Low valent palladium benzoquinone complexes bearing different spectator ligands. The versatile coordinative capability of benzoquinone

In the palladium(0) complexes benzoquinone can coordinate either η2 or η4 and the ensuing coordinative choice was easily inferred from the 1H and 13C NMR features. The benzoquinone hapticity is not easily predictable, although the η2 coordinative mode appears to be favored in the case of rigid spectator ligands.