Metal–organic frameworks (MOFs) are crystalline, porous materials composed of metal centers and organic linkers. They have applications, e.g., in gas separation or catalysis. MOFs used for catalysis can, for example, contain one metal for the formation of their porous structure and a second, catalytically active metal that is immobilized in the framework. The commonly used zeolitic imidazolate framework (ZIF-8), for example, is a zinc-based MOF that could be used to accommodate catalytically active metal species within its pores.

Arshad Aijaz, Rajiv Gandhi Institute of Petroleum Technology (RGIPT), Uttar Pradesh, India, Debasis Banerjee, Indian Institute of Technology Roorkee, Uttarakhand, India, and colleagues have developed a ZIF-type MOF that encapsulates nickel 1,10-phenanthroline complexes as the catalytically active species. The resulting MOF with immobilized nickel centers can be used as a recyclable heterogeneous catalyst for the oxidative dehydrogenation of N-heterocycles (general reaction pictured).

Using their new catalyst, the team synthesized a series of five- and six-membered fused N-heterocycles with one or two nitrogen atoms each (pictured; n = 0, 1; X = C, N) in mostly moderate to excellent yields. The method is suitable for the late-stage transformation of complex, drug-like molecules. The catalyst could be recycled up to four times without a drastic loss in catalytic activity.

• Reusable Ni-immobilized MOF Catalyst for Dehydrogenation of N-heterocycles Under Milder Conditions,
  Debasis Banerjee, Motahar Sk, Shadab Saifi, Sourajit Bera, Adrija Ghosh, Arshad Aijaz,
  Chem. Eur. J. 2024.
  https://doi.org/10.1002/chem.202404219