Robust and Porous β‑Diketiminate-Functionalized Metal–Organic Frameworks for Earth-Abundant-Metal-Catalyzed C–H Amination and Hydrogenation

We
have designed a strategy for postsynthesis installation of the
β-diketiminate (NacNac) functionality in a metal–organic
framework (MOF) of UiO-topology. Metalation of the NacNac-MOF (I) with earth-abundant metal salts afforded the desired MOF-supported
NacNac-M complexes (M = Fe, Cu, and Co) with coordination environments
established by detailed EXAFS studies. The NacNac-Fe-MOF catalyst, I•Fe­(Me), efficiently catalyzed the challenging intramolecular
sp3 C–H amination of a series of alkyl azides to
afford α-substituted pyrrolidines. The NacNac-Cu-MOF catalyst, I•Cu­(THF), was effective in promoting the intermolecular
sp3 C–H amination of cyclohexene using unprotected
anilines to provide access to secondary amines in excellent selectivity.
Finally, the NacNac-Co-MOF catalyst, I•Co­(H),
was used to catalyze alkene hydrogenation with turnover numbers (TONs)
as high as 700 000. All of the NacNac-M-MOF catalysts were
more effective than their analogous homogeneous catalysts and could
be recycled and reused without a noticeable decrease in yield. The
NacNac-MOFs thus provide a novel platform for engineering recyclable
earth-abundant-element-based single-site solid catalysts for many
important organic transformations.