Highly phosphorescent organopalladium(ii) complexes with metal–metal-to-ligand charge-transfer excited states in fluid solutions

Abstract

Dinuclear pincer-type cyclometalated Pd(II) complexes with foldable diacetylide ligands show crystallographically determined intramolecular Pd⋯Pd contacts of 3.203–3.380 Å. In deoxygenated fluid solutions, these Pd(II) complexes are highly phosphorescent in the red region with emission quantum yields up to 48%, which has been ascribed to metal–metal-to-ligand charge-transfer (MMLCT) excited states in nature.