Stepwise post-synthetic linker installation in rare-earth metal–organic frameworks

Abstract

Metal–organic frameworks based on rare earth elements (i.e. RE-MOFs) represent an important class of porous crystalline materials that have gained increasing attention due to their diverse optical, photophysical, and electronic properties. Developing strategies to enrich their properties is of great interest to expand their applications. Post-synthetic installation of secondary linkers to RE-MOFs, in principle, is an effective approach to incorporate new functionalities of RE-MOFs. However, the lack of synthesis control to generate RE-MOFs that consist of less connected clusters for linker installation limits the utility of this methodology. Herein, a co-modulator strategy was successfully used to synthesize RE-MOFs consisting of 8-connected RE₆ clusters with scu topology. These new RE-MOFs allow the precise installation of different secondary linkers including photosensitizers along the a and c crystallographic axes via single-crystal-to-single-crystal transformation, and the resulting RE-MOFs exhibit either enhanced or inhibited energy transfer depending on the energy level of the inserted linker. Our work provides an effective approach for the design and synthesis of multifunctional RE-MOFs.