Heteroleptic Ruthenium(II) Complex‐Containing Polymers and Their Bandgap Tuning and Photosensitizing Properties

A new synthetic route to novel ruthenium-containing polymers is reported. [Ru(L)(L')Cl(2)] type complexes (L and L' = bidentate N^N ligands) with a dibromo-substituted ligand were polymerized by Stille cross-coupling reaction. The subsequent displacement of chloride ligands by thiocyanate was highly effective and the structures of the target polymers were fully characterized. The main chain absorption showed a significantly red-shift upon metal coordination and the metal-to-ligand charge transfer (MLCT) band of the complex enhanced the photon harvesting ability of the polymer. The extent of π-electron delocalization of the ancillary ligands also showed interesting effects on the electronic properties of the polymers. The photosensitizing and bandgap tuning properties of these Ru(II) complexes demonstrated a new avenue to develop new classes of optoelectronic materials.