Structural Engineering of a Zn ₄ O-Based Metal–Organic Framework via Geometric Deformation of Secondary Building Units for Enhanced Trace Benzene Adsorption

Conformation engineering of building units has shown great potential in metal-organic frameworks (MOFs), enabling the construction of novel architectures with distinct topologies and thereby enriching the structural diversity of MOFs. However, research associated with the geometrically deformable metal-containing units without altering connectivity remains scarce. Here, we report the synthesis of a new Zn₄O-based MOF, namely, WUST-4, with a 1,3,5-tris(4-carboxyphenyl)benzene (H₃BTB) linker. Although sharing similar building units like the isomer MOF-177, WUST-4 features an unprecedented topological net due to the different geometries of Zn₄O clusters and conformations of BTB linkers under controlled solvent conditions. Particularly, the Zn₄O cluster in WUST-4 exhibits a unique distorted trigonal prismatic geometry, which is seldomly observed in other Zn₄O-based MOFs. This geometric deformation arises from cooperative linker migration and solvent coordination, diverging from the conventional octahedral Zn₄O configuration. Owing to unique pore structures with narrow traps and coordinatively unsaturated Zn²⁺ sites along the channel walls, WUST-4 shows a higher benzene uptake at low pressure than MOF-177, suggesting its potential in the application of trace benzene removal.