Hydrogen-Bonded Framework Isomers Based on Zr-Metal Organic Cage: Connectivity, Stability, and Porosity

The construction of hydrogen-bonded frameworks from simple molecular tectons attracts widespread attention; however, it is still challenging to construct hydrogen-bonded framework isomers in a controllable way. On the basis of our previous work, via increasing the bridging hydrogen bond ratio and strength between Zr-metal organic cage (Zr-MOC), we report here two pairs of Zr-MOC based hydrogen-bonded framework isomers with different stabilities and porosities (ZrT-1-alpha and ZrT-1-beta, ZrT-2 alpha, and ZrT-2-beta). Compared to the fragile a-phase competitors, the beta-phase aggregations not only exhibit a higher ratio of O-H center dot center dot center dot Cl- bond, but also contain a stronger bridging hydrogen bond. Consequently, although ZrT-1-beta and ZrT-2-beta contain higher porosity, they show enhanced stability in the guest-free state.