title: Competition between energy transfer quenching and chelation enhanced fluorescence in a Cu (II) coordinated conjugated polymer system.
abstract: An investigation of the mechanism of the fluorescence quenching by Cu(2+) 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/Cu(2+) hybrid system with a 1:1 ratio between the receptor and Cu(2+) has only weak fluorescence with lambda(max) = 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 Cu(2+) 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.
authors.affiliation: Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials, Soochow University, Suzhou, 215123, People's Republic of China. ljfan@suda.edu.cn
authors.forename: Li-Juan
authors.initials: LJ
authors.lastname: Fan
authors.forename: Justin J
authors.initials: JJ
authors.lastname: Martin
authors.forename: Wayne E
authors.initials: WE
authors.lastname: Jones
mesh_terms: D000480:Alkynes / Q000737:chemistry; D002614:Chelating Agents / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D004735:Energy Transfer; D004987:Ethers / Q000737:chemistry; D005453:Fluorescence; D009942:Organometallic Compounds / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013696:Temperature; D017186:Titrimetry; D014867:Water / Q000737:chemistry
chemical_list: D000480:Alkynes; D002614:Chelating Agents; D004987:Ethers; D009942:Organometallic Compounds; D011108:Polymers; C436384:phenyleneethynylene; D014867:Water; D003300:Copper