Self-Assembled Fluorescent Pt(II) Metallacycles as Artificial Light-Harvesting Systems

Abstract

Light-harvesting is one of the key steps in photosynthesis, while, developing artificial light-harvesting systems (LHSs) with high energy transfer efficiencies has been a challenging task. Here we report fluorescent hexagonal Pt(II) metallacycles as a new platform to fabricate artificial LHSs. The metallacycles ( 4 and 5) are easily accessible by coordination driven self-assembly of a triphenylamine-based ditopic ligand 1 with di-platinum acceptors 2 and 3, respectively. They possess good fluorescence properties both in solution and in the solid state. Notably, the metallacycles show aggregation induced emission enhancement characteristics (AIEE) in a DMSO-H ₂O solvent system. In the presence of a fluorescent dye Eosin Y (ESY), the emission intensities of the metallacycles decrease but the emission intensity of ESY increases. The absorption spectrum of ESY and the emission spectra of the metallacycles show a considerable overlap, suggesting the possibility of energy transfer from the metallacycles to ESY, with an energy transfer efficiency as high as 65% in the 4 ^a +ESY system.

Graphical Abstract