La complexation de l'arénophile à un ligand naphtalène substitué sur un seul noyau par un ou deux groupe triméthylsilyléthynyle conduit à la formation des deux régio-isomères A (arénophile coordiné au cycle substitué) et B (arénophile lié au cycle libre). L'isomère A est le produit cinétique et l'isomère B le produit thermodynamique de la réaction. La substitution du groupe trimétylsilyle par le fragment organométallique électro-actif permet d'étudier l'isomérisation A B . La migration haptotropique électro-induite, réalisée à 20 °C, est quasi quantitative . Elle résulte de l'activation de la liaison Ru provoquée par l'oxydation mono-électronique du centre redox organofer en présence d'un solvant coordinant . La synthèse du complexe ortho disubstitué, stériquement très encombré, et de ses dérivés mono- et di-oxydés a été effectuée avec succès. L'espèce mono-oxydée qui possède un couplage électronique fort est un dérivé à valence mixte de classe II B, à la limite entre les classes II et III. Les complexes tétranucléaires ont également été synthétisés et caractérisés par différentes techniques incluant notamment la radiocristallographie. Ces composés présentent des interactions électroniques à la fois en ortho, meta et para, générant de nouvelles propriétés qui pourraient s'avérer totalement inédites dans le domaine de l'électronique moléculaire. Finalement, une nouvelle famille de composés hybrides organiques inorganiques trans- a aussi été préparée (TTF = tétrathiafulvalène; n = 0-3). Le dérivé mono-oxydé est un composé à valence mixte de classe II. Le transfert d'électron intramoléculaire peut se faire selon un mécanisme par effet tunnel et par un mécanisme multi-étape par sauts entre les centres redox inorganiques et organiques. / The complexation of the arenophile to a naphthalene ligand bearing one or two trimethylsilylethynyle group gives the two regioisomers A (arenophile coordinated to the substituted ring) and B (arenophile coordinated to the free cycle). Isomer A is the kinetic product and isomer B is the thermodynamic product of the reaction. The substitution of the trimethylsilyl group by the electroactive organometallic fragment allows to control the isomerization from A to B. The electro induced haptotropic migration, performed at 20 ° C, is almost quantitative, and results from the activation of the Ru bond induced by the one-electron oxidation of the organoiron redox center in the presence of a coordinating solvent. The synthesis of the sterically constraint ortho disubstituted complex, and its mono and di-oxidized forms were successfully achieved. The mono-oxidized species that shows a strong electronic coupling is a Class-II B mixed valence compound. The tetranuclear complexes were also prepared and characterized by various methods including X-ray crystallography. These compounds exhibit electronic interactions in the ortho, meta and para positions, generating new properties that could be of great interest in the field of molecular electronics. Finally, a new family of organic-inorganic hybrids trans- has also been prepared (TTF = tetrathiafulvalene; n = 0-3). The mono-oxidized complex (n = 1) is a Class-II mixed-valence compound in which the spin density varies with the respective orientation of the metal termini. Intramolecular electron transfer occurs through single-step tunneling and multiple-step hopping mechanisms.

