Competition Between Energy Transfer Quenching and Chelation Enhanced Fluorescence in a Cu (II) Coordinated Conjugated Polymer System
writer：Li-Juan Fan ; Martin. J. Justin; Wayne E. Jones
keywords：Conjugated polymer , Fluorescent chemosensor ,Chelation enhanced fluorescence ,Energy transfer quenching,Dexter (double-electron exchange) energy transfer
source：期刊
specific source：J. Fluoresc.
Issue time：2009年
An investigation of the mechanism of the fluorescence quenching by Cu2+ for a conjugated polymer system initially designed as a fluorescence turn-on chemosensor based on chelation enhanced fluorescence (CHEF) is described in this paper. Unlike all other metal cations tested, the polymer/Cu2+ hybrid system with a 1:1 ratio between the receptor and Cu2+ has only weak fluorescence with λmax = 490 nm and a quantum yield of 0.004 in THF at room temperature. In solvent glasses at 77 K the fluorescence remained quenched suggesting that the quenching mechanism was due to energy transfer between the Cu2+ and the conjugated polymer backbone. The energy transfer quenching competes effectively with the electron transfer involved in the CHEF resulting in a more selective chemosensory system.