Synthesis and Characterization of Amphiphilic Donor-Acceptor Architectures Hybrids Based on Rylene-Porphyrin Hybrids: Towards Charge Separation of Supramolecular Aggregates in Water

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In this project, the synthesis, supramolecular assembly and photophysical behavior of a family of unprecedented amphiphilic rylene-porphyrin donor-acceptor (D-A) derivatives will be investigated. The goal is to achieve control over the self-assembly behavior of these compounds, which is essential for photo induced charge separation of aggregates and membranes in water. Assembly in aqueous media achieved through tailoring the molecular structure will give rise to strictly ordered architectures driven by hydrophobic interactions. These unprecedented systems will also act as model compounds for investigating key steps in photosynthesis. To achieve this, we will synthesize unprecedented bola-amphiphiles in a methodical tool-box approach, which also allows for the introduction of a variety of functional groups. Further, we will systematically investigate the influence of the selected functional groups, which change the geometry end electronic properties of the single amphiphile, regarding the assembly of the superstructure and the photophysical characteristics. These distinct architectures can generate a variety of possible supramolecular arrangements in water such as liposomes, micelles, and helical columns. Consequently, the influence of the supramolecular structure on the photophysical behavior, in particular, the photo-induced charge separation within the aggregates will be studied. Moreover, the incorporation of small molecules into the supramolecular structure will be investigated. Taking the inclusion of a second non covalent interaction even further, the stabilization of the rylenebisimide chromophore itself in an aqueous environment through hydrogen-bonding motifs will be explored. The synthetic approach is going to revolve around trans-meso substituted porphyrins, which will be connected to the rylene core and the hydrophilic periphery. To achieve the required hydrophilicity, dendritic structures bearing carboxylic acid groups will be utilized. Subsequently, thorough structural and photophysical characterization of these systems and their aggregates will be carried out, for example, with cryo transmission electron microscopy (TEM), steady-state, and time resolved optical spectroscopy.