Les travaux de la présente thèse porteront sur le raffinement du modèle du potentiel source-puits (SSP) proposé par Ernzerhof en 2006. Cette méthode permet de calculer la conductance qualitative de dispositifs électroniques moléculaires (MEDs). Dans la première partie de ce travail, le modèle SSP sera amélioré en y intégrant la description de l’interaction d’un champ électromagnétique fort avec le MED. Des expériences récentes ont démontré que des molécules pouvaient interagir fortement avec des plasmons de polaritons de surface (SPP). Ces interactions créent des états liés électron-SPP qui seront exploités pour contrôler la conductance de MEDs. Des formules analytiques expliqueront l’impact des paramètres physiques de ces circuits optoélectroniques sur la conductance de ceux-ci. Dans le même esprit, la seconde partie de cette thèse inclura les interactions électron-noyau au modèle SSP afin de décrire entre autres le courant décohérent d’un MED. Dans ce modèle les interactions noyau-électron seront décrites à partir de l’approximation harmonique et intégrées à l’hamiltonien de façon non-pertubative. Des formules analytiques seront dérivées afin de décrire la conductance de tels MEDs. Finalement, les conséquences du bris de la symétrie de la parité et du temps de la matrice hamiltonienne de la méthode SSP seront découvertes dans la densité spectrale et les fonctions d’ondes des MEDs. / The purpose of this thesis is to expand the scope of the source-sink potential (SSP) method originally proposed by Ernzerhof in 2006. The SSP model allows the computation of the qualitative conductance of molecular electronics devices (MEDs). In the first part of this work, the SSP model will be improved by including the description of interaction between the strong electromagnetic field and the MED. Recent experiments have shown that molecules could strongly interact with surface plasmon of polaritons (SPPs). These interactions will create so-called dressed states that can be used to control the conductance of MEDs. In the second part of this work, the SSP model will be augmented by including electron-nucleus interactions to describe the inelastic current. In this model, the electron-nuclueus interaction will be account for with the help of the harmonic approximation and incorporated into the hamiltonian non-pertubatively. Analytical formulas will be derived that will allow one to understand the impact of physical parameters on the conductance of MEDs. Lastly, the impact of the parity and time symmetry breaking of the SSP matrix hamiltonian will be studied and related to change in the spectral density and in the eigenfunctions of the MEDs.

The subject of this thesis is to study the interaction between carbon nanotubes (CNTs) and antiferromagnetic tetrametallic molecules attached to them. By employing quantum transport measurements, the sensitivity to sense the interactions is greatly increased, because the quantum dot is very susceptible to changes in its environment. The properties of carbon nanotubes can be altered by chemical functionalization with the aforementioned molecules, where the attachment is performed covalently via a ligand exchange with the CNT. The thesis is partitioned into two main parts: the first part presents experiments performed on tetramanganese functionalized CNTs, whereas for the second similar studies are conducted, except manganese is replaced by cobalt. Both complexes exhibit an antiferromagnetic ground state, yet the metal spin of manganese (S=5/2) is reduced to S=3/2 for cobalt. Additionally, an altered device preparation has been employed during the second part, leading to a strong suppression of the background signal. Quantum transport measurements at T=4K on manganese-functionalized CNTs show a very regular pattern of Coulomb diamonds, indicating only a mild disturbance of the quantum dot's electron system by the covalent bond. Moreover, the charging energy reveals a wave function extending over the entire device dimensions. However, at T=30mK in the tunneling current a strong noise emerges, when repeatedly measuring over an hour while keeping external biases constant. Additionally, these time traces are superimposed by a long-term background, which is removed by a correction algorithm plus a subsequent digitization. The remaining signal reveals a random telegraph signal (RTS) which is extensively studied and from its statistics the equivalent temperature of T=654mK for the excitation of the system is extracted. The quantum transport experiments conducted on cobalt-functionalized CNTs show a much better data quality of the coulomb diamonds, which is ascribed to the alteration in the device's preparation. From the line shape of the Coulomb oscillations as well as from the Coulomb staircases an electron temperature of about T=500mK is extracted. Moreover, a magnetic field dependence of the stability diagrams is apparent, attributable to Zeeman splitting. The respective Landé factor of g=1.73 is, compared to similar CNT quantum dot systems, unusually low. It is as attributed to an increased spin-orbit interaction between the conduction electrons and the cobalt's nuclei. The respective time traces exhibit or lack an RTS signal, depending on their external biases. Regarding the Coulomb diamonds, an essential prerequisite for the occurrence of an RTS is the proximity to a resonance, which is equatable to a high sensitivity of the quantum dot detector. Considering the available energy, the underlying process that is the cause for the emergence of the RTS is ascertained to be an internal excitation of the antiferromagnetic states of the metallic core.