Synthesis and photophysical properties of cyclometalated heteroleptic iridium(III) complexes containing pyridyl/isoquinolyl-imino-isoindoline ancillary ligand

AbstractA new class of monoanionic N^N ligand, pyridyl/isoquinolyl-imine-isoindoline (L1 and L2), have been selected as ancillary ligands to form two novel neutral cyclometalated heteroleptic iridium complexes (Ir(III)(dfppy)2(LN^N)), in which dfppy is the cyclometalated ligand 2-(2′,4′-difluorophenyl)pyridine. Both complexes exhibit broad emission spectra at red-visible region. By fusion with benzene ring of the ancillary ligand, further bathochromic shift of the emission band to the deeper red region (centred at 665 nm in solid phase) can be achieved. An analysis of the structure-property relationship has been carried out based on single crystal X-ray crystallographic structures, optical spectroscopy and DFT theoretical calculations.