Construction of Flexible-on-Rigid Hybrid-Phase Metal-Organic Frameworks for Controllable Multi-Drug Delivery.

Multi-component MOFs contain multiple sets of unique and hierarchical pores, with different functions for different applications, distributed in their inter-linked domains. Herein, we report the construction of a class of precisely aligned flexible-on-rigid hybrid-phase MOFs with a unique rods-on-octahedron morphology. We demonstrated that hybrid-phase MOFs can be constructed based on two prerequisites: the partially matched topology at the interface of the two frameworks, and the structural flexibility of MOFs with acs topology, which can compensate for the differences in lattice parameters. Furthermore, we achieved domain selective loading of multiple guest molecules into the hybrid-phase MOF, as observed by scanning transmission electron microscopy-energy-dispersive X-ray spectrometry elemental mapping. Most importantly, we successfully applied the constructed hybrid-phase MOF to develop a dual-drug delivery system with controllable loading ratio and release kinetics.