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Le 1,4,7-triazacyclononane (tacn) fait partie de la famille des polyazamacrocycles et a la faculté, lorsqu’il est N-fonctionnalisé par des groupements coordinants adéquats, de former des complexes de coordination stables thermodynamiquement et inertes cinétiquement avec les métaux de transition. C’est pourquoi les dérivés du tacn trouvent de nombreuses applications dans de nombreux domaines, par exemple celui de l’imagerie médicale. Notre équipe a développé des ligands N-fonctionnalisés par des groupements picolinate et méthylpyridine pour des applications en imagerie TEP et IRM.Le premier travail de cette thèse porte sur l’élaboration de nouvelles sondes bimodales TEP-imagerie optique et IRM-imagerie optique à motifs issus de tacn-picolinate décrits au laboratoire.Une seconde partie est axée sur la synthèse de nouveaux chélates du Cu(II) à base de tacn portant des bras méthylthiazole pour une potentielle application en imagerie TEP. Les complexes de Cu(II) correspondant ont été étudiés par différentes méthodes analytiques et spectroscopiques afin de juger leurs stabilités thermodynamiques et leurs inerties cinétiques.Les chélatants répondant aux critères imposés par le milieu biologique ont été sélectionnés pour une application en imagerie TEP dans le cadre du cancer de la prostate. Des analogues bifonctionnels ont ainsi été élaborés afin de les incorporer dans des radiopharmaceutiques radiomarqués au cuivre-64. / The 1,4,7-triazacyclononane (tacn) is part of the family of polyazamacrocycles, and has the faculty, when appropriately N-functionalized with coordination pendants, to form thermodynamically stable and kinetically inert coordination complexes with transition metals. Thanks to their properties tacn derivatives can be found in numerous applications such as medical imaging. Our group has developed some ligands N-functionalized with picolinate and picolyl pendants for an application in PET imaging and MRI.The first part of this thesis is focused on the development of a new class of bimodal PET-optical imaging and MRI-optical imaging probes based on tacn-picolinate units described in the laboratory.The second part deals with the synthesis of new Cu(II) chelators based on tacn-methylthiazolyl units for a potential application in PET imaging. The corresponding Cu(II) complexes were studied by different analytical and spectroscopic methods in order to evaluate their thermodynamic stabilities and kinetic inertness.The chelators that fullfiled all the criterias imposed by the biological media were selected for an applicationPET imaging of prostate cancer. Some bifunctional analogues were elaborated so as to incorporate them in radiopharmaceuticals radiolabeled with copper-64.

Le magnétisme est une propriété physique et intrinsèque de la matière, les matériaux paramagnétiques peut être utilisé pour la recherche chimique et biologique. Le changement du magnétisme d'une molécule qui peut être détectée par RMN ou ESR IRM représente un changement des conditions environnementales causées par certains analytes. Ainsi, elle est une alternative de méthodes typiques basées sur les propriétés optiques et elle attire les grands intérêts pour la recherche. La première partie introduit le magnétisme de la matière et l'IRM comme un outil indispensable dans le diagnostic modernes grâce à leur information claire et précise et les avantages de toxicité faible et de haute résolution spatiale. Le principe d'IRM et les facteurs influençant le temps de relaxation des protons de l'eau ont également été expliquées, suivie par l'élaboration de stratégies pour concevoir des sondes IRM puis la présentation des avantages de fer (II) et TACN qui a conduit à l'introduction de l'oeuvre précédente dans notre groupe. Ensuite, les avantages de la faible osmolarité et le dédouanement rapide de CAs électroneutre d'IRM rapporté dans les littératures ont été présentés alors le projet de doctorat a été proposé. La deuxième partie introduit deux stratégies pour atteindre l'électroneutralité selon les valeurs de pKa de l'acide pyridylcarboxylique et pyrimidinedione, qui a été suivie par le design, la synthèse et les études sur les propriétés basique de complexes cibles. Le TACN macrocyclique a été synthétisé à grande échelle qui nécessite beaucoup des compétences expérimentales, puis l'TACN monoalkylé a été préparé en une excellente pureté grâce aux méthodes explorées pour former leurs chlorhydrates. Quatre groupes (COOBn, COOEt, CONH2, CON(Me)(OMe)) pour fournir l'acide carboxylique sur le cycle pyridine et trois voies (deux alkylations et une amination réductrice) pour sa combinaison avec TACN sont essayés. Les ligands portant les groupes ester d'éthyle sont obtenus qui ont été ensuite hydrolysé dans des conditions acides pour la complexation avec le fer (II), et les complexes obtenus ont été caractérisées par HRMS et celui-ci avec bas spin a ses 1H RMN et diffraction des rayons X. Tous deux ont été utilisé pour la mesure de leurs propriétés telles que relaxivités, moment magnétique, UV-vis absorptions, pH titration, la cytotoxicité, et voltammogramme cyclique. Les résultats