Design and Synthesis of Iridium Bis(carbene) Complexes for Efficient Blue Electrophosphorescence
Design and Synthesis of Iridium Bis(carbene) Complexes for Efficient Blue Electrophosphorescence
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DOI：
10.1002/chem.201100317
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发表时间：
2011-08-01
影响因子：
4.3
通讯作者：
Cheng, Chien-Hong
中科院分区：
文献类型：
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作者：
Hsieh, Cheng-Han;Wu, Fang-Iy;Cheng, Chien-Hong
五种铱双（卡宾）配合物，[Ir（pmi）（2）（pypz）]（1）、[Ir（mppmi）（2）（pypz）]（2）、[Ir（fpmi）（2）（pypz）]（3）、[Ir（fpmi）（2）（pyim）]（4）和[Ir（fpmi）（2）（tfpypz）]（5）（pmi=1-苯基-3-甲基咪唑啉-2-亚基-C，C-2 '; fpmi=1-（4-氟苯基）-3-甲基咪唑啉-2-亚基-C，C-2'; mppmi = 1-（4-氟苯基）-3-甲基咪唑啉-2-亚基-C，C-2 ';（4-甲基-苯基）-3-甲基咪唑啉-2-亚基-C，C2 '; pypz=2-（1H-吡唑-5-基）吡啶基; pyim=2-（1H-咪唑-2-基）吡啶;且tfpypz=2-（3-（三氟甲基）-1H-吡唑-5-基）吡啶），并通过核磁共振谱对其结构进行了表征，质谱和X射线衍射。这些配合物显示出磷光发射，最大发射波长在453和490 nm之间。各种分光光度测量，循环伏安研究和密度泛函理论（DFT）计算表明，与大多数磷光环化铱配合物不同，这些铱配合物的最低未占分子轨道（LUMO）能量和发射态主要由N，N '-杂芳族（N布尔AND N）配体控制。尽管这些配合物的LUMO能级主要在N布尔AND N配体上，但电致发光（EL）器件的效率非常高。例如，使用[Ir（mpmi）（2）（pypz）]、[Ir（fpmi）（2）（pypz）]和[Ir（fpmi）（2）（tfpypz）]作为掺杂剂发射体的EL器件表现出具有15.2、14.1和7.6%的外量子效率和15.2、14.1和7.6%的国际委员会（Commission Internationale d 'Enclairage）（x，y）坐标（CIEx，y）的浅蓝色至深蓝色电致磷光。（0.14，0.27）、（0.14，0.18）和（0.14，0.10）。
Five iridium bis(carbene) complexes, [Ir(pmi)(2)(pypz)] (1), [Ir(mpmi)(2)(pypz)] (2), [Ir(fpmi)(2)(pypz)] (3), [Ir(fpmi)(2)(pyim)] (4), and [Ir(fpmi)(2)(tfpypz)] (5) (pmi=1-phenyl-3-methylimdazolin-2-ylidene-C, C-2'; fpmi=1-(4-fluorophenyl)-3-methylimdazolin-2-ylidene-C,C-2'; mpmi=1-(4-methyl-phenyl)-3-methylimdazolin-2-ylidene-C, C2'; pypz=2-(1H-pyrazol-5-yl)pyridinato; pyim=2-(1H-imidazol-2-yl) pyridinato; and tfpypz=2-(3-(trifluoromethyl)-1H-pyrazol-5-yl)pyridinato), were synthesized and their structures were characterized by NMR spectroscopy, mass spectroscopy and X-ray diffraction. These complexes showed phosphorescent emission with the emission maxima between 453 and 490 nm. Various spectrophotometric measurements, cyclic voltammetric studies, and density functional theory (DFT) calculations show that, unlike most of the phosphorescent cyclometalated iridium complexes, the lowest unoccupied molecular orbital (LUMO) energy and the emissive state of these iridium complexes are mainly controlled by the N,N'-heteroaromatic (N boolean AND N) ligand. Despite the fact that the LUMO levels of these complexes are mainly on the N boolean AND N ligands, the efficiencies of the electroluminescent (EL) devices are very high. For example, the EL devices using [Ir(mpmi)(2)(pypz)], [Ir(fpmi)(2)( pypz)], and [Ir(fpmi)(2)(tfpypz)] as the dopant emitters exhibited light- to deep-blue electrophosphorescence with external quantum efficiencies of 15.2, 14.1, and 7.6% and Commission Internationale d'Enclairage (x, y) coordinates (CIEx,y) of (0.14, 0.27), (0.14, 0.18) and (0.14, 0.10), respectively.