Interaction of multi-podal open-chained compounds with anions

Six kinds of naphthyl urea and thiourea podands were designed and synthesiz ed. The interaction between these compounds and various guest anions are st udied in molecular level via absorption, fluorescence and H-1 NMR spectra. The experiments show that tri-podal urea or thiourea host can bind H2PO4- o r HSO4- selectively and form a host-guest complex thus inducing a change in photophysical properties of host molecule. Through comparison between urea and thiourea compounds used as host molecules, the stability constants and stoichiometry of the complexes have been determined. The binding manner an d possible structures of them have been proposed.