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 2
O 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.