Selective hydroborative reduction of isocyanate using recyclable Ni-based metal–organic framework catalysts

Abstract

Selective reduction of isocyanate to formamide via hydroboration is highly challenging since isocyanate is prone to be converted into methylamine owing to the relatively low energy barrier of most catalysts. Metal–organic frameworks (MOFs), benefiting from their stable molecular architecture, tunable nodes and ligands, and modifiable functional groups, have been widely employed as heterogeneous catalysts in organic synthesis. Herein, Ni-MOF-74 frameworks were decorated with amino groups through the solvothermal method. After optimization of amino contents, the as-prepared NH₂-Ni-MOF-74-II catalyst demonstrated high catalytic activity under solvent-free conditions and superior selectivity with isocyanate and HBpin at different ratios. Moreover, a decent reusability of NH₂-Ni-MOF-74-II was verified with a conversion retention of more than 90% after seven catalytic cycles. This work suggests the great potential of selective organic catalysis by leveraging the synergistic effects of metallic nodes and grafted groups in MOFs.