Structure-Oriented {Y ₂ }-Lamellar MOF with Multisite Lewis/Brønsted Cooperativity for Efficient CO ₂ Cycloaddition and Tandem Deacetalization–Knoevenagel Reactions

Converting chemically inert and thermodynamically stable CO2 into value added products remains a fundamental challenge associated with carbon neutrality and long-term energy security. In this work, we present a chemically resilient nanoporous framework, {[Y(HPPDDC)(DMF)2]·3DMF·4H2O}n (NUC-190), constructed through the self-assembly of a deliberately engineered, structure-oriented linker, 4,4′-(4-phenylpyridine-2,6-diyl)diisophthalic acid (H4PPDDC). Cooperative organization between dinuclear [Y2(COO)6] clusters and the organic building unit gives rise to a two-dimensional layered motif, [Y(HPPDDC)]n, that contains extended in plane nanoscopic void regions with dimensions of 9.93 × 16.93 Å2. These layers are further integrated into a three-dimensional architecture through interlayer hydrogen bonding, generating nanocage-like cavities of 9.93 × 16.93 × 14.73 Å3. Remarkably, each {Y2} node binds four solvent molecules, an uncommon coordination environment that, upon activation, endows NUC-190a with pronounced Lewis acidic character. At the same time, spatially distributed carboxylate groups and electron-donating pyridyl moieties located on both sides of the lamellar surface impart intrinsic Lewis acid–base bifunctionality. Catalytic studies substantiate this structural design, as a bicomponent system composed of 0.12 mol % NUC-190a and 2.5 mol % n-Bu4NBr efficiently drives the cycloaddition of epoxides with carbon dioxide to form cyclic carbonates at 100 °C under 1.0 MPa CO2. NUC-190a also exhibits high efficiency in deacetalization Knoevenagel condensation reactions. Across both catalytic processes, the material demonstrates true heterogeneous behavior, excellent reusability, and wide substrate adaptability. Compared with our previously reported three-dimensional nanoporous MPFs, this work establishes a concise and broadly applicable strategy for constructing two-dimensional frameworks from H4PPDDC derived, structure oriented ligands, enabling the programmable incorporation of functional groups to access metal organic architectures with tunable properties.