Over the last decade, the hydrogenation of arenes catalysed by soluble nanoparticles has attracted much interest from both academic and industrial research groups due to the milder conditions and the interesting selectivities achieved when compared to those obtained with classical heterogeneous catalysts. When substituted arenes are used as substrates in this reaction, the stereoselectivity is a key objective, and high levels of enantioselectivity are yet to be achieved.

Well defined Ni nanoparticles stabilized with N-heterocyclic carbenes have been synthesized through decarboxylation of a zwitterionic CO₂ adduct and they selectively hydrogenate internal alkynes into (Z)-alkenes under mild reaction conditions.