Photon antennas: self-assembly of donor and acceptor metal ions at the galleries of layered alpha-zirconium phosphonates

Donor and acceptor metal ions are self-assembled by coordination to the car boxylate functions of the alpha-carboxyethyl zirconium phosphonate (alpha-Z rCEP). Uranyl and europium ions, for example, bind to the carboxyl function s of alpha-ZrCEP at stoichiometric amounts (2:1, carboxylate to metal ion). Selective excitation of uranyl (donor) with visible light (430 nm) resulte d in efficient energy transfer from the donor excited states to europium(II I) (acceptor). Sensitized emission from the acceptor was observed at 590 nm and the quenching efficiencies are estimated from the luminescence experim ents. Binding of the donors and accepters to the matrix resulted in enhance d energy transfer from the donor to the acceptor when compared to the solut ion phase studies. The quenching efficiencies increase dramatically with do nor concentration as direct evidence for the donor-to-donor energy migratio n within the assemblies of the metal ions. Such systems that function with visible light may be of interest in photonics, and in solar energy harvesti ng. (C) 1999 Elsevier Science B.V. All rights reserved.