tunnelling of the magnetisation has been carried out using ab initio calculations and magnetic dilution studies. Using the same system, a method of greatly enhancing the energy barriers in SMMs has been developed. It involves modifying the coordinating ligands to include electron withdrawing groups in order to yield more anisotropic metal ions. The energy barrier for spin reversal has been increased 7-fold in one case. While lanthanide chemistry has proven to be quite versatile and promising, a new branch of nanomagnets is currently being pursued: mononuclear 3d complexes as SMMs. The advantages of 3d metals include high anisotropy per ion, low spin (as anisotropy decreases with increasing spin), well-understood electronic structures and clear correlations between geometry and magnetic anisotropy. The structural and magnetic properties of three complexes based on CoII and terpyridine ligands as well as a seven-coordinate CoII complex with positive anisotropy are discussed at length. The unique slow relaxation dynamics and spin crossover behaviour has been followed using DFT and ab initio calculations, as well as EPR and magnetic dilution studies. Overall, this thesis describes the efforts taken to synthesise high-barrier nanomagnets through understanding the origins and mechanisms of slow magnetic relaxation in both lanthanide and 3d metal complexes.

Les anions polyaminocarboxylates ont été identifiés comme des composés d'intérêt pour les opérations de séparation des actinides, dans la migration des actinides dans l'environnement et dans la radiotoxicologie humaine. La caractérisation structurale de complexes formés entre les actinides et les ligands polyaminocarboxylates est essentielle pour une meilleure compréhension des interactions actinides – ligands. Parmi les anions polyaminocarboxylates, le macrocycle DOTA (acide 1,4,7,10-tétraazacyclododécane-tétraacétique) est décrit comme un agent complexant très fort des lanthanides(III), mais a été très peu étudié avec des actinides. L'objectif de ce travail de thèse est de décrire les complexes formés entre les actinides (III) et (IV) et le ligand DOTA et de les comparer avec les complexes de lanthanides(III). Pour cela, une approche a été mise en place afin de caractériser les complexes par des techniques analytiques complémentaires (spectrophotométrie, spectrométrie de masse à ionisation par électrospray, RMN, EXAFS, électrochimie) mais également par des calculs de chimie théorique pour aider à l'interprétation des données expérimentales.La formation d'un complexe de stœchiométrie 1:1 est observée avec les actinides(III) (américium et plutonium) comme dans le cas des lanthanides(III) : il y a formation rapide d'espèces intermédiaires qui évoluent lentement vers la formation d'un complexe limite. Au sein de ce complexe, le cation se trouve à l'intérieur de la cavité formée par le macrocycle DOTA, comme dans le cas des lanthanides(III). Quatre atomes d'azote et atomes d'oxygène des fonctions carboxylates sont impliqués dans la sphère de coordination du cation. Néanmoins, des différences sont observées sur les longueurs de liaisons formées entre le cation et les atomes d'azote (les liaison sont légèrement plus courtes dans le cas des complexes d'actinides) ainsi que sur la cinétique de complexation qui est légèrement plus rapide pour les actinides(III) que pour les lanthanides(III) de rayon ionique équivalent. Le même comportement en solution est observé lors de la complexation des actinides(IV) (uranium, neptunium et plutonium) à l'exception du thorium : il y a formation lente d'un complexe de stœchiométrie 1:1 (actinides(IV):ligand) dans lequel le cation se trouve à l'intérieur de la cavité formée par le ligand, bien que la cinétique de complexation des actinides (IV) soit plus lente que celle des actinides(III). L'étude des complexes thorium(IV)-DOTA montre la présence de complexes de stœchiométrie 1:1 et 1:2 en solution, pour lesquels seules les fonctions carboxylate du ligand seraient impliquées dans la complexation.Enfin, une première estimation de la constante de stabilité des complexes plutonium(IV)-DOTA, effectuée par des mesures électrochimiques, indique que les complexes d'actinides(IV) sont environ 10 ordres de grandeurs plus stables que les complexes d'actinides(III), comme ce qui a pu être observé avec d'autres polyaminocarboxylates. / The polyaminocarboxylate anions have been identified as compounds of interest in the operations of actinide separation, in actinide migration in the environment and in human radiotoxicology. The structural characterization of complexes formed between actinides and polyaminocarboxylates ligands is essential for a better understanding of actinide-ligands interactions. Among the polyaminocarboxylate anions, the DOTA ligand (1,4,7,10-tetraazacyclododecane tetraacetic acid) is described as a very strong complexing agent of the lanthanides(III), but has been little studied with actinides. The objective of this thesis is to describe the complexes formed between the actinides (III) and (IV) and the DOTA ligand, and compare them with the lanthanide complexes. For this, an approach has been introduced to characterize the complex by complementary analytical techniques (spectrophotometry, electrospray ionization mass spectrometry, NMR, EXAFS, electrochemistry), but also by calculations of theoretical chemistry to help the interpretation of the experimental data. The formation of a 1:1 complex is observed with the actinides(III) (plutonium and americium) as in the case of lanthanides(III): rapid formation of intermediate species which evolves slowly towards the formation of a limit complex. Within this complex, the cation is located inside the cavity formed by the ligand. Four nitrogen atoms and oxygen atoms from the carboxylate functions are involved in the coordination sphere of the cation. However, differences were observed in the bond lengths formed between the cation and the nitrogen atoms (the bonds are somewhat shorter in the case of actinide complexes) as well as the complexation kinetics, which is slightly faster for the actinides(III) than for lanthanide(III) ions of equivalent radius. The same behavior was observed in solution upon complexation of actinides(IV) (uranium, plutonium and neptunium): slow formation of a 1:1 complex (actinide(IV):ligand) in wherein the cation is located inside the cavity formed by the macrocycle DOTA, although the kinetics of actinide(IV) complexation is slower than for the actinides(III) complexation. Nevertheless, the study of thorium(IV)-DOTA complexes shows differences since 1:1 and 1:2 complexes in solution are detected, and where only the carboxylate functions are involved in the coordination sphere of the cation. Finally, an initial estimate of the stability constant of the plutonium(IV)-DOTA complexes by electrochemical measurements indicates that complexes of actinide(IV) are approximately 10 orders of magnitude more stable than the complex of actinides(III), as previously observed with other polyaminocarboxylate anions.