ont montré qu'ils ont leurs propres relaxivités raisonnables, relativement faible cytotoxicité et une grande stabilité dans les milieux physiologiques, ce qui implique leur application potentielle dans le design de sondes d'IRM. Les complexes de type N6 et N5O1 portant quatre groupes méthoxyles basés sur la pyrimidine sont synthétisés et celui de type N6 a montré l'état de haut spin selon son analyse DRX. La déprotection du ligand N6 a réussi après de nombreuses méthodes essayées, mais la condition doit être contrôlée strictement et sa complexation est suggéré dans la présence d'un base pour améliorer la solubilité du ligand dans du MeOH, EtOH et de l'acétonitrile. La troisième partie est la section expérimentale qui décrit toutes les conditions et les résultats des réactions réussies, et la synthèse des intermédiaires de certaines stratégies efficaces. En conclusion, deux complexes électroneutres, ferreux et binaires à base d'acide pyridylcarboxylique ont été synthétisés et caractérisés. A notre connaissance, c'est le premier exemple d'un complexe ferreux avec bas spin en version eletroneutre. Leurs propriétés ouvrent une voie prometteuse pour le design de sondes d'IRM basés sur eux. Le totalement nouveaux N6 complex protégé par quatre méthyle basé sur pyrimidinedione a été synthétisé et il est intéressant d'étudier le magnétisme de sa forme déprotégée par rapport à sa propriété haut-spin. À l'heure actuelle une meilleure méthode de déprotection et de complexation est à l'étude. / Magnetism is an intrinsic physical property of matter, the paramagnetic materials can be used for chemical and biological research. The magnetism change of a molecule which can be detected by NMR, MRI or ESR stands for a change of environmental conditions caused by some analytes. Thus it is an alternative readout besides the typical methods based on optical properties and it attracts our great interest for research. The first part introduced the magnetism of matter and MRI as an indispensable tool in modern diagnostics due to their accurate and specific information and moreover the advantages of low toxicity and high spatial resolution. The MRI principle and the influencing factors of relaxation time of water protons were also explained, followed by the elaboration of strategies to design MRI probes then the presentation of advantages of iron(II) and TACN which led to the introduction of the previous work in our group. Afterwards the advantages of the low osmolarity and fast clearance of electroneutral MRI CAs reported in the literatures were presented then the PhD project was proposed. The second part introduced two strategies to achieve electroneutrality according to pKa values of pyridylcarboxylic acid and pyrimidinediol, which was followed by design, synthesis and studies on basic properties of the target complexes. The macrocycle TACN was synthesized in large scale which requires much experimental skills, then the monoalkylated TACN was prepared in excellent purity due to the explored methods to form their hydrochlorides. Four groups (COOBn, COOEt, CONH2, CON(Me)(OMe)) for providing carboxyl group on the pyridine ring and three ways (two alkylations and one reductive amination) for its combination with TACN were tried. The ligands bearing the ethyl ester groups were successfully obtained, which were subsequently hydrolyzed under acidic condition for complexation with iron(II) salt, and the obtained complexes were characterized by HRMS and the low-spin one has its 1H NMR and X-Ray Diffraction. Then both of two complexes were used for measurements of their properties such as relaxivities, magnetic moment, UV-vis absorptions, pH titration, cytotoxicity, and cyclic voltammogram. The results showed that they have their own reasonable relaxivities, relatively low cytotoxicity and high stability in physiological media, which implies their potential application in design of MRI probes. The N6 and N5O1 type complexes bearing four methoxyl groups based on pyrimidine were also successfully synthesized and the former showed high-spin state by its XRD analysis. The deprotection of the N6 ligand was successful after many methods were tried, but the condition should be controlled strictly and its complexation in the presence of some base is suggested for improving the solubility of the ligand in MeOH, EtOH and acetonitrile. The third part is the experimental section which described all the conditions and results of the successful reactions, and synthesis of the intermediates of some unsuccessful strategies. In conclusion, the high-spin and low-spin, electroneutral, ferrous and binary complexes based on pyridylcarboxylic acid have been synthesized and characterized. To our knowledge, this is the first instance of an eletroneutral version of a low-spin ferrous complex. Their properties pave a promising way for designing MRI probes based on them. The totally novel N6 type complex bearing four methyl groups based on pyrimidinediol has been synthesized and it is worth studying magnetism of the deprotected form compared to its high-spin property. At present a better method of deprotection and complexation is being explored.

