A molecular chemodosimeter to probe "closed shell" ions in kidney cells.

Two quinidine-functionalized coumarin molecular probes have been synthesized and have been found to bind metal cations (Cd, Co, Cu, Fe, Hg, Ni, and Zn) with high affinity in organic-aqueous media (DMSO-HEPES). The chemodosimeters coordinate with the Zn ions in a two-to-one ratio (molecular probe : Zn) with a log  of 10.0 M. Upon the addition of the closed-shell metal ions studied, a fluorescence turn-on an excimer formation is seen at 542 nm due to the quinaldine moiety adopting a arrangement when coordinated to the metal Zn ions. Confocal microscopy monitored free Zn ions in the Human Embryonic Kidney cell line HEK293 by coordinating with the chemodosimter.