Dinuclear platinum() complex dominated by a zig-zag-type cyclometalated ligand: a new approach to realize high-efficiency near infrared emission

• Published in: Journal of materials chemistry. C, Materials for optical and electronic devices Materials for optical and electronic devices, 2018, Vol.6 (21), p.5769-5777
• Main Authors: Yang, Shengyi, Meng, Fanyuan, Wu, Xiugang, Yin, Zheng, Liu, Xianzhi, You, Caifa, Wang, Yafei, Su, Shijian, Zhu, Weiguo
• Format: Article
• Language: English
• Subjects: Coordination compounds; Crystal structure; Efficiency; Electroluminescence; Emission; Ligands; Light emitting diodes; Near infrared radiation; Nitrogen; Photoluminescence; Platinum; Quantum efficiency; Single crystals
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/c8tc01142g

Two new zig-zag type di- and mono-nuclear platinum( ii ) complexes of (BuPh-BDIQ)Pt 2 (dpm) 2 and (BuPh-BDIQ)Ptdpm were synthesized and characterized by using a zig-zag type cyclometalating ligand 3,10-di( tert -butyl)-5,12-bis(4-( tert -butyl)phenyl)-benzodiisoquinoline (BuPh-BDIQ). Their single-crystal structures, and photophysical, electrochemical and electroluminescent properties were primarily investigated. Compared with (BuPh-BDIQ)Ptdpm, (BuPh-BDIQ)Pt 2 (dpm) 2 exhibited a significantly increased photoluminescent efficiency of 3.64% and a red-shifted near-infrared (NIR) emission peak at 718 nm owing to its enhanced rigid planar structure in a nitrogen atmosphere. As a result, only (BuPh-BDIQ)Pt 2 (dpm) 2 presented NIR electroluminescent emission in a doped polymeric light-emitting diode. The highest external quantum efficiency of 0.97% and a radiant intensity of 146 μW cm −2 were observed for the device at 2 wt% dopant concentration, which is higher than the values of previous NIR-emitting di-nuclear platinum complexes constructed with cyclometalated ligands. Furthermore, efficiency roll-off was efficiently inhibited. This indicates that high-efficiency NIR-emitting di-nuclear platinum complexes can be obtained by designing a zig-zag type C^N-C^N tetradentate cyclometalating ligand with a big rigid planar saw band. Two new zig-zag type di- and mono-nuclear platinum( ii ) complexes of (BuPh-BDIQ)Pt 2 (dpm) 2 and (BuPh-BDIQ)Ptdpm were synthesized and characterized by using a zig-zag type cyclometalating ligand BuPh-BDIQ.