Luminescent pincer platinum(II) complexes with emission quantum yields up to almost unity: Photophysics, photoreductive c-c bond formation, and materials applications

Abstract

Luminescent pincer-type PtII complexes supported by C-deprotonated p-extended tridentate R-NN-R' ligands and pentafluorophenylacetylide ligands show emission quantum yields up to almost unity. Femtosecond time-resolved fluorescence measurements and time-dependent DFT calculations together reveal the dependence of excited-state structural distortions of [Pt(R-NN-R′)(CΞC-C6F5)] on the positional isomers of the tridentate ligand. Pt complexes [Pt(R-NN-R′)(CΞC-Ar)] are efficient photocatalysts for visible-light-induced reductive C-C bond formation. The [Pt(R-NN-R′)(C-C-C6F5)] complexes perform strongly as phosphorescent dopants for green- and red-emitting organic light-emitting diodes (OLEDs) with external quantum efficiency values over 22.1%. These complexes are also applied in two-photon cellular imaging when incorporated into mesoporous silica nanoparticles (MSNs).