Synthesis and dynamic behaviour of zwitterionic [M(η(6)-C6H5-BPh3)(coe)2] (M = Rh, Ir) cyclooctene complexes.

The synthesis and structural characterization of zwitterionic [(η(6)-C6H5-BPh3)M(coe)2] (M = Rh, Ir) cyclooctene complexes is described. Both complexes exhibit an unusual exo-endo conformation of both cyclooctene ligands in the solid state. However, an equilibrium between the endo-endo and exo-endo rotational isomers arising from the hindered rotation about the metal-cyclooctene bond is observed in solution.