A collection of studies are reported that focus on the examination of exchange interactions in complexes containing paramagnetic ions with a large magnetic anisotropy. A number of complementary techniques are used to analyse the complicated systems that arise, including high-field high-frequency electron paramagnetic resonance, inelastic neutron scattering, SQUID magnetometry, and ab initio calculations. The nuclearity of the complexes ranges from dimetallic, to trimetallic, to octametallic. A family of five water- and carboxylate-bridged nickel(II) dimetallics are the focus of a magneto-structural correlation study that succeeds in measuring the magnitude of the exchange interaction despite dominating effects from large zero-field splitting effects. Similar work is reported for four cobalt(II) analogues of these compounds, with the relationship between exchange interactions and geometry also being probed by pressure INS. Charge density studies that combine high resolution X-ray and neutron diffraction studies are reported on cobalt and nickel analogues from the same family of dimetallics, revealing strong evidence for non-direct exchange. A family of four trimetallic triangle complexes containing two nickel(II) ions and one chromium(III) ion bridged by a central fluoride and a total of six carboxylates are reported, and the exchange interactions are elucidated from a global model that accounts for the low-field magnetic, heat capacity, and EPR data. Two new octametallic vanadium(III) wheels—where each pair of adjacent metals are bridged by a fluoride and two carboxylates—are reported along with preliminary results from magnetic measurements and solid state proton NMR spectra, which reveal significant field-dependent effects arising from level crossings at high fields.

O entendimento das propriedades de complexos metálicos é de fundamental importância para o desenvolvimento de fármacos. No entanto, tanto do ponto de vista experimental quanto no de modelagem teórica, ainda temos muitas dificuldades de simular e mensurar as mudanças que a complexação com um metal causa em um composto. Este trabalho apresenta estudos de simulacões ab initio de complexos de Epiisopiloturina com Cu e Zn. Foram realizadas otimizações de estrutura, simulaçoes de espectroscopia vibracional, NMR e EPR além de estudos de reatividade. Obtivemos uma geometria otimizada condizente com a da forma cristalizada. Além disso, os resultados espectroscópicos mostram que as estruturas dos com plexos permanecem intactas em solução. Por fim, os estudos de reatividade conrmam que o complexo de Cobre aumenta a reatividade da molécula. / Understanding the properties of metal complexes is fundamental goal in the development of drugs. However, both from the experimental point of view and theoretical modeling, many diculties in the simulation and evaluatio of the changes that the metal causes upon complexation still remains. This work presents ab initio computational simulations of Epiisopiloturin com plexes with Cu and Zn. We make structural optimizations, simulations of vibrational spectroscopy, NMR and EPR, as well as reactivity studies. We obtain an optimized geometry that corresponds to that of the crystallized form. In addition, the spectroscopic results conrm that the complexes remain intact in solution. Finally, the reactivity studies conrm that the copper complex increases the reactivity of the molecule.

