A Family of Ir-III Complexes with High Nonlinear Optical Response and Their Potential Use in Light-Emitting Devices

We synthesized a new family of Ir-III complexes [Ir(R-1-ppy)(2)(R-2-ppl)](PF6), where R-1-ppy = 2-phenylpyridine (ppy) or 2,4-difluorophenylpyridine (F-2-ppy) and R-2-ppl = pyrazino[2,3-f][1,10]phenanthroline (ppl) or 2,3-diethoxycarbonylpyrazino [2,3-f][1,10]phenanthroline (deeppl). The complexes were experimentally and theoretically characterized, noting the importance of the R-1 substituent on the modulation of HOMO level and its impact on the electronic properties. These compounds exhibit high second-order nonlinear optics (NLO) activity, especially, those with F-2-ppy ligands; this substituent modulates the charge transfer, optimizing the NLO response. The compounds also show blueshifted emissions, both in solution and as a solid film, which is desirable for use in light-emitting devices. This is the first use of the synthesized complexes for application in the two tasks.