A Significant Fluorescence Quenching of Anthrylaminobenzocrown Ethers by Paramagnetic Metal Cations

Molecular systems that combine binding ability and photo-physical properties are of great interest for designing new chemosensors and molecular devices. The process involving energy transfer in the separated large molecules is of current interest.1 The methods applied to such studies involve the fluorescence quenching, excimer or exciplex emission, and charge transfer (CT) or photoinduced electron transfer (PET) complex emission. It has been well established that energy transfer through the fluorescence quenching proceeds via the formation of an exciplex with CT or PET character.2 The flow of charge or electron, either from the fluorophore to the quencher or from the quencher to the fluorophore de-pends upon the oxidation and reduction potential of respec-tive species. The most commonly employed fluorescent chemosensor is one in which a fluorophore and a recepto