Ce travail de thèse traite de la synthèse de porphyrines à une ou deux anses (6, 11, 8i and 14i) greffées sur les positions méso adjacentes 5,10 et 15,20 et portant une fonction acide carboxylique suspendue avec ou sans un autre groupement fonctionnel (cyano, pyridine) en position alpha. Cette conformation génère une flexibilité de l'anse avec deux positions clairement identifiées de l'acide carboxylique (intérieure/extérieure). Ainsi la synthèse et la caractérisation des composés sont discutées en détails puis la coordination des ligands 6, 11, et 8i avec les métaux Zn(II), Hg(II), Pb(II) et Bi(III) est décrite. Dans le cas du zinc, cation penta-coordiné en géométrie pyramidale à base carrée, ce dernier est stabilisé soit par le groupement acide carboxylique intramoléculaire soit par une molécule de solvant exogène (DMSO ou H2O). Dans le cas du mercure, des complexes des deux types, monométalliques et bimétalliques, sont obtenus alors que pour le plomb, deux espèces monométalliques sont formées dans lesquelles le cation est soit du même côté, soit du côté opposé à l'anse, mais dans des proportions différentes. Enfin, le cation Bi(III) induit une seconde sphère de coordination inédite, responsable de l'insertion stéréosélective du métal. Qui plus est, un processus de transmétallation augmente la cinétique d'insertion du bismuth. Également, la présence d'un groupement cyano en position alpha de l'acide carboxylique génère une gêne stérique en coordination dans le cas du plomb, l'obligeant à coordiner la porphyrine sur sa face nue. / This thesis work concerns the synthesis of 5,10 single and bis-strapped porphyrin ligands (6, 11, 8i and 14i) bearing an overhung carboxylic acid group with/without an additional functional group (cyano and pyridine). The 5,10 meso linkage promotes a flexibility of the strap which allows the carboxylic acid group to be in two identified positions (in/out). The synthesis and characterization of the compounds are discussed in details, and the coordination of the ligands (6, 11, and 8i) with metals Zn(II), Hg(II), Pb(II) and Bi(III) have been investigated. In the case of Zn(II), five-coordinated metal in a square pyramidal geometry, the metal was stabilized by either an intramolecular carboxylic acid group or an exogenous molecule (DMSO or H2O). In the case of Hg(II), both monometallic and bimetallic species were obtained where for lead, two monometallic species were formed in which Pb(II) is coordinated from the same / opposite side of the strap with different ratios. Finally, Bi(III) promotes a new second sphere of coordination which is responsible for the side selective insertion of the metal. Beside, a transmetalation process speeds up the kinetic insertion of bismuth. In addition, the presence of a cyano group in the α position of the carboxylic acid group creates a steric effect on coordination (in case of Pb(II)) which forces the metal to coordinate from the opposite side of the strap.

La chimie des métaux alcalino-terreux lourds (calcium, strontium et baryum) a longtemps été décrite comme difficile et imprévisible contrairement à la chimie du magnésium, leur plus léger congénère. Cependant, au cours des dernières décennies, de nombreux complexes basés sur ce type de métaux ont émergés en tant que précatalyseurs efficaces pour un grand nombre de transformations organiques (polymérisation, hydroélémentation, couplage déshydrogénants, etc..). Cette thèse décrit la synthèse et l’étude (expérimentale et théorique) de nouveaux complexes de baryum de basse coordinance basée sur l’utilisation de ligands alcoolates pauvres en électrons. L’étude de ces composés a permis d’améliorer notre compréhension des différents phénomènes nécessaires à la stabilisation de tels composés. Dans un second temps, deux nouveaux systèmes de couplages déshydrogénants BO‒H/H‒Si et SiO‒H/H‒Si ont été développés et étudiés. Ces systèmes ont permis la formation catalytique de borasiloxanes et de siloxanes dissymétriques de façon sélective. Enfin, ces travaux montrent la synthèse et l’utilisation de nouveaux ligands ancillaires pour la formation de complexes hétéroleptiques de baryum stables. Ces derniers ont démontré une forte activité catalytique en hydrophosphination intermoléculaire avec des TOF pouvant atteindre 200 h-1 pour l’hydrophosphination du styrène par la HPPh2. / Heavy alkaline earth metals chemistry (calcium, strontium and barium) has been described as difficult and unpredictable for a long time, unlike the chemistry of magnesium, their lightest congener. However, in the last decades, many complexes based heavy alkaline earth metals have emerged as effective precatalysts for many applications and organic transformations (polymerization, hydroelementation, dehydrogenating coupling, etc.). This thesis describes the synthesis and study (experimental and theoretical) of new low-coordinate barium complexes based on electron-poor alkoxide ligands. The study of these compounds has improved our understanding of the different phenomena required to stabilize such compounds. Then, two new dehydrocoupling systems BO-H/H-Si and SiO-H/H-Si were developed and studied. These systems have allowed the catalytic formation of borasiloxanes and asymmetric siloxanes in a selective manner. Finally, this work shows the synthesis and use of new ancillary ligands for the formation of stable heteroleptic barium complexes. The latter have demonstrated strong catalytic activity in hydrophosphination with TOFs up to 200 h-1 for the intermolecular hydrophosphination of styrene by HPPh2.

No description available.