The synthesis and photophysics of tris-heteroleptic cyclometalated iridium complexes

Herein we report the synthesis and photophysical study of tris-heteroleptic complexes of the general formula IrLL′(acac), where L and L′ are two differently substituted 2-phenylpyridines (ppyH) and acacH is 2,4-pentanedione, using a combinatorial approach that could be employed for many ligand combinations. The tris-heteroleptic complexes and the analogous bis-heteroleptic complexes of the form IrL ₂(acac) have been studied by a combination of absorption and photoluminescence spectroscopies in conjunction with modelling by DFT and TD-DFT to elucidate the nature and location of the excited state in the novel species.