A new phosphorescent chemosensor bearing Zn-DPA sites for H2PO4−

• An iridium (III) complex bearing two Zn-DPA units displayed selective phosphorescence change for H2PO4−.
• The iridium (III) complex showed a selective phosphorescence enhancement with H2PO4− in 100% aqueous solution at pH 7.4.
• The iridium complex showed selectivity for H2PO4− over simple anions as well as ATP and pyrophosphate.

A phosphorescence chemosensor bearing an iridium (III) complex as a communicating source and two Zn-DPA units acting as a preorganized binding site for H2PO4− is presented. The phosphorescent chemosensor displayed a selective phosphorescence enhancement with H2PO4− in aqueous solution and at neutral pH. On the other hand, F−, Cl−, Br−, I−, NO3−, CH3COO−, and ClO4− did not induce significant changes in phosphorescence. Furthermore, the phosphorescent chemosensor shows selectivity for H2PO4− over the related phosphate species, such as ATP and pyrophosphate. In addition, there was a distinct lifetime change only for H2PO4−. The association constant was calculated to be 9.68 × 104 M−1 for H2PO4−.

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