Artificial light-harvesting systems based on self-assembled fluorescent palladium(II)-metallacycle in aqueous solution.

Light harvesting is one of the fundamental steps in photosynthesis, and developing artificial light harvesting systems (LHSs) with high energy transfer efficiency is still a challenging task. Herein, we designed and constructed a novel fluorescent tetragonal Pd(II)-metallacycle (DDPH-Pd) as a new platform for the construction of artificial LHSs. 6,15-bis(pyridine)-9,12-bis(dodecyloxy)-substituted benzo[5]helicene (DDPH) and ethylenediamine palladium nitrate were coordinated to generate self-assembled DDPH-Pd. Carmosine and Nile red were chosen as acceptors due to their good spectral overlap with that of DDPH-Pd , which is essential for fabricating light-harvesting system. The artificial LHSs show good energy transfer efficiency (61%) and antenna efficiency (5.0) in Carmosine@ DDPH-Pd with a 50:1 donor/acceptor ratio. [Display omitted] • The new fluorescent metallacycles is assembled by the bipyridine ligand DDPH and ethylene-diamine palladium nitrate. • Amphipathic metallacycles further aggregate in water to form nano spheres. • The Pd(II)-metallacycles are used as a new platform for the construction of artificial light harvesting systems. • LHSs have good energy transfer efficiency (61%) and antenna efficiency (5.0) with donor/acceptor ratio of 50:1. [ABSTRACT FROM AUTHOR]