Solvent effect on the fluorescence response of hydroxycoumarin bearing a dipicolylamine binding site to metal ions.
The fluorescence behavior of a probe dpa-HC, which has a coumarin derivative that acts as a fluorophore and a dipicolylamine (DPA) unit that functions as a metal ion-recognition site, was investigated with various metal ions in aqueous and several non-aqueous solvents. In aqueous solution, the fluorescence of dpa-HC was enhanced by Zn(2+) and Cd(2+), but was quenched by other metal ions. On the other hand, in an acetonitrile solution, only Mg(2+) enhanced the fluorescence, and the addition of a small amount of water quenched this fluorescence. This dramatic selectivity change is explained by stabilization of a metal-dpa-HC complex due to acetonitrile coordination and ON-OFF switching of the intramolecular photoinduced electron transfer (PET) from the nitrogen lone pair of DPA to the coumarin derivative.
Department of Materials and Life Sciences, Faculty of Science and Technology, Sophia University.
Hiroyuki
H
Kobayashi
Kohei
K
Katano
Takeshi
T
Hashimoto
Takashi
T
Hayashita
D000097:Acetonitriles / Q000737:chemistry; D000588:Amines / Q000737:chemistry*; D001665:Binding Sites; D003374:Coumarins / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry*; D008670:Metals / Q000737:chemistry*; D010848:Picolinic Acids / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D014867:Water / Q000737:chemistry
C501847:2,2'-dipicolylamine; D000097:Acetonitriles; D000588:Amines; D003374:Coumarins; D005456:Fluorescent Dyes; D008670:Metals; D010848:Picolinic Acids; D012997:Solvents; D014867:Water; C030123:coumarin; C032159:acetonitrile