Light-driven electron transfer in a lipid bilayer with mixed valence molecular wires

Abstract

Triarylamines (TAAs) are one of the most important classes of redox-active organic compounds, which are readily available from modular synthesis, thereby offering the possibility to easily adjust their intrinsic redox potentials. We present herein two bis(triarylamines) (BTAAs) with π-extended 2,7-diethynylfluorene or 2,2′-(1,3-butadiyne-1,4-diyl)-bis(7-ethynylfluorene) bridges and two benzoic acid headgroups per TAA and their (formally) mixed-valent radical cations. Owing to their amphiphilic character and favorable redox properties, these BTAAs are designed to serve as charge conduits through membranes. The lipid bilayer/BTAA systems are water-soluble, which allowed us to explore their photoactivity in aqueous solution and utilize their mixed valent form for membrane-mediated photoinduced electron transfer. Our findings will be relevant for constructing artificial nanoreactors for solar light energy conversion and light-driven redox chemistry in water.