A magnesium phosphonate metal-organic framework showing excellent performance for lead(II) sensing and removal from aqueous solutions.

A hydrogen-bonded three-dimensional porous metal-organic framework [Mg(H 2 PCD) 2 (H 2 O) 2 ]·2H 2 O (denoted as Mg-MOF·2H 2 O; H 3 PCD = 9-(2-(ethoxy(hydroxy)phosphonyl)ethyl)-9 H -carbazole-3,6-dicarboxylic acid) was synthesized by the reactions of H 3 PCD and Mg(II) under solvothermal conditions. The free carboxylate group was maintained in the pore surface by adjusting the acidic reaction conditions. The highly stable Mg-MOF exhibits excellent performance for lead(II) sensing and removal from aqueous solutions.