Coordinative‐Guest‐Triggered Dimensional Crossover in a Metal–Organic Framework With Rigid Metal–Oxo Rods

ABSTRACT Structural phase transitions of metal–organic frameworks (MOFs) induced by guest‐molecule exchange within their pores have attracted considerable attention not only from the viewpoint of structural chemistry but also for the modulation of their functional properties. Herein, we report a reversible structural phase transition triggered by the exchange of coordinative guest molecules in a Pb‐based MOF composed of Pb 2+ ions and 2,5‐dihydroxy‐1,4‐benzoquinone (H 2 DHBQ), formulated as Pb(DHBQ)(DMF)(H 2 O) (DMF = N , N ‐dimethylformamide). This compound forms a 3D framework structure in which 1D Pb–O rods, constructed from Pb 2+ ions and oxygen atoms of bridging DHBQ 2− ligands, serve as secondary building units (SBUs). The framework contains 1D pores accommodating coordinative DMF and H 2 O molecules. Exchange of these guest molecules induces a reversible structural phase transition accompanied by significant changes in both the Pb–O rod structure and the overall dimensionality of the framework. To the best of our knowledge, this represents the first example of a MOF composed of rigid SBUs that exhibits a reversible structural phase transition involving a change in framework dimensionality driven by guest‐molecule exchange. These findings provide new insight into dynamic structural transformations in MOFs and highlight a strategy for controlling framework topology and properties through guest coordination.