Shortening the intramolecular Pd–Pd distances for photoactive dinuclear Pd( ii ) complexes

A series of dinuclear double-decker Pd(II) complexes exhibiting short Pd-Pd distances (ca. 2.78 Å) and red photoluminescence (λ_em = 600-625 nm in films) are described. Density functional theory calculations reveal the mixed ligand-to-ligand charge transfer/metal-metal-to-ligand charge transfer character of the excited state. Red OLEDs using these emitters have been demonstrated.