Metal-organic frameworks with Rod yttrium secondary building units | Poster Board #1103

We present the synthesis and characterization of a novel hydroxamate-based yttrium metal-organic framework (MOF), designated MOF-419 [Y(HCOO)(BDH)], featuring rod-shaped secondary building units (rod-SBUs). The compound was successfully synthesized through the chelating construction of benzene-1,4-hydroxamate linkers, with formic acid acting as a crucial modulator for the formation of rod-SBUs. It should be noted that current strategies for obtaining rod-MOFs remain limited, and our study highlights the unique binding behavior of the organic linker. We hypothesize that while the 5-member ring displays favorable chelation, the 4-member ring does not, which causes carboxylates to serve as bridging units rather than chelating units. Intriguingly, hydroxamate functions as both chelating and bridging units. We ascribe the formation of rod-SBUs to the precise combination of solely bridging (formate) units and chelating-bridging (hydroxamate) units. Notably, without formate, no MOF product was formed under identical conditions. The successful synthesis of rod MOF-419 introduces a new strategy involving a hydroxamate linker and modulator. Further characterization reveals that MOF-419 exhibits permanent porosity and a BET surface area of 1130 m²/g. Its hydrophobic pore environment and gas sorption properties were investigated through single-crystal X-ray diffraction and nitrogen, carbon dioxide, and water sorption experiments. Our findings contribute to the study and understanding of rod MOFs with chelating linkages, offering a foundation for future research in this area.