Postsynthetic construction of molecular chromophore-DNA-architectures as light harvesting systems for photocatalysis

• Applicant: Professor Dr. Hans-Achim Wagenknecht
• Subject Area: Organic Molecular Chemistry - Synthesis and Characterisation
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 555940396

The generation of energy from renewable sources, preferably from sunlight, has become one of the most important projects of the "energy turnaround" to reduce the need for unsustainable fossil energy sources. For such a system change in synthetic chemistry, inorganic/organic chromophores organic chromophores or entire ensembles of chromophores absorb light as synthetic antennas. For this purpose, DNA offers a still little researched programmed and hierarchically ordered bottom-up arrangement of light-absorbing chromophores in supramolecular DNA architectures. Within this project, chromophore-modified nucleoside building blocks as monomers are to be placed sequence-controlled into covalently linked chromophore-DNA architectures. The synthesis goal of this project is a post-synthetic approach with pre-synthesized ethynylated oligonucleotides, which are sequence-specifically modified with different chromophores via copper- and palladium-catalyzed Sonogashira coupling. The photochemical significance of this project in terms of basic research lies in the scientific gain of knowledge from the individual chromophores to the DNA-based architectures in order to work out the potential of DNA as a supramolecular structure former. Furthermore, fundamental insights into the energy and electron transfer in these DNA architectures as light-harvesting systems will be gained. As an example, the triplet-triplet upconversion of visible light into UV light by the DNA light-harvesting systems will be realized and tested on photocatalysis in both aqueous and organic solvents.

• DFG Programme: Research Grants