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.

Le travail présenté dans ce manuscrit concerne la conception et les études magnéto-structurales de nouveaux systèmes de Fe(II) à transition de spin (TS), en particulier ceux faisant intervenir les tétraazamacrocycles fonctionnalisés et les ligands de type 4-R-1,2,4-triazole. L’objectif principal est l’étude de l’effet de substitution ou de solvants (ou mélange de solvants) sur le comportement élastique de ces matériaux originaux. Dans un premier temps, nous avons étudié l’effet de solvant et contre-ions sur les propriétés de commutation, dans une série des complexes [Fe(L2)](X).nH2O (L2 = 1,8-bis(2’-pyridylméthyl)-1,4,8,11-tétraaza-cyclotétradécane, X = 2(tcm)- = 2[C(CN)3]-, n = 2 (1) ; X = [Ni(CN)4]2-, n = 1 (2) ; X = (BF4)-, n = 1 (3)). Cette étude a clairement élucidé l’effet crucial des interactions hydrogène, à travers les contre-ions et les molécules de solvants, sur la coopérativité observée dans la série des trois sels. Dans un second temps, l’utilisation des ligands de type 4-R-1,2,4-triazole nous a permis l’étude de deux systèmes commutables : (i) le premier concerne un complexe trinucléaire de formule [Fe3(furmetrz)6(tcnsme)6] (furmetrz = 4-(furan-2-ylmethyl)-1,2,4-triazole ; (tcnsme)- = 1,1,3,3-tétracyano-2- thiométhylpropenure), pour lequel les études magnétiques ont mis en évidence une transition thermique en deux étapes et un effet LIESST avec une T(LIESST) de 58 K. La comparaison de ce dérivé à d’autres systèmes similaires, mais présentant une transition de spin en une seule étape, révèle que la présence de deux étapes est favorisée par de fortes interactions le long de l’axe du trimère ; (ii) le second système concerne l’étude de plusieurs séries de matériaux polyfonctionnels exhibant la transition de spin et la photoluminescence. Le résultat le plus marquant concerne la synthèse et l’étude du complexe mononucléaire [Fe(naphtrz)6](tcnsme)2.4CH3CN (naphtrz = N-(1,2,4-triazol-4-yl)-1,8-naphthalimide) pour lequel les études magnétiques et optiques ont montré l’existence des deux propriétés, d’une manière synergétique. Ce résultat prouve la possibilité de contrôler, sans ambiguïté, les propriétés optiques par des excitations extérieures telles que la température, la pression, la lumière, … Au-delà de l’aspect fondamental, ce travail ouvre aussi des perspectives très originales pour l’utilisation de ces matériaux comme capteurs ou étalons de température. / This work is dedicated to the design and magnetostructural studies of new Fe(II) spin crossover (SCO) systems, in particular those involving the functionalized macrocycle and the 4-R-1,2,4-triazole triazole ligands.The principal objective concerns the study of the substitution and solvent effects on the SCO characteristics. In the first step, we have studied the solvent and the counter-ion effects, on the SCO behavior, in the series [Fe(L2)](X).nH2O (L2 = 1,8-bis(2’-pyridylméthyl)-1,4,8,11-tétraaza-cyclotétradécane, X = 2(tcm)- = 2[C(CN)3]-, n = 2 (1) ; X = [Ni(CN)4]2-, n = 1 (2) ; X = (BF4)-, n = 1 (3)), based on the macrocycles ligands. We have clearly shown in this study that the strong cooperative effects are mediated by the water solvent molecules and the counter-ions involved in the hydrogen bonding in the crystal packing. In the second step, the use of the 4-R-1,2,4-triazole fuctionalized triazole ligands led us to two original switchable systems: (i) the first one concerns the trinnuclear complex of formulae Fe3(furmetrz)6(tcnsme)6] (furmetrz = 4-(furan-2-ylmethyl)-1,2,4-triazole; (tcnsme)- = 1,1,3,3-tetracyano-2- thiométhylpropenide), for which the magnetic study reveals a two-step SCO transition and a LIESST effects with a T(LIESST) of 58 K. Examination of the intermolecular interactions in this complex and other parent trinuclear systems exhibiting complete one-step spin transition, revealed that the presence of the two-step behavior is clearly favored by strong inter-trimer interactions along the trimer axis; (ii) the second system the design and syntheses of to several series of polyfunctional materials exhibiting SCO and luminescent behaviors. In this new way, the most significant result concerns an original discrete Fe(II) complex of formulae [Fe(naphtrz)6](tcnsme)2.4CH3CN (naphtrz = N-(1,2,4-triazol-4-yl)-1,8-naphthalimide), for which the magnetic and photoluminescent studies showed that this material exhibits synergetic SCO and luminescent behaviors. This proves the possibility to control the luminescent properties through simple external perturbations such as temperature, pressure, light irradiation,… In addition, beyond the fundamental aspect, this work open new innovative perspectives for the use of such original materials as sensors or standards of temperature.

