A General Strategy for Hollow Metal-Phytate Coordination Complex Micropolyhedra Enabled by Cation Exchange

The ability to incorporate functional metal ions (Mⁿ⁺) into metal–organic coordination complexes adds remarkable flexibility in the synthesis of multifunctional organic–inorganic hybrid materials with tailorable electronic, optical, and magnetic properties. We report the cation-exchanged synthesis of a diverse range of hollow Mⁿ⁺-phytate (PA) micropolyhedra via the use of hollow Co²⁺-PA polyhedral networks as templates at room temperature. The attributes of the incoming Mⁿ⁺, namely Lewis acidity and ionic radius, control the exchange of the parent Co²⁺ ions and the degree of morphological deformation of the resulting hollow micropolyhedra. New functions can be obtained for both completely and partially exchanged products, as supported by the observation of Ln³⁺ (Ln³⁺=Tb³⁺, Eu³⁺, and Sm³⁺) luminescence from as-prepared hollow Ln³⁺-PA micropolyhedra after surface modification with dipicolinic acid as an antenna. Moreover, Fe³⁺- and Mn²⁺-PA polyhedral complexes were employed as magnetic contrast agents.