Rhodium complexes of 3,4-di(β-naphthyl)-2,5-diarylcyclopentadienone: indirect detection of slowed naphthyl rotation

In the solid state, [(acetylacetonate)-3,4-di(β-naphthyl)-2,5-diarylcyclopentadienone]rhodium(I) (4a, aryl=phenyl, 4b, aryl=m-xylyl) exist as head-to-tail dimers in which each rhodium is bonded to the γ-carbon of the acetylacetonate ligand in the other half of the molecule. These dimers are also favoured in solution at low temperature, and restricted naphthyl rotation results in the formation of numerous conformers whereby the naphthyls can …