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Abstract Compared to exploratory development of new structure types, pushing the limits of isoreticular synthesis on a high‐performance MOF platform may have higher probability of achieving targeted properties. Multi‐modular MOF platforms could offer even more opportunities by expanding the scope of isoreticular chemistry. However, navigating isoreticular chemistry towards best properties on a multi‐modular platform is challenging due to multiple interconnected pathways. Here on the multi‐modular pacs (partitioned acs) platform, we demonstrate accessibility to a new regime of pore geometry using two independently adjustable modules (framework‐forming module 1 and pore‐partitioning module 2). A series of new pacs materials have been made. Benzene/cyclohexane selectivity is tuned, progressively, from 4.5 to 15.6 to 195.4 and to 482.5 by pushing the boundary of the pacs platform towards the smallest modules known so far. The exceptional stability of these materials in retaining both porosity and single crystallinity enables single‐crystal diffraction studies of different crystal forms (as‐synthesized, activated, guest‐loaded) that help reveal the mechanistic aspects of adsorption in pacs materials. 

Abstract Isoreticular chemistry, which enables property optimization by changing compositions without changing topology, is a powerful synthetic strategy. One of the biggest challenges facing isoreticular chemistry is to extend it to ligands with strongly coordinating substituent groups such as unbound −COOH, because competitive interactions between such groups and metal ions can derail isoreticular chemistry. It is even more challenging to have an isoreticular series of carboxyl‐functionalized MOFs capable of encompassing chemically disparate metal ions. Here, with the simultaneous introduction of carboxyl functionalization and pore space partition, a family of carboxyl‐functionalized materials is developed in diverse compositions from homometallic Cr³⁺and Ni²⁺to heterometallic Co²⁺/V³⁺, Ni²⁺/V³⁺, Co²⁺/In³⁺, Co²⁺/Ni²⁺. Cr‐MOFs remain highly crystalline in boiling water. Unprecedentedly, one Cr‐MOF can withstand the treatment cycle with 10mNaOH and 12mHCl, allowing reversible inter‐conversion between unbound −COOH acid form and −COO⁻base form. These materials exhibit excellent sorption properties such as high uptake capacity for CO₂(100.2 cm³ g⁻¹) and hydrocarbon gases (e.g., 142.1 cm³ g⁻¹for C₂H₂, 110.5 cm³ g⁻¹for C₂H₄) at 1 bar and 298K, high benzene/cyclohexane selectivity (up to ≈40), and promising separation performance for gas mixtures such as C₂H₂/CO₂and C₂H₂/C₂H₄. 

Abstract Currently, few porous vanadium metal‐organic frameworks (V‐MOFs) are known and even fewer are obtainable as single crystals, resulting in limited information on their structures and properties. Here this work demonstrates remarkable promise of V‐MOFs by presenting an extensible family of V‐MOFs with tailorable pore geometry and properties. The synthesis leverages inter‐modular synergy on a tri‐modular pore‐partitioned platform. New V‐MOFs show a broad range of structural features and sorption properties suitable for gas storage and separation applications for C₂H₂/CO₂, C₂H₆/C₂H₄, and C₃H₈/C₃H₆. Thec/aratio of the hexagonal cell, a measure of pore shape, is tunable from 0.612 to 1.258. Other tunable properties include pore size from 5.0 to 10.9 Å and surface area from 820 to 2964 m²g⁻¹. With C₂H₂/CO₂selectivity from 3.3 to 11 and high uptake capacity for C₂H₂from 65.2 to 182 cm³g⁻¹(298K, 1 bar), an efficient separation is confirmed by breakthrough experiments. The near‐record high uptake for C₂H₆(166.8 cm³g⁻¹) contributes to the promise for C₂H₆‐selective separation of C₂H₆/C₂H₄. The multi‐module pore expansion enables transition from C₃H₆‐selective to more desirable C₃H₈‐selective separation with extraordinarily high C₃H₈uptake (254.9 cm³g⁻¹) and high separation potential (1.25 mmol g⁻¹) for C₃H₈/C₃H₆(50:50 v/v) mixture.