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

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.