Les polyazamacrocycles trouvent de nombreuses applications dans le domaine de la complexation de cations métalliques ou d'anions. Le laboratoire à longtemps étudié la fonctionnalisation des dérivés tétraazamacrocycliques et leurs propriétés de complexation. Afin d'accroître le savoir-faire du laboratoire et d'explorer de nouvelles propriétés de complexation des polyamines cycliques, nous nous sommes intéressé à transposer ce savoir à la fonctionnalisation d'un macrocycle plus petit : le tacn. Ce travail repose sur la mise au point d'une nouvelle stratégie de fonctionnalisation sélective du tacn et la synthèse de nouveaux dérivés. Les composés obtenus ont permis l'étude de leurs propriétés de complexation vis-à-vis de différents métaux de transition. Les propriétés de complexes de cuivre (II) ont été étudiées pour des applications en imagerie TEP ou en radioimmunothérapie. La détection de zinc (II) basée sur une détection IRM par de nouvelles sondes ditopiques tacn-do3a a été étudiée. La complexation de fer (II) pour des applications en transition de spin ont également permis de déterminer les propriétés de complexation de dérivés du tacn. / The polyazamacrocycles have many applications in the field metal cations or anions complexation. Our laboratory studied the functionalization of tetraazamacrocyclic derivatives and their complexation properties during a long time. To enhance the expertise of our laboratory and to explore new properties of complexation of cyclic polyamines, we were interested in transpose his expertise to the functionalization of a smaller macrocycle: the tacn. This work is based on the development of a new synthetic strategy of selective functionalization of tacn and the synthesis of new derivatives. The complexation properties of this new functionalized macrocycles with different transition metals were also studied. The properties of copper (II) complexes have been studied for applications in Positron Emission Tomography (PET) imaging or radioimmunotherapy (RIT). The detection of zinc (II) based on Magnetic Resonance Imaging (MRI) detection by new ditopic probes tacn-do3a has been studied. Complexation of iron (II) for applications in spin crossover also revealed the complexation properties of the tacn derivatives.

Les polyazamacrocycles trouvent de nombreuses applications dans le domaine de la complexation de cations métalliques ou d'anions. Le laboratoire à longtemps étudié la fonctionnalisation des dérivés tétraazamacrocycliques et leurs propriétés de complexation. Afin d'accroître le savoir-faire du laboratoire et d'explorer de nouvelles propriétés de complexation des polyamines cycliques, nous nous sommes intéressé à transposer ce savoir à la fonctionnalisation d'un macrocycle plus petit : le tacn. Ce travail repose sur la mise au point d'une nouvelle stratégie de fonctionnalisation sélective du tacn et la synthèse de nouveaux dérivés. Les composés obtenus ont permis l'étude de leurs propriétés de complexation vis-à-vis de différents métaux de transition. Les propriétés de complexes de cuivre (II) ont été étudiées pour des applications en imagerie TEP ou en radioimmunothérapie. La détection de zinc (II) basée sur une détection IRM par de nouvelles sondes ditopiques tacn-do3a a été étudiée. La complexation de fer (II) pour des applications en transition de spin ont également permis de déterminer les propriétés de complexation de dérivés du tacn.

It has been observed that in certain cases the exposure of dyed fibres to aging techniques results in the strengthening of fibres. This thesis explores the hypothesis that the strengthening is due to radical cross-coupling reactions that could be initiated through metal ion mediated photodecarboxylation. The approaches taken in this research include kinetic experiments (using flash photolysis), examination of possible cross-coupling experiments (using species of opposite charge), and the design and examination of small molecule model systems. A flash photolysis system was developed and used in attempts to determine the rates of photochemical product formation for cobalt(III) amino acid complexes. Lower limits have been established for the rate of product formation in these systems. The lower limits are: 2 x 10⁷ s⁻¹ for [Co(bpy)2(gly)]²⁺; 2 x 10⁷ s⁻¹ for [Co(tpa)(gly)]²⁺; and 5 x 10⁶ s⁻¹ for [Co(tpa)(aib)]²⁺, where bpy is 2,2'-bipyridine; gly is glycinate; tpa is tris(2-pyridylmethyl)amine; and aib is aminoisobutyrate. In past studies, the rates of a series of cobalt(III) amino acid complexes were reported as being the same, and much slower. It is thought that in these cases it may not be the rate of the formation of product that was being measured, but rather the response time of the electronics that was being observed. In this thesis the results obtained for the rate for the aib complex were somewhat lower than those of the gly complexes. This may imply, for the aib complex at least, the rate of the formation of the metallocycle is being observed (and not the response times of the electronics or other limitations of the instrumentation), but the data is poor and there is considerable doubt about this. The steady state photolysis of opposite charged species [Co(bpy)2(gly)]²⁺ and [Co(EDTA)]⁻ is