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The quest for understanding the structure-property correlation in porous materials has remained a persistent focus across various research domains, particularly within the sorption realm. Molecular metal oxide clusters, owing to their precisely tunable atomic structures and long-range order, exhibit significant potential as versatile platforms for sorption investigations. This study presents a series of isostructural Ti8Ce2-oxo clusters with subtle variations in coordinated linkers and explores their gas sorption behavior. Notably, Ti8Ce2-BA (where BA denotes benzoic acid) manifests a distinctive twostep profile during CO2 adsorption, accompanied by a hysteresis loop. This observation marks a pioneering instance within the metal oxide cluster field. Of particular intrigue, the presence of unsaturated Ce(Ⅳ) sites was found to be correlated with the stepped sorption property. Moreover, the introduction of an electrophilic fluorine atom, positioned ortho or para to the benzoic acid, facilitated precise control over gate pressure and stepped sorption quantities. Advanced in-situ techniques systematically unraveled the underlying mechanism behind this unique sorption behavior. The findings elucidate that robust Lewis base-acid interactions are established between CO2 molecules and Ce ions, consequently altering the conformation of coordinated linkers. Conversely, the F atoms primarily contribute to gate pressure variation by influencing the Lewis acidity of the Ce sites. This research advances the understanding in fabricating geometrically "flexible" metal-oxo clusters and provides profound insights into their host-guest interaction motifs. These insights hold substantial promise across diverse fields, particularly in CO2 gas capture and gas-phase catalysis, and offer valuable guidance for future adsorbent designs grounded in fundamental theories of structure-property relationships. 

Metal–organic frameworks (MOFs) containing open metal sites are advantageous for wide applications. Here, carboxylate linkers are replaced with triazolate coordination in pre-formed Zn-MOF-74 via solvent-assisted linker exchange (SALE) to prepare the novel NU-250, within the known hexagonal channel-based MAF-X25 series that has not previously been synthesized de novo .