Ligand effect in the Rh-NP catalysed partial hydrogenation of substituted arenes

The Rh nanoparticles Rh1-Rh4 stabilised by the mono- and bidentate phosphine and phosphite ligands I-IV were synthesised, characterised and applied as catalysts in the partial hydrogenation of substituted arenes. In the case of disubstituted arenes, selectivities for the corresponding cyclohexene derivatives of up to 39% were achieved at ca.40% conversion. The effect of parameters such as temperature and pressure was also examined. In the hydrogenation of styrene, very high selectivities for ethylbenzene were achieved with TOF values up to ca.23 500 h super(-1). All these results show that the catalytic performance of small Rh-NPs can be modulated by the appropriate choice of stabilising agents.