No abstract

No abstract

Electrophilic amination has emerged as a more environmentally benign approach to construct arene C−N bonds. However, heterogeneous catalysts remain largely unexplored in this area, even though their use could facilitate product purification and catalyst recovery. Here we investigate strategies to heterogenize a Cu(2,2′-bipyridine) catalyst for the amination of arenes lacking a directing group with hydroxylamine-O-sulfonic acid (HOSA). Besides immobilization of Cu on a metal−organic framework (MOF) or covalent organic framework (COF) with embedded 2,2′-bipyridines, a ship-in-a-bottle approach was followed in which the Cu complex is encapsulated in the pores of a zeolite. Recyclability and hot centrifugation tests show that zeolite Betaentrapped Cu II (2,2′-bipyridine) is superior in terms of stability. With N-methylmorpholine as a weakly coordinating, weak base, simple arenes, such as mesitylene, could be aminated with yields up to 59%, corresponding to a catalyst TON of 24. The zeolite could be used in three consecutive runs without a decrease in activity. Characterization of the catalyst by EPR and XAS showed that the active catalytic complex consisted of a site-isolated Cu II species with one 2,2′-bipyridine ligand.

Hydroisomerisation of n‐butane to isobutane is a challenging reaction, even for Pt‐loaded zeolites with strong acid sites. In comparison with 10‐membered ring (10MR) zeolites, 12‐membered ring (12MR) zeolites give consistently higher isomerisation yields. We report that besides the known catalysts with *BEA topology, also three‐dimensional frameworks with MSE and YFI topologies (with Si/Al∼10) are suitable to obtain high isobutane selectivities and yields. As an alternative to Beta zeolites obtained via templated synthesis, Beta zeolites prepared via a template‐free synthesis proved to be more active at lower temperatures and delivered higher isobutane yields in such conditions. Side reactions such as the Pt‐catalysed hydrogenolysis were successfully suppressed by decreasing the Pt content, even in hydrogen‐rich conditions. Isobutane yields up to 31 % were achieved in a single pass.