Sequentially Regulating the Structural Transformation of Copper Metal-Organic Frameworks (Cu-MOFs) for Controlling Site-Selective Reaction.

Abstract

Regulating atomically precise sites in catalysts to achieve site-selective reactions is remarkable but challenging. In this work, a convenient and facile solid-gas/liquid reaction strategy was used to construct controllable active sites in metal-organic frameworks (MOFs) to guide an orientation site-selective reaction. A flexible CuI-MOF-1 with dynamics originating from an anionic and tailorable framework could undergo a reversible structural transformation to engineer a topologically equivalent mixed-valent CuICuII-MOF-2 via a solid-gas/liquid oxidation/reduction process. More importantly, CuI-MOF-1 and CuICuII-MOF-2 could further execute the solid-gas/liquid reaction under ammonia vapor/solution to generate CuII-MOF-3. Furthermore, the transformation from CuI-MOF-1 to CuICuII-MOF-2 and CuII-MOF-3 served as controllable catalysts to facilitate site-selective reactions to realize direct C-N bond arylations. The results demonstrated that CuI-MOF-1 and CuII-MOF-3 possessed well-defined platforms with uniformly and accurately active sites to attain a "turn-on/off" process via different reaction routes, providing the desired site-selective ring-opening products.