Blue‐Light‐Emitting Complexes: Cationic (2‐Phenylpyridinato)iridium(III) Complexes with Strong‐Field Ancillary Ligands

The emission λmax are strikingly shorter (451, 482 nm) for the cationic dicarbonyl complex [Ir(ppy)2(CO)2]+ (2a) than those (473, 495 nm) of the anionic dicyano complex [Ir(ppy)2(CN)2]–, where CO and CN– are both sp carbon coordinating ligands and known to be strong‐field ligands showing a high trans effect. Sky‐blue‐light emission (λmax = 441–443 and 470–471 nm) could be obtained by modifying the ppy ligand to F2Meppy (2,4‐difluoro‐2‐phenyl‐m‐methylpyridinato anion) to prepare [Ir(F2Meppy)2LL′]+ [LL′ = (CO)2 (2aF2Me), (PPh2Me)2 (2bF2Me)]. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)