Luminescent Pincer Platinum(II) Complexes with Emission Quantum Yields up to Almost Unity: Photophysics, Photoreductive CC Bond Formation, and Materials Applications

Abstract

Abstract Luminescent pincer‐type Pt II complexes supported by C‐deprotonated π‐extended tridentate RC^N^N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C^N^NR′)(CC‐C 6 F 5 )] on the positional isomers of the tridentate ligand. Pt complexes [Pt(R‐C^N^NR′)(CC‐Ar)] are efficient photocatalysts for visible‐light‐induced reductive CC bond formation. The [Pt(R‐C^N^NR′)(CC‐C 6 F 5 )] 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).