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

• Published in: Angewandte Chemie International Edition 2015-02, Vol.54 (7), p.2084-2089
• Main Authors: Chow, Pui-Keong, Cheng, Gang, Tong, Glenna So Ming, To, Wai-Pong, Kwong, Wai-Lun, Low, Kam-Hung, Kwok, Chi-Chung, Ma, Chensheng, Che, Chi-Ming
• Format: Article
• Language: English
• Subjects: Bonding; Cellular; density functional calculations; Dopants; Imaging; Ligands; luminescence; Organic light-emitting diodes; photochemistry; platinum; Quantum efficiency; Unity
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201408940

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.