The nucleus is a mesoscopic system that retains features from both the quantum and macroscopic worlds. A basic property of a macroscopic body is its shape. Nuclear shapes can be deduced from experimental data as they influence the excitation mode of the nucleus and hence the energies and lifetimes of its excited levels. Various short-lived nuclei were created in fusion-evaporation experiments performed at international heavy-ion accelerator facilities. The emitted γ rays and, in some experiments, also the charged particles and neutrons emitted in the reactions were detected. The studied neutron-deficient isotopes were either selected by the type and number of particles emitted in the reactions, or by using their characteristic decays. The excited states of the different isotopes were extracted from the γ-ray analyses. Spectroscopic properties, such as the lifetimes of the excited states or the angular distribution of the emitted γ rays were measured when possible. The experimentally obtained level schemes together with the other spectroscopic information were used to deduce the excitation modes and the shapes of the studied nuclei. The detector systems are described in the first chapter and in the second chapter some techniques used to extract information from the experimental data are explained. Finally, a brief theoretical overview on the nuclear models which were used to interpret the experimental results is given. / QC 20100621

New high-K isomers have been populated in Ta and W by bombarding thick targets with pulsed 238U beams at 1600 MeV. The new inelastically excited multi-quasiparticle states include Kpi = 21/2- and 29/2- 3-quasiparticle isomers in 181Ta and Kpi = 7- and (16+) isomers in 186W. The Kpi = (16+) state in 186w has t1/2≥3 ms and extends the 4-quasiparticle isomer systematics beyond the limit accessible with fusion-evaporation reactions, using stable beams and targets, for the first time. In addition, a t1/2≥1 ms 3-quasiparticle isomeric state feeding a strongly coupled rotational band has been populated in Ta by nucleon transfer. The excitation energies of the intrinsic states are compared to predictions of blocked BCS calculations. A different study of high-K states used a radioactive 14C beam at 67 MeV to investigate the high-spin structure of Os. New rotational bands built on multi-quasiparticle states with Kpi = 5-, 7-, 9-, 10+ and 15+ are observed. The first crossing of the ground-state band at I = 14 h, is interpreted as involving a high-K t-band structure and explained using a two-band mixing model. The structure at higher angular momentum is dominated by intrinsic states, that exhibit a dramatic loss of isomerism. Potential-energy-surface calculations, with Lipkin-Nogami pairing, show these configurations to be triaxial, accounting for the breakdown in K conservation. The relation between the K projection and the total angular momentum is investigated for these non-axial states.

Philosophiae Doctor - PhD / In the first experiment high spin states in 194Tl, excited through the 181Ta (18O, 5n) heavyion fusion evaporation reaction were studied using the AFRODITE array at iThemba LABS. The γ-γ coincidences, RAD ratios and linear polarization measurements were carried out and the previously known level scheme of 194Tl was significantly extended. A total of five rotational bands four of which are new were observed. A pair of rotational bands associated with the πh9/2 ⊗ νi−1 13/2 configuration at lower spins and with the πh9/2 ⊗ νi−3 13/2 configuration at higher spins was found and interpreted as the first possible chiral bands followed above the band crossing. The two 4-quasiparticle bands show exceptionally close near-degeneracy in the excitation energies. Furthermore close similarity is also found in their alignments and B(M1)/B(E2) reduced transition probability ratios. In the second experiment lifetimes in 194Tl were measured using the DSAM technique with the excited states in this nucleus populated through the 181Ta (18O, 5n) reaction. A total of 25 lifetimes and 30 reduced transition probabilities of magnetic dipole B(M1) and electric quadrupole B(E2) have been evaluated. Furthermore B(M1) and B(E2) reduced transition probabilities in Bands 1 and 4, which have been regarded as chiral candidates, were found to be close to each other and reveals strong splitting along spin values. This further supports the proposed chiral nature of these two bands.

No description available.

