Metal-metal d-d interaction through the discrete stacking of mononuclear M(II) complexes (M = Pt, Pd, and Cu) within an organic-pillared coordination cage.

Two molecules of planar MII(acac)2 complexes (M = Pt, Pd, and, Cu; acac = acetylacetonato) are efficiently stacked within an organic-pillared coordination cage, exhibiting characteristic spectroscopies (for M = Pt and Pd) and electron spin-spin coupling (for M = Cu) attributable to metal-metal interaction.