In Co-catalyzed hydroformylation, where substantial phosphine rearrangement is required to stabilize the precatalyst and structures along the catalytic cycle, MOF-heterogenized phosphines reproduce homogeneous performance while offering recyclability and minimizing leaching (< 0.7 ppm Co).

We show via solid-state NMR studies that the phosphine ligands enjoy a high degree of mobility within the super-cages, which permits them to furnish mechanistically homogeneous and functionally heterogeneous transition-metal catalysts.

Our mechanistic proposal rationalizes why MOF-supported Rh(II) porphyrins are thermal hydrofunctionalization catalysts while molecular analogues prove unreactive. It also showcases the cooperation that can be achieved within a MOF matrix which precisely arranges Rh(II) centers in 3D space.

Via EPR and NMR spectroscopic analyses, kinetics, isotope labeling, IR spectroscopy, molecular model systems, radical trapping, digestion studies, quantum chemistry and molecular dynamics, we could get a rare level of insight into the mechanistic details of a heterogeneously catalyzed reaction.