Face-Directed Construction of a Metal-Organic Isohedral Tetrahedron for the Highly Efficient Capture of Environmentally Toxic Oxoanions and Iodine.

Geometric analysis has been guiding the design and construction of metal-organic polyhedra. Here, a series of isohedral tetrahedra ZrIT-1 and -2 and VIT-1 and -2 were synthesized by a one-pot method relying on trivalent molecular building blocks. Structural analysis shows that the isohedral tetrahedra constructed with {V 6 (SO 4 )(CO 2 ) 3 } have three different sets of prism lengths, while those constructed with {Zr 3 O(CO 2 ) 3 } have two different sets of prism lengths. Comparison of two types of polyhedra reveals that the different sizes and coordination flexibilities of the two MBBs result in different cavity volumes. The environmentally toxic oxoanion trapping ability of ZrIT-1 was explored due to its structural stability and cation cage properties. The results show that ZrIT-1 can capture permanganate and dichromate anions in water with high efficiency and selectivity. Notably, the permanganate adsorption capacity can reach ∼276.6 mg/g, which exceeds those of most metal-organic framework materials. In addition, the adsorption and desorption of iodine showed that ZrIT-1 has a reversible adsorption capacity for iodine.