Multifunctional molecular materials based on donor-acceptor systems
- Autores: Judit Guasch Camell
- Directores de la Tesis: Imma Ratera Bastardas (dir. tes.), Jaume Veciana i Miró (dir. tes.)
- Lectura: En la Universitat Autònoma de Barcelona ( España ) en 2011
- Idioma: español
- Tribunal Calificador de la Tesis: Silvio Decurtins (presid.), Adelina Vallribera Massó (secret.), Juan T. López Navarrete (voc.)
- Materias:
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- Resumen
In the framework of this thesis, we synthesized and studied different families of multifunctional molecular materials based on donor-acceptor (DA) systems with interesting magnetic, electrical, optical, and biological properties in solution, in bulk, and on surfaces.
In the first part of this work, we demonstrated the bistability phenomenon in solid state of a family of dyads formed by the polychlorotriphenylmethyl radical (acceptor) linked to ferrocene derivatives (donor) through a vinylene bridge. In order to rationalize the coexistence of both the neutral and the zwitterionic states, i.e. the bistability of these dyads, we developed a theoretical bottom-up approach. This model confirmed the important role of the electrostatic intermolecular interactions in addition to the intramolecular electron transfer (IET) process on the bistability phenomenon exhibited by these dyads in a range of temperatures that includes r.t. Furthermore, we demonstrated the possibility of tuning the IET and the electrostatic intermolecular interactions by changing the donor strength of the dyads using common synthetic procedures. In addition, we observed the presence of pseudobistability in some dyads, i.e. the presence of both states in solution, the neutral and the zwitterionic, when solvents with an intermediate polarity such as acetone were used.
In the second part of this thesis work, we synthesized and characterized a new family of compounds based on the polychlorotriphenylmethyl radical (acceptor) linked to the tetrathiafulvalene (donor) through a vinylene bridge in order to produce new bistable systems. The pseudobistability phenomenon was also observed in solution when solvents with a high polarity were used. In this case, the coexistence of the two states of the dyads was possible thanks to the aggregation processes exhibited by their TTF subunit. In order to study in detail these aggregation phenomena, we analyzed the two types of dimerization processes known for the TTF derivatives, the pi-dimerization and the mixed valence dimerization processes.
Then, we went one step further towards the applications of this last family of dyads depositing them on surfaces. We characterized different nanostructures and we were able to obtain asymmetric rectification curves for one, confirming the rectification capacity of this dyad on a surface by conductive AFM measurements.
In the last part of this thesis, we worked with a family of cytotoxic 2-amino-naphtho[2,3-b]furan-4,9-dione dyads. We characterized the electronic properties of this family of dyads in solution by means of their redox properties and the solvatochromism exhibited by their IET bands and we suggested a relationship between them and their cytotoxicity.
