A Copper Nanoparticles-Anchored Hafnium Metal–Organic Framework Catalyst for Chemical Fixation of CO ₂ via Cyclization of Propargylic Amines

The utilization of carbon dioxide (CO 2 ) as a sustainable C1 feedstock for the synthesis of value-added chemicals represents a promising strategy for mitigating rising atmospheric CO 2 levels. Herein, we developed an efficient heterogeneous catalyst based on a non-noble metal nanoparticles (copper nanoparticles)-anchored, porous Hf(IV) metal–organic framework (MOF) ( Cu-NPs@1′ ) for the chemical fixation of CO 2 into 2-oxazolidinones. This material exhibited decent physiochemical stability and high surface area. The well-defined porous architecture facilitates enhanced CO 2 adsorption and efficient mass transport. The uniformly dispersed Cu nanoparticles provide accessible active sites for the cyclization of propargylic amines under mild conditions. Under optimized reaction conditions, the Cu-NPs@1′ catalyst delivers excellent yields (up to 91%) at atmospheric CO 2 pressure. Control experiments confirm the synergistic interplay between the porous Hf-MOF scaffold, and Cu-active sites play a crucial role for the observed catalytic performance. The catalyst exhibits broad substrate scope, tolerating diverse functional groups and affording the corresponding oxazolidinones in good yields (73–95%). Furthermore, Cu-NPs@1′ demonstrates good recyclability and structural stability over multiple catalytic cycles, as confirmed by PXRD, ATR-IR, and FE-SEM analyses. This work highlights the design of a stable, earth-abundant metal nanoparticle-based MOF catalyst for efficient CO 2 utilization and provides a sustainable platform for the synthesis of industrially relevant heterocycles under mild conditions.