One‐Pot Synthesis of MOF@MOF: Structural Incompatibility Leads to Core–Shell Structure and Adaptability Control Makes the Sequence

Abstract Core–shell metal–organic frameworks (MOF@MOF) are promising materials with sophisticated structures that cannot only enhance the properties of MOFs but also endow them with new functions. The growth of isotopic lcore–shell MOFs is mostly limited to inconvenient stepwise seeding strategies with strict requirements, and by far one‐pot synthesis is still of great challenge due to the interference of different components. Through two pairs of isoreticular MOFs, it reveals that the structural incompatibility is a prerequisite for the formation of MOFs@MOFs by one‐pot synthesis, as illustrated by PMOF‐3@HHU‐9. It further unveils that the adaptability of the shell‐MOF is a more key factor for nucleation kinetic control. MOFs with flexible linkers has comparably slower nucleation than MOFs with rigid linkers (forming PMOF‐3@NJU‐Bai21), and structural‐flexible MOFs built by flexible linkers show the lowest nucleation and the most adaptability (affording NJU‐Bai21@HHU‐9). This degree of adaptability variation controls the sequence and further facilitates the synthesis of a first triple‐layered core–shell MOF (PMOF‐3@NJU‐Bai21@HHU‐9) by one‐pot synthesis. The insight gained from this study will aid in the rational design and synthesis of other multi‐shelled structures by one‐pot synthesis and the further expansion of their applications.