A novel ditopic chromogenic receptor, N-5-(8-hydroxy) quinoline-N′-4′-nitro-phenyl thiourea (1), was synthesized. The metal complex 1-Hg2+ showed sensitive and highly selective responses to F− over other anions such as CH3CO2−, H2PO4−, HSO4− and Cl−. 1- Hg2+–F− complex formed, which promoted the intramolecular charge transfer and led to a dramatic spectral change. The color of 1-Hg2+ solution changed from colorless to red ...
