Discovery of Zr-based metal-organic polygon: Unveiling new design opportunities in reticular chemistry

Metal-based secondary building unit and the shape of organic ligands are the two crucial factors for determining the final topology of metal-organic materials. A careful choice of organic and inorganic structural building units occasionally produces unexpected structures, facilitating deeper fundamental understanding of coordination-driven self-assembly behind metal-organic materials. Here, we have synthesized a triangular metal-organic polygon (MOT-1), assembled from bulky tetramethyl terephthalate and Zr-based secondary building unit. Surprisingly, the Zr-based secondary building unit serves as an unusual ditopic Zr-connector, to form metal-organic polygon MOT-1, proven to be a good candidate for water adsorption with recyclability. This study highlights the interplay of the geometrically frustrated ligand and secondary building unit in controlling the connectivity of metal-organic polygon. Such a strategy can be further used to unveil a new class of metal-organic materials.