Palladium, Corrole and Sapphyrin.

Palladium complexes of corrole and sapphyrin were prepared in high yield and fully characterized. The corrole provides a tetradentate/trianionic square planar coordination sphere for Pd(II), charge balanced by pyridinium. Both one and two Pd(II) ions may be accommodated by the pentapyrrolic skeleton of the sapphyrin and in each case the macrocycle acts as bidentate/monoanionic ligand and the inner-sphere square planar geometry is completed by allyl anions coordinated in an eta-3 fashion. NMR spectroscopy and X-ray crystallography data analysis uncovered the presence of interesting stereoisomers due to the flexibility of the ally ligands and also the pyrrole ring(s) that is/are not involved in metal binding.