Isotopological entanglement of a metal-organic framework and a hydrogen-bonded organic framework for proton conduction

Framework structures such as metal-organic frameworks (MOFs) and hydrogen-bonded organic frameworks (HOFs) can facilitate proton conduction through various proton-carrying sites within the pores or along the backbones, demonstrating their viability as proton-conducting materials for fuel cells. However, the lack of inherent proton-carrying sites on typical MOF backbones and the architectural instability of HOFs pose a challenge for further applications. Here we report the synthesis of a framework that complementarily entangles a MOF and HOF through meticulous control of the deprotonation equilibrium of the linker. The hybrid entangled framework shows higher architectural stability than the MOF net alone through the mutual support of the two isotopological nets. Furthermore, the HOF architecture and plentiful H2O molecules in the well-sized channels provide a proton conductivity of 1.1 x 10-2 S cm-1 at 95 degrees C and 100% relative humidity. The crossover of different porous frameworks provides a method to integrate various materials seamlessly into a cohesive and functional system.