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-α and ZrT-1-β, ZrT-2-α, and ZrT-2-β). Compared to the fragile α-phase competitors, the β-phase aggregations not only exhibit a higher ratio of O–H···Cl – bond, but also contain a stronger bridging hydrogen bond. Consequently, although ZrT-1-β and ZrT-2-β contain higher porosity, they show enhanced stability in the guest-free state.