A novel, doubly functionalized, tris‐cylometallated iridium complex ( 2 ) was synthesized and investigated. The target complex was prepared by the bromination of a parent structure Ir(ppy) 2 fppy ( 1 ) containing two unsubstituted 2‐phenylpyridine ligands and one formyl substituted 2‐phenylpyridine ligand. Selective introduction of the bromine atoms onto the unsubstituted 2‐phenylpyridine ligands was achieved in para position relative to the cyclometallated carbon. The introduction of these substituents resulted in the modification of the photophysical and electrochemical properties in complex 2 in comparison to the starting complex 1 . DFT calculations indicate that the change in these properties is since the bromine substituents stabilize the HOMO orbital of complex 2 to a greater extent than the LUMO orbital, in comparison to complex 1 . The possibility of complex 2 being used as a building block for more functionalized iridium complexes was demonstrated through a combination of palladium catalyzed Suzuki‐Miyaura cross‐coupling and reductive amination reactions.
Sansee et al. (Sat,) studied this question.