Template-Designed Synthesis of Open-Framework Zinc Phosphites with Extra-Large 24-Ring Channels

摘要

The rational selection of the templating agents or structure-directing agents (SDAs) is important for the designed synthesis of open-framework materials with specific channel structures. By utilizing organic amines that are predicted by computer simulations using Materials Studio software and Cerius package as the templates or SDAs, such as cyclohexanamine (CHA), cyclopentylamine (CPA), and n-propylamine, three new open-framework zinc phosphites, including (C6H14N)2[Zn3(HPO3)4] (ZnHPO-CJ2), (C5H12N)2[Zn3(HPO3)4] (ZnHPO-CJ3), and (C3H10N)2[Zn3(HPO3)4] (ZnHPO-CJ4), have been hydrothermally prepared with desired extra-large 24-ring channels analogous to (C4NH12)2[Zn3(HPO3)4] (ZnHPO-CJ1). Their structures are characterized by single-crystal and powder X-ray diffraction, ICP, IR, and TG analyses. These organic amines predicted based on non-bonding interactions of host-guest show good matching in the space and charge density with the host inorganic framework. As with ZnHPO-CJ1 and other known extra-large micropore materials with high framework charge density, the 24-rings of these compounds are assembled around multiple small amines, exemplifying the cooperative templating mechanism of multiple small organic cations in the formation of extra-large micropore open-framework materials. This work demonstrates a useful strategy toward the template-designed synthesis of microporous materials with extra-large micropores.