Pd-containing UiO-66-NH2 catalysts in organic synthesis

Catalysis is central to efficient organic synthesis, yet homogeneous catalysts often suffer from difficult recovery, limited recyclability, and metal contamination. Metal–organic frameworks (MOFs) offer porous, structurally tunable supports that combine accessible active sites with heterogeneous recovery. UiO-66-NH 2 is particularly attractive because of its stable Zr 6 -based framework, adjustable porosity, and modifiable amino groups. Functionalization with Schiff bases, amides, ionic liquids, nitrogen-rich ligands, polymers, and core–shell architectures enables control over palladium (Pd) coordination, dispersion, and accessibility while potentially suppressing its aggregation and leaching. This review critically examines Pd-containing UiO-66-NH 2 catalysts used in Suzuki–Miyaura, Mizoroki–Heck, Sonogashira, C O and multicomponent couplings, cyanation, carbonylative annulation, CO 2 fixation, reduction, and reductive amination. Reported systems are compared in terms of preparation, Pd characteristics, porosity, substrate scope, catalytic loading, activity, recyclability, and leaching. Collectively, the surveyed studies show that catalytic performance does not correlate with BET surface area alone; it is primarily governed by the accessibility, dispersion, and chemical state of Pd, together with framework defects, modifier functionality, and mass transfer. Future studies should adopt standardized catalytic comparisons, operando identification of active Pd species, complete metal-balance analysis, greener preparation, and validation under continuous-flow and scalable conditions.