Applying reticular synthesis to the design of Cu-based MOFs with mechanically interlocked linkers

The concept of robust dynamics describes the incorporation of mechanically interlocked molecules (MIMs) into metal-organic framework (MOF) materials such that large amplitude motions (e.g., rotation or translation of a macrocycle) can occur inside the free volume pore of the MOF. To aid in the preparation of such materials, reticular synthesis was used herein to design rigid molecular building blocks with predetermined ordered structures starting from the well-known MOF NOTT-101. New linkers were synthesized that have a T-shape, based on a triphenylene tetra-carboxylate strut, and their incorporation into Cu(II)-based MOFs was investigated. The single-crystal structures of three new MOFs, UWCM-12 (fof), beta-UWCM-13 (loz), UWCM-14 (lil), with naked T-shaped linkers were determined; beta-UWCM-13 is the first reported example of the loz topology. A fourth MOF, UWDM-14 (lil) is analogous to UWCM-14 (lil) but contains a [2]rotaxane linker. Variable-temperature, H-2 solid-state NMR was used to probe the dynamics of a 24-membered macrocycle threaded onto the MOF skeleton.

Automated summary

The study explores the concept of robust dynamics by incorporating mechanically interlocked molecules into metal-organic framework materials, allowing large amplitude motions. New T-shaped linkers were designed and synthesized to create various MOFs with specific structures, demonstrating the potential for creating MOFs with diverse functions and dynamics.