Relative Influence of Pd(II) and Pt(II) Metal Centers on the Strength of Interactions Between Planar Species

Palladium(II) or platinum(II) are often incorporated into metallo-supramolecular architectures as their square-planar geometry and relative accessibility make them attractive targets. The square-planar cationic panels where palladium(II) or platinum(II) are bound within these species frequently participate in interactions which enable host-guest chemistry or controlled conformation. We here investigate whether there could be a difference between the strength of interactions established by Pd(II) or Pt(II)-containing species. Analogous Pd(II) and Pt(II) model complexes were synthesized, and their behavior compared against aromatic and platinate guests. Predominantly through ¹H NMR techniques, we have established that Pt(II) can allow for π interactions with an aromatic guest roughly twice the strength of their Pd(II) counterparts, where binding is strong. Similarly, the interactions between the Pt(II) model complex with a platinate guest, were stronger than those of the Pd(II) model complex, although notably weak in both cases.