Rational design of ligand-immobilized Rh/IRMOFs catalysts for 1-butene hydroformylation with high regioselectivity

Abstract

The diverse pore structures and excellent tunable proprieties of IRMOFs materials made the possibility to explore the effect of the mode of ligand-immobilization on its catalytic performance for 1-butene hydroformylation. In this work, we report a successful case of theory-guided rational design of a highly active ligand-immobilized Rh/IRMOF catalyst based on previous work. Density functional theory calculations of elementary reaction barriers for 1-butene hydroformylation over 1Rh/IRMOFs-PPh₃ models (IRMOF-1, -8, -10, -14, and -16) were performed. The calculation results and topographic steric maps analysis predicted that 1Rh/IRMOF-10-PPh₃ have superior catalytic performance. This can be attributed to the “shape-selective” effect of phosphine ligands grafted in the backbone on the reactive transition state. In addition, the anchoring positions of the phenyl phosphine ligand grafting on the skeleton of 1Rh/IRMOF-10-PPh₃ was identified in details. The 1Rh/IRMOF-10-PPh₃[3‐3] was predicted to have the highest n/i ratio. In order to verify the theoretical prediction, 1Rh/IRMOF-10–32PPh₃ catalyst was prepared by post-synthesis strategy and the n/i ratio was experimentally confirmed to be 3.49, which outperform the previous 1Rh/MOF-5-PPh₃ catalyst. This work suggests that the 1Rh/IRMOF-10-PPh₃ catalyst can be a promising catalyst for hydroformylation reactions.