A series of tetradentate Pd(Ⅱ) and Pt(Ⅱ) complexes containing fused 5/6/6 metallocycles with phenyl N-heteroaromatic ben-zo[d]imidazole (pbiz),benzo[d]oxazole (pboz) or benzo[d]thiazole (pbthz)-containing ligands was developed.Systematic studies by experiments and theoretical calculations reveal that both the central metal and the benzannulated N-heteroaromatic ring have sig-nificant influence on the electrochemical,photophysical and excited-state properties of the Pd(Ⅱ) and Pt(Ⅱ) complexes.In identical condition,compared to pbiz-based Pd(Ⅱ) and Pt(Ⅱ) complexes,the corresponding metal complexes with pboz and pbthz-containing ligand show significant red-shift emission spectra.Pd(Ⅱ) complexes exhibit blue-shift emission spectra in comparison with the corre-sponding Pt(Ⅱ) complexes.The Pt(Ⅱ) complexes possess more metal-to-ligand charge transfer (3MLCT) character in their T1 states,which enables the Pt(Ⅱ) complexes to have much higher quantum efficiencies (ΦPL) and shorter excited-state lifetimes (τ),resulting in large radiative decay rates (kr).Especially,Pt(pbiz) has a ΦPL of 94％ with a τ of 4.0 μs in 5 wt％ doped PMMA film at room tempera-ture.Pt(pbiz)-doped green organic light-emitting diode (OLED) using 26mCPy as host demonstrated a peak external quantum effi-ciency (EQE) of 21.6％ and a maximum brightness (Lmax) of 55481 cd/m2,which still maintained an EQE of 16.5％ and 10.8％ at 1000 and 10000 cd/m2,respectively.

Guijie Li;Hua Guo;Xiaoli Fang;Yun-Fang Yang;Yulu Sun;Weiwei Lou;Qisheng Zhang;Yuanbin She

College of Chemical Engineering,Zhejiang University of Technology,Hangzhou,Zhejiang 310014,China;MOE Key Laboratory of Macromolecular Synthesis and Functionalization,Department of Polymer Science and Engineering,Zhejiang University,Hangzhou,Zhejiang 310027,China

中国化学（英文版）

[1]Guijie Li;Hua Guo;Xiaoli Fang;Yun-Fang Yang;Yulu Sun;Weiwei Lou;Qisheng Zhang;Yuanbin She-.Tuning the Excited State of Tetradentate Pd(Ⅱ) and Pt(Ⅱ)Complexes through Benzannulated N-Heteroaromatic Ring and Central Metal)[J].中国化学（英文版）,2022(02):223-234

Tetradentate,Benzannulated,Heteroaromatic,tetradentate,metallocycles,heteroaromatic,zo,pbiz,oxazole,pboz,pbthz,benzannulated,3MLCT,26mCPy

Tuning,Excited,State,Pd,Pt,Complexes,through,Ring,Central,Metal,series,complexes,containing,fused,phenyl,imidazole,benzo,thiazole,ligands,was,developed,Systematic,studies,by,experiments,theoretical,calculations,reveal,that,both,central,ring,have,influence,electrochemical,photophysical,excited,properties,In,identical,condition,compared,corresponding,show,significant,shift,emission,spectra,exhibit,blue,comparison,possess,more,charge,transfer,character,their,states,which,enables,much,higher,quantum,efficiencies,PL,shorter,lifetimes,resulting,large,radiative,decay,rates,kr,Especially,has,wt,doped,PMMA,film,room,tempera,ture,green,organic,light,emitting,diode,OLED,using,host,demonstrated,peak,external,ciency,EQE,maximum,brightness,Lmax,cd,still,maintained,respectively

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