Synthesis and characterisation of two novel Rh(I) carbene complexes: Crystal structure of [Rh(acac)(CO)(L1)]

Two [Rh(acac)(CO)(L)] (L = carbene) complexes were prepared and evaluated as catalyst precursors in the hydroformylation of 1-hexene. In the presence of an added phosphine or phosphite ligand no added benefit is derived from the presence of the carbene ligand as compared to using [Rh(acac)(CO)2] as catalyst precursor. 31P NMR spectroscopy indicates liberation of the carbene under these conditions.