Hg2+-selective ratiometric and "off-on" chemosensor based on the azadiene-pyrene derivative.

A new pyrene-based derivative bearing an azadiene group was synthesized as a ratiometric chemosensor for Hg(2+) in aqueous acetonitrile solution. The "off-on" type signaling behavior of the fluoroionophore is due to the metal ion induced conformational changes from the weak pyrene monomer emissions to strong pyrene excimer emission.