Influence of the monodentate ancillary ligand on the photophysical properties of Pt(II) complexes bearing a symmetric dianionic tridentate luminophore

Abstract

Herein we present a study of the influence of the ancillary ligand on the photophysical properties of Pt(II) complexes with a symmetric tridentate luminophore. Starting from a previously used bulky triphenylphosphane (PPh3) as the monodentate ancillary ligand, progressively smaller ancillary ligands were introduced, namely a PPh2Me and a PPhMe2 and finally compared with a planar 4-amylpyridine. We observed that the emission wavelength of the monomer was not influenced by the monodentate ligand, and that excimer formation only occurs for the fully planar complex. Surprisingly, intermolecular deactivation pathways can be largely suppressed even with the smallest phosphane. This knowledge is important for the design and realization of triplet emitters for optoelectronic devices.