Stepwise Assembly of Quinary Multivariate Metal-Organic Frameworks via Diversified Linker Exchange and Installation

Multivariate MOFs (MTV-MOFs) constructed from multiplecomponentswith atomistic precision hold the promise for many fascinating developmentsin both fundamental sciences and applications. Sequential linker installationcan be an effective method to introduce different functional linkersinto an MOF that contains coordinatively unsaturated metal sites.However, in many cases, these linkers must be installed accordingto a specific sequence and the complete synthetic flexibility andfreedom is yet to be realized. Here, we rationally decreased the sizeof the primary ligand used in NPF-300, a Zr-MOF with scu topology (NPF = Nebraska Porous Framework), and synthesized itsisostructure, NPF-320. NPF-320 exhibits optimized pocket sizes whichallow for the post-synthetic installation of three secondary linkersin all six permuted sequences via both linker exchange and installation,forming a final quinary MTV-MOF via single-crystal-to-single-crystaltransformation. With the functionalization of the linkers from thequinary MOF system, one will be able to construct MTV-MOFs not onlywith variable porosity but also with unprecedented complexity andencoded synthetic sequence information. The utility of sequentiallinker installation was further demonstrated by the construction ofa donor-acceptor pair-based energy transfer system.

Automated summary

By reducing the size of the primary ligand, we synthesized NPF-320, a Zr-MOF with optimized pocket sizes. This MOF allows for the post-synthetic installation of three secondary linkers in all six permuted sequences, forming a quinary MTV-MOF. With the functionalization of these linkers, we can construct MTV-MOFs with variable porosity and unprecedented complexity and encoded synthetic sequence information.