Mimicking Photosystem I with a Transmembrane Light Harvester and Energy Transfer‐Induced Photoreduction in Phospholipid Bilayers

Photosystem I (PS I) is a transmembrane protein that assembles perpendicular to the membrane, and performs light harvesting, energy transfer, and electron transfer to a final, water‐soluble electron acceptor. We present here a supramolecular model of it formed by a bicationic oligofluorene 1(2+) bound to the bisanionic photoredox catalyst eosin Y (EY(2−)) in phospholipid bilayers. According to confocal microscopy, molecular modeling, and time dependent density functional theory calculations, 1(2+) prefers to align perpendicularly to the lipid bilayer. In presence of EY(2−), a strong complex is formed (K(a)=2.1±0.1×10(6) m (−1)), which upon excitation of 1(2+) leads to efficient energy transfer to EY(2−). Follow‐up electron transfer from the excited state of EY(2−) to the water‐soluble electron donor EDTA was shown via UV–Vis absorption spectroscopy. Overall, controlled self‐assembly and photochemistry within the membrane provides an unprecedented yet simple synthetic functional mimic of PS I.