Chelation of specific metal ions imparts coplanarity and fluorescence in two imidazo[1,2-a]pyridine derivatives: Potential chemosensors for detection of metal ions in aqueous and biosamples

Abstract Synthesis and chelation induced fluorescence emission from two imidazo[1,2- a ]pyridine derivatives are described. The nonfluorescent molecule 1 containing N and O donor atoms, achieves coplanarity upon interactions with trivalent cations Al 3+ , Fe 3+ and Cr 3+ , that favors fluorescence emission. Molecule 2 containing two N donor atoms attains coplanarity upon interaction with the only Zn 2+ and becomes fluorescent. Both molecules 1 and 2 form a 1:1 complex with interacting metal ions. Other trivalent metal ions (including Bi 3+ and In 3+ ) and common divalent metal ions (including Hg 2+ and Cd 2+ ) fail to form any complex with 1 or 2 , and they do not interfere in the detection of Zn 2+ , Al 3+ , Fe 3+ or Cr 3+ ions. Noninterference of other metal ions renders 1 and 2 suitable for the detection of fungal cells contaminated with Zn 2+ , Al 3+ , Fe 3+ or Cr 3+ ions.