Triphosphate Ion-Selective Electrode Based on Zr-Porphyrin Complex.

Ion-selective electrode using zirconium(IV) complex with octaethylporphin (Hoep) as a carrier showed high selectivity to triphosphate (TP, Htp) against other hydrophilic anions including diphosphate and phosphate. The electroactive species was identified to be [(Zr(oep)(Htp)] (TP/Zr ratio of 0.5) of the unique structure; triphosphates are recognized by one Zr atom through three O atoms on three different P atoms and by another Zr atom through two O atoms on two terminal P atoms and are also involved in complementary intermolecular hydrogen bonding to be surrounded by four porphyrin complexes.