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 (CO2) as a sustainable C1 feedstock for the synthesis of value-added chemicals represents a promising strategy for mitigating rising atmospheric CO2 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 CO2 into 2-oxazolidinones. This material exhibited decent physiochemical stability and high surface area. The well-defined porous architecture facilitates enhanced CO2 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 CO2 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 CO2 utilization and provides a sustainable platform for the synthesis of industrially relevant heterocycles under mild conditions.