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

Luminescent pincer‐type PtII 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‐C6F5)] 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‐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). Multipurpose platinum: A phosphorescent PtII complex 1 with an emission quantum yield of 0.99 is employed as a catalyst for visible‐light‐induced reductive CC bond formation and as a dopant in organic light‐emitting diodes with an external quantum efficiency of 22.8 %. Encapsulating 1 in mesoporous SiO2 for two‐photon‐excited cellular imaging has been demonstrated.