reported. The reactions were carried out on a small scale in deuterated solvent for NMR spectrometry analysis and also on a large scale for the possible isolation and characterisation of the products. Evidence was found for a different reaction occurring when both complexes were present. The exact nature of the product remains elusive. A model system was designed in which a dinuclear ligand would bind to two metal centres and a fibre mimic would be later added. Eight ligands are discussed that could potentially bind two octahedral metal centres. They all had a xylene spacing group linking the two polydentate sites together. Five of the ligands have two bidentate binding sites. The other three had two tridentate sites. The binding sites in three of the bis(bidentate) ligands were based on ethane-1,2- diamine (en). Two of these ligands produced hypodentate monocobalt and sundentate dicobalt complexes. The other two bidentate ligands were based on 2- aminomethylpyridine (ampy). Both of these ligands degraded in the complexation reaction conditions. The binding sites in the tridentate ligands were all based on tacn. Once again, the principal products isolated were hypodentate systems in which only one metal ion was coordinated by the ligands. There is a distinct pattern observed in the xylene spaced ligands to form hypodentate complexes with cobalt(III) metal centred complexes. There is evidence of the di-nuclear species from a reaction with a charcoal catalyst in the bis(bidentate) system. ¹H NMR spectrometry, ¹³C NMR spectrometry, elemental analysis, X-ray crystallography and UV-vis spectroscopy were used to study and characterise the complexes and ligands that were prepared in this project.

It has been observed that in certain cases the exposure of dyed fibres to aging techniques results in the strengthening of fibres. This thesis explores the hypothesis that the strengthening is due to radical cross-coupling reactions that could be initiated through metal ion mediated photodecarboxylation. The approaches taken in this research include kinetic experiments (using flash photolysis), examination of possible cross-coupling experiments (using species of opposite charge), and the design and examination of small molecule model systems. A flash photolysis system was developed and used in attempts to determine the rates of photochemical product formation for cobalt(III) amino acid complexes. Lower limits have been established for the rate of product formation in these systems. The lower limits are: 2 x 10⁷ s⁻¹ for [Co(bpy)2(gly)]²⁺; 2 x 10⁷ s⁻¹ for [Co(tpa)(gly)]²⁺; and 5 x 10⁶ s⁻¹ for [Co(tpa)(aib)]²⁺, where bpy is 2,2'-bipyridine; gly is glycinate; tpa is tris(2-pyridylmethyl)amine; and aib is aminoisobutyrate. In past studies, the rates of a series of cobalt(III) amino acid complexes were reported as being the same, and much slower. It is thought that in these cases it may not be the rate of the formation of product that was being measured, but rather the response time of the electronics that was being observed. In this thesis the results obtained for the rate for the aib complex were somewhat lower than those of the gly complexes. This may imply, for the aib complex at least, the rate of the formation of the metallocycle is being observed (and not the response times of the electronics or other limitations of the instrumentation), but the data is poor and there is considerable doubt about this. The steady state photolysis of opposite charged species [Co(bpy)2(gly)]²⁺ and [Co(EDTA)]⁻ is reported. The reactions were carried out on a small scale in deuterated solvent for NMR spectrometry analysis and also on a large scale for the possible isolation and characterisation of the products. Evidence was found for a different reaction occurring when both complexes were present. The exact nature of the product remains elusive. A model system was designed in which a dinuclear ligand would bind to two metal centres and a fibre mimic would be later added. Eight ligands are discussed that could potentially bind two octahedral metal centres. They all had a xylene spacing group linking the two polydentate sites together. Five of the ligands have two bidentate binding sites. The other three had two tridentate sites. The binding sites in three of the bis(bidentate) ligands were based on ethane-1,2- diamine (en). Two of these ligands produced hypodentate monocobalt and sundentate dicobalt complexes. The other two bidentate ligands were based on 2- aminomethylpyridine (ampy). Both of these ligands degraded in the complexation reaction conditions. The binding sites in the tridentate ligands were all based on tacn. Once again, the principal products isolated were hypodentate systems in which only one metal ion was coordinated by the ligands. There is a distinct pattern observed in the xylene spaced ligands to form hypodentate complexes with cobalt(III) metal centred complexes. There is evidence of the di-nuclear species from a reaction with a charcoal catalyst in the bis(bidentate) system. ¹H NMR spectrometry, ¹³C NMR spectrometry, elemental analysis, X-ray crystallography and UV-vis spectroscopy were used to study and characterise the complexes and ligands that were prepared in this project.