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- ItemSelective cobalt nanoparticles for catalytic transfer hydrogenation of N-heteroarenes(Cambridge : RSC, 2017) Chen, Feng; Sahoo, Basudev; Kreyenschulte, Carsten; Lund, Henrik; Zeng, Min; He, Lin; Junge, Kathrin; Beller, MatthiasNitrogen modified cobalt catalysts supported on carbon were prepared by pyrolysis of the mixture generated from cobalt(ii) acetate in aqueous solution of melamine or waste melamine resins, which are widely used as industrial polymers. The obtained nanostructured materials catalyze the transfer hydrogenation of N-heteroarenes with formic acid in the absence of base. The optimal Co/Melamine-2@C-700 catalyst exhibits high activity and selectivity for the dehydrogenation of formic acid into molecular hydrogen and carbon dioxide and allows for the reduction of diverse N-heteroarenes including substrates featuring sensitive functional groups.
- ItemUltra-small cobalt nanoparticles from molecularly-defined Co-salen complexes for catalytic synthesis of amines(Cambridge : RSC, 2020) Senthamarai, Thirusangumurugan; Chandrashekhar, Vishwas G.; Gawande, Manoj B.; Kalevaru, Narayana V.; Zbořil, Radek; Kamer, Paul C.J.; Jagadeesh, Rajenahally V.; Beller, MatthiasWe report the synthesis of in situ generated cobalt nanoparticles from molecularly defined complexes as efficient and selective catalysts for reductive amination reactions. In the presence of ammonia and hydrogen, cobalt-salen complexes such as cobalt(ii)-N,N′-bis(salicylidene)-1,2-phenylenediamine produce ultra-small (2-4 nm) cobalt-nanoparticles embedded in a carbon-nitrogen framework. The resulting materials constitute stable, reusable and magnetically separable catalysts, which enable the synthesis of linear and branched benzylic, heterocyclic and aliphatic primary amines from carbonyl compounds and ammonia. The isolated nanoparticles also represent excellent catalysts for the synthesis of primary, secondary as well as tertiary amines including biologically relevant N-methyl amines. This journal is © The Royal Society of Chemistry.