• chelates;
  • density functional calculations;
  • donor–acceptor systems;
  • mixed-valent compounds;
  • N ligands


Electron delocalization of new mixed-valent (MV) systems with the aid of lateral metal chelation is reported. 2,2′-Bipyridine (bpy) derivatives with one or two appended di-p-anisylamino groups on the 5,5′-positions and a coordinated [Ru(bpy)2] (bpy=2,2′-bipyridine), [Re(CO)3Cl], or [Ir(ppy)2] (ppy=2-phenylpyridine) component were prepared. The single-crystal molecular structure of the bis-amine ligand without metal chelation is presented. The electronic properties of these complexes were studied and compared by electrochemical and spectroscopic techniques and DFT/TDDFT calculations. Compounds with two di-p-anisylamino groups were oxidized by a chemical or electrochemical method and monitored by near-infrared (NIR) absorption spectral changes. Marcus–Hush analysis of the resulting intervalence charge-transfer transitions indicated that electron coupling of these mixed-valent systems is enhanced by metal chelation and that the iridium complex has the largest coupling. TDDFT calculations were employed to interpret the NIR transitions of these MV systems.