Development of Porous Cobalt-/Copper-Doped Carbon Nanohybrids Derived from Functionalized MOFs as Efficient Catalysts for the Ullmann Cross-Coupling Reaction: Insights into the Active Centers.

Newly emerging poly-functional metal-organic frameworks (MOFs) have been proved to be a promising alternative method for the hard/soft template to generate different carbon-based heterostructures. Herein, we have synthesized a sulfonyl-amide-based MOF (TMU-81) with an exceptionally high concentration of functional groups, which can interact strongly with metal ions and utilized it as a double-template platform to fabricate versatile catalysts by remaining structural regularity. The preloaded copper ions resided in pores of TMU-81 not only play a significant role in pore-forming by in situ renovating into Cu nanoparticles via the pyrolysis process but also trigger the morphological transformations of the resultant metal/carbon hybrids. The morphology of the TMU-81 was tuned from truncated octahedron to cubic in cobalt-/copper-doped carbon nanohybrids (MC-81), and also the Brunauer-Emmett-Teller surface area increased significantly up to 1450 cm/g. Benchmarks have been established for the performance of TMU-81, pyrolyzed TMU-81 (P-TMU-81), and MC-81s, as efficient and robust catalysts for the C-N cross-coupling reaction with aryl-halides and amines. The obtained MC-81 showed superior performance compared with pristine TMU-81 and pyrolyzed P-TMU-81. The catalysis performance is found to be closely dependent on the amount of preloaded Cu ions in the MOFs. After 5 cycles, the catalysts were reusable without any significant loss of activity. Benefiting from the structural and compositional advantages, the present approach offers an intelligent way to synthesis and design of structurally complex MOF hybrid and derived functionalized systems.