ANION RECOGNITION BY A PYRENE DERIVATIVE WITH A THIOUREA FUNCTION

A novel fluorescent indicator for anions, which contains both a fluore scent pyrenyl moiety and a thiourea group as a recognition site, is de scribed. Hydrogen bond-mediated complexation with oxo anions such as C H3COO- and H2PO4- induces a dual fluorescence consisting of two bands, namely, a normal emission due to the pyrene unit and an anomalous lon g-wavelength emission. The intensity of the new emission increases as anion concentration increases, while the normal emission is relatively unaffected. The degree of the changes is in the order of CH3COO-> H2P O4->> ClO4-, reflecting the binding selectivity of the probe molecule.