New luminescent cyclometalated iridium(III) complexes containing fluorinated phenylisoquinoline-based ligands: Synthesis, structures, photophysical properties and DFT calculations

Abstract

Two new fluorinated phenylisoquinoline-based iridium(III) complexes, [Ir(f2piq)2(bipy)][PF6] (3a) and [Ir(fmpiq)2(bipy)][PF6] (3b) (f2piq = 1-(2,4-difluorophenyl)isoquinoline, fmpiq = 1-(4-fluoro-2-methylphenyl)isoquinoline, bipy = 2,2′-bipyridine), have been synthesized and fully characterized. Single crystal X-ray diffraction study has been undertaken on complexes 3a and 3b, which show that each adopts the distorted octahedral coordination geometry with the cis-C,C′ and trans-N,N′ configuration. The photoluminescence spectra of 3a and 3b exhibit yellow and orange emission maxima at 584 and 600 nm, respectively. The frontier molecular orbital diagrams and the lowest-energy electronic transitions of 3a–3b have been calculated with density functional theory (DFT) and time-dependent DFT (TD-DFT). The absorption and emission spectra of complex 3b is red-shifted relative to those of complex 3a, as a consequence of the nature of the methyl group.