Mimicking Photosystem I with a Transmembrane Light Harvester and Energy Transfer‐Induced Photoreduction in Phospholipid Bilayers
Andrea Pannwitz, Holden Saaring, Nataliia Beztsinna, Xinmeng Li, Maxime A. Siegler, Sylvestre Bonnet
Abstract
Abstract 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.