Bimetallic PdRh-Fe3O4 nanoparticle-catalyzed highly selective quinoline hydrogenation using ammonia borane

We report an efficient use of bimetallic PdRh alloy nanoparticles on Fe3O4 for chemoselective quinoline hydrogenation to 1,2,3,4-tetrahydroquinoline with ammonia borane as a convenient hydrogen source at room temperature. Introduction of palladium to rhodium in the catalyst design has enabled us to minimize poisoning effect by quinoline. When we varied the molar ratio of Pd to Rh, the catalyst with a Pd:Rh ratio of 0.23:1.0 showed the highest catalytic activity for quinoline reduction with > 99% yield. Additionally, using Fe3O4 as a support was uniquely advantageous because it allowed facile isolation of the catalyst from the solution with the aid of an external magnet for reuse of the catalyst up to 10 times. [Display omitted] •Selective hydrogenation of quinoline using PdRh alloy NPs supported on Fe3O4.•Effective alleviation of poisoning effect with the combination of two metals, Pd and Rh.•No high pressure and temperature needed for the hydrogenation with the use of ammonia borane.•Separation of PdRh NPs from the reaction mixture using an external magnet.