Pd-nanoparticles supported onto functionalized poly(lactic acid)-based stereocomplexes for partial alkyne hydrogenation

Bipyridine-functionalized poly(lactic acid) (PLA)-based stereocomplexes were employed to stabilize Pd-nanoparticles (NPs). The well defined heterogeneous catalysts were suitable to catalyze the partial hydrogenation reaction (i.e. p(H2) = 3 bar, 25 and 60 °C) of phenylacetylene and diphenylacetylene in THF to give styrene and cis-stilbene with a chemoselectivity of 96% and 91%, respectively. Since the polymer support revealed stable under real catalytic conditions, stabilizing also efficiently the Pd-NPs in the course of the catalytic reaction, the heterogeneous catalytic system was easily recyclable. The catalytic activity as well as the chemoselectivity of the supported catalyst proved to be comparable in four consecutive catalytic cycles even by recovering the catalyst in air atmosphere after each cycle.