In-Core N4-Coordination of Palladium(II) in Dinaphthoporphycene: Synthesis, Structure, and Photophysical Studies

Dinaphthoporphycene (DNP) has emerged as a versatile ligand undergoing large out-of-plane distortion to form a cis-bimetallic complex with Pd­(II) using Pd­(OAc)₂ and out-of-plane monometallic complexes with Pd­(acac)₂ and PtCl₂(PhCN)₂. Herein, we are finally able to synthesize the in-core complex with Pd­(II) using PdCl₂(PhCN)₂ or PdCl₂. The crystal structure shows the palladium ion resides slightly above the N4-core, with the Pd­(II) dimensionally dissenting with the typical square planarity displayed by the reported in-core DNP complexes with Ni­(II) and Cu­(II) ions. The deformed complex displays a blue shift in the absorption spectra compared to DNP and its metallo-derivatives. PdDNP exhibits a moderate singlet oxygen generation ability (18%).