Design and synthesis of photoswitchable coordination complexes
[eng] One of the main objectives of this thesis was the synthesis of new chelating ligands containing a photochromic unit able to change its conformation upon light irradiation. This isomerization should serve to modify the magnetic behavior of the new coordination compounds, formed upon reaction of...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2016 |
| País: | España |
| Institución: | Universidad de Barcelona |
| Repositorio: | Dipòsit Digital de la UB |
| OAI Identifier: | oai:diposit.ub.edu:2445/106622 |
| Acceso en línea: | https://hdl.handle.net/2445/106622 http://hdl.handle.net/10803/399911 |
| Access Level: | acceso abierto |
| Palabra clave: | Compostos de coordinació Fotoquímica orgànica Coordination compounds Organic photochemistry |
| Sumario: | [eng] One of the main objectives of this thesis was the synthesis of new chelating ligands containing a photochromic unit able to change its conformation upon light irradiation. This isomerization should serve to modify the magnetic behavior of the new coordination compounds, formed upon reaction of transition metals or lanthanides, assembled within the phtochromic ligands. Whith these aims, the synthesis of 5 new ligands has been achieved, which have been characterized successfully. Subsequently, the preparation of 22 coordination compounds with these ligands has been accomplished. The crystallographic study of these coordination compounds has been very important for the complete understanding of the magnetic and photohromic properties. Regarding the crystal structures, in Chapter 1, the distinct photochromic properties of the complexes discussed was rationalized in light of the structural information. The results show that crystal design may constitute an interesting way for modulating the properties of the solid state photoactivity. Two new ligands were synthesized in Chapter 3, based on beta diketone moieties, which additionally, are functionalized with a phenol group. Those groups together form an excellent chelating pocket to introduce metal arrays. Importantly, those arrays can be formed as pair of heterometallic dimers, whose ground state exhibit in some cases S=1/2 systems, thus providing a pair of spins ½ well defined within the molecule. This feature can be exploited in the context of quantum computing by studying the quantum coherence of these spin. Indeed, coherence times of thousands of nanosecond can be measured at low temperature.. Two other new ligands, have been presented in Chapter 4. These have been synthesized via Schiff base condensation. Similar two the beta diketones, these ligands are able to perform fast and excellent photochromism, in addition to the cis/trans isomerizations that can undergo themselves. While those isomerizations have not been studied, they could be used as gate-reactivity, adding more versatility to these compounds. The chelating pockets of these ligands are very useful regarding to the coordination ability with lanthanides and transition metals. Single molecule magnet behavior has been observed in a dysprosium cluster. Finally, in Chaper 5, the synthesis of a new photochromic ligand containing a pyridine-pyrazole moiety, has been tested for the preparation of a Fe(II) spin crossover helical system. This has shown to be a good candiadate as part of new hybrid devices, because the excellent resistance to the fatigue, the different fluorescent behavior and the SCO features. |
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