Desarrollo de nuevos sistemas quirales: estudio de sus propiedades optoelectrónicas

Resum

The first part is about the study of different flexible helical structures based on an ortho-oligophenylene ethylene (o-OPE) scaffold with a chiral staple which is able to induce one helicity preferentially, obtaining enantiopure compounds. In the general background, a summary about parent molecules reported previously by our group is given. Besides, it is discussed aspects such as what their potential impact is or what new scientific challenges based on them are. Later, four chapters are found. The first of them is based on synthesis of a new extended o-OPE family, that is, longer o-OPE compounds. Their chiroptical properties and the relationship between such properties and CISS effect are studied. These compounds lose their helicity when distance between the main chain and the chiral staple increases. It leads to a second part in this chapter, where arene-perfluoroarene interactions are used as stronger non-covalent intramolecular interactions. With this strategy, a better helicity is achieved, and chiroptical properties are increased without needing coordination with metals. In the second chapter, shorter derivatives of the family are studied, keeping the same central enantiopure stapled o-OPE scaffold, but introducing different substituents in both ends of structures. The aim here is to tune these helixes in order to make them useful in different applications, such as molecular electronic and chiral metallosupramolecular arquitectures. In this way, a new and more efficient molecular potentiometer is designed. Furthermore, its chirality opens the door to study experimental CISS effect in this kind of molecules. On the other hand, a new metallosupramolecular structure is described as a chiral Pd2L2 ring. In the third chapter, the purpose is to design the first CPL and spin-dependent barcode. It would allow to encode chiral information and to read it quickly and reliably with proper instrumentation. For it, an enantiopure o-OPE compound reported previously by our group is selected. Their deposition in thin-films is carried out by Langmuir deposition method, and its chiroptical and electronic properties are studied. In the fourth and last chapter of this part, in order to improve the chiroptical properties of these shorter and/or more flexible derivatives o-OPE and the efficiency of these spin filters, extended and more rigid structures are designed and synthesized. Thus, the combination of two monomers, one stapled o-OPE and one [6]helicene, is used and its helicity is maintained through the backbone. This would allow further studies about longer and longer enantiopure oligomers by alternating such monomers. The second part is shorter and it is focus on the development of rigid helical structures, more specifically, helicenes. These helixes provide chirality to known emitter scaffolds which are useful as sensors in bioimaging applications. Thus, the first section gives an overview of such molecules and the reasons why they are currently interesting in research. Subsequently, the only chapter in this part is developed, starting with a summary of emitter sensors previously reported by our group. Here, the aim is the introduction of chirality in a sensor as an additional feature. It would allow improving the specificity of the technique, being able to distinguish this fluorophore in the presence of others by means of CPL. For it, two similar compounds derived from a xanthenic scaffold bearing a [6] helicene are designed. They are synthesized and their photophysic and chiroptical properties are studied. Finally, an annexed with a list of publications is provided. It shows both the own results of this thesis and others obtained in different collaborations along the predoctoral period. In addition, references of non-original images used in this memory are collected.