Low-Valent Metals in Metal-Organic Frameworks Via Post-Synthetic Modification

Metal-organic frameworks (MOFs) provide uniquely tunable, periodic platforms for site-isolation of reactive low-valent metal complexes of relevance in modern catalysis, adsorptive applications, and fundamental structural studies. Strategies for integrating such species in MOFs include post-synthetic metalation, encapsulation and direct synthesis using low-valent organometallic complexes as building blocks. These approaches have each proven effective in enhancing catalytic activity, modulating product distributions (i.e., by improving catalytic selectivity), and providing valuable mechanistic insights. In this minireview, we explore these different strategies, as applied to isolate low-valent species within MOFs, with a particular focus on examples that leverage the unique crystallinity, permanent porosity and chemical mutability of MOFs to achieve deep structural insights that lead to new paradigms in the field of hybrid catalysis. Matrix isolation of low-valent complexes within metal-organic frameworks (MOFs) facilitates exceptional gas-phase catalytic activity, stabilization of solution-inaccessible catalysts, and fundamental insight into pertinent reaction mechanisms. MOFs present an ideal porous, crystalline, and chemically mutable matrix for such species. Herein we examine synthesis techniques and applications for the matrix isolation of low-valent complexes within MOFs.image