Par une approche supramoléculaire, des architectures radiales hétéro-poly-métalliques ont été réalisées pour des applications en photosynthèse artificielle et en magnétisme moléculaire. Dans une première partie, la synthèse et la caractérisation (spectroscopie UV-vis, émission, électrochimique, DRX) de complexes de ruthénium(II), possédant une gamme de ligands polypyridines, ont été réalisées. Les calculs théoriques ont été effectués afin de soutenir l’interprétation des propriétés photophysiques. Ces complexes, présentant un certain nombre de pyridines externes, ont servi de cœur à des architectures à base de rhénium tris-carbonyles (pour les effets d’antenne), et de cobaloximes (pour les propriétés catalytiques). Les nucléarités obtenues varient de 2 à 7 selon le cœur utilisé. Ces systèmes ont été engagés dans des cycles de photo-production de dihydrogène, démontrant une meilleure efficacité que la référence du domaine, le [Ru(bpy)3]2+. La seconde partie concerne l’étude de couples de métaux de transition, construits à partir de briques polycyanométallates, ou de lanthanides pontés par des ligands oxamides. Ces approches « complexes comme ligand » puis « assemblages comme ligand » permettent d’obtenir des systèmes de haute nucléarité, présentant des propriétés de molécule-aimant ou des effets magnéto-caloriques (à base de CrNi, GdCu, DyCu). Des propriétés photomagnétiques ont été observées sur les couples RuCu et MoCu, pouvant servir de commutateurs moléculaires dans des systèmes complexes. Enfin, une structure hétéro-tétra-métallique trifonctionnelle a été obtenue contenant à la fois un commutateur MoCu, une entité molécule-aimant CuTb et un complexe de ruthénium. / By a supramolecular strategy, radial hetero-poly-metallic architectures were obtained for applications in artificial photosynthesis and molecular magnetism. The first part is devoted to the synthesis, as well as the photophysical characterization (UV-vis absorption, emission, electrochemistry, X-ray diffraction) of ruthenium(II) complexes bearing a wide range of polypyridine ligands. Theoretical calculations were performed to support the interpretation of the photophysical properties. Through their pendant pyridine moieties, these complexes were used as core of architectures, bearing rhenium tris-carbonyl (for antenna effects), and cobaloximes (for catalytic properties) complexes. The nuclearities obtained vary from two to seven according to the core involved. These systems were engaged in photo-production of hydrogen, demonstrating more efficient systems than the reference in the field, the archetypal [Ru(bpy)3]2+. The second part concerns the study of transition metal couples, built on polycyanometallate cores, or oxamide-bridged lanthanide-based assemblies. These “complex as ligand” and “assemblies as ligand” approaches allow us to obtain high nuclearity systems on which we seek single molecule magnet (SMM) properties or good magnetocaloric effect (based on CrNi, GdCu, DyCu). Photo-magnetic properties have been studied on the RuCu and MoCu couples, which can serve as molecular switches in complex systems. Finally, a tri-functional hetero-tetra-metallic architecture was obtained containing a MoCu switch, a CuTb SMM entity, and a ruthenium complex.

Os núcleos, ímpar-ímpar ANTPOT. 132,134 La foram estudados através de técnicas de espectroscopia em linha de reações tipo (HI, xn). Foram usados feixes de ANTPOT. 10,11 B(40-48 MeV) e ANTPOT. 14 N (55 MeV) em alvos de ANTPOT. 128,128 Te e ANTPOT. 122 Sn no acelerador Pelletron. Foi observada uma banda rotacional, presumidamente sobre a configuração h IND. 11/2 e h IND. 11/2 em cada um dos isótopos, mostrando valores de \"signature splitting\" moderados. No ANTPOT. 132 La uma outra banda foi observada essencialmente sem \"signature splitting\". Os resultados são comparados com as previsões do \"Cranking Shell Model\" triaxial. A relação entre triaxialidade e \"signature splitting\" na região de transição A ~ 130 é discutida. / The odd-odd nuclei 132,134La were studied by means of in-beam -ray spectroscopy techniques, using (HI, xn) reactions with 10,11B (40-48 MeV), 14N (55 MeV) beams on 128,128Te and 122 Sn targets. A band, probably based on the h11/2 and h11/2 configuration, was observed in each La isotope showing moderate signature splitting. Another band was observed in 132La with essentially no signature splitting. The results are compared with the triaxial Cranking Shell Model predictions. The relation between triaxiality and signature splitting in the A ~ 130 transitional mass region is discussed.

Thesis (Ph.D.); Submitted to North Carolina State Univ., Raleigh, NC (US); 6 Apr 2005. / Published through the Information Bridge: DOE Scientific and Technical Information. "UCRL-TH-211400" Dashdorj, D. 04/06/2005. Report is also available in paper and microfiche from NTIS.

Made available in DSpace on 2014-10-09T12:42:54Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:07:52Z (GMT). No. of bitstreams: 1 05403.pdf: 3608647 bytes, checksum: 066e3f6af2ef001c7431582e2ce35791 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP / FAPESP:96/01220-7