Interrupted Zeolite LTA and ATN-Type Boron Imidazolate Frameworks

Zeolite A (LTA) is of much interest in zeolite family because of its large-scale industrial applications. Making Zeolite A (a typical 4-connected tetrahedral framework material) with a lower connectivity (3-connected) might lead to new open architecture with expanded ring size and enhanced functionality. The first interrupted Zeolite A with 3-connected network has been experimentally realized here by a boron imidazolate (im) framework material (BIF-20) with 3-coordinate BH(mim)3– building units. Additionally, a new strategy toward the construction of functional microporous metal–organic frameworks with interrupted zeolite-type topologies is presented by both 3-connected boron imidazolate frameworks (BIF-20 and BIF-21). BIF-20 has an unusual tetrahedral framework with both debonded α and β cages, and exhibits high H2 uptake capacity.在沸石家族中，A型沸石（Zeolite A，LTA拓扑结构）因其大规模的工业应用而备受关注。将作为典型四连接四面体骨架材料（4-connected tetrahedral framework material）的A型沸石制备为低连接度（3-connected）结构，有望获得环孔尺寸扩大、功能增强的新型开放骨架。本研究通过以三配位BH(mim)₃⁻为结构基元（building units）的硼咪唑盐（boron imidazolate，im）骨架材料BIF-20，首次实验合成得到具有三连接网络的中断型A型沸石。此外，本研究还提出了一种构建具有中断型沸石类拓扑结构的功能性微孔金属有机骨架（microporous metal–organic frameworks）的新策略，该策略可适用于两类三连接硼咪唑盐骨架材料：BIF-20与BIF-21。其中，BIF-20拥有兼具脱键α笼与β笼的非常规四面体骨架，并表现出较高的氢气吸附容量（H2 uptake capacity）。