Phosphorescent Platinum(II) Complexes With Diazinedipyrrolide Pincer Ligands: Structure and Photophysical Properties

This study reports the design, synthesis, and photophysical investigation of a series of pyrimidinedipyrrolide platinum(II) complexes, including a pyrazine analog. The complexes exhibit square‐planar geometries and strong phosphorescence arising from metal‐to‐ligand charge transfer transitions, as confirmed by X‐ray crystallography and time dependent density functional theory (TD‐DFT) calculations, respectively. Systematic modification of the C6 substituent on the diazine core and the ancillary ligand enables fine‐tuning of the absorption and emission properties. All complexes are emissive in solution (Φ Em comprised between 0.02 and 0.24), with emission maxima spanning 485–592 nm and lifetimes characteristic of phosphorescence ( τ 0 ranging from 3.0 to 23.1 µs). Replacement of the pyrimidine core with a pyrazine unit induces a red‐shifted but weaker emission.