Study on a set of bis-cyclometalated Ir(iii) complexes with a common ancillary ligand
作者:Younghun Byun、Woo Sung Jeon、Tae-Woo Lee、Yi-Yeol Lyu、Seok Chang、Ohyun Kwon、Eunsil Han、Heekyung Kim、Myeongsuk Kim、Ha-Jin Lee、Rupasree Ragini Das
DOI:10.1039/b719205c
日期:——
Bis-cyclometalated iridium(III) complexes [Ir(F2ppy)2ZN] (FZN), [Ir(F2CNppy)2ZN] (FCZN), [Ir(DMAF2ppy)2ZN] (FDZN) and [Ir(MeOF2ppy)2ZN] (MeOFZN) (F2ppy = 4′,6′-difluoro-2-phenylpyridinate, F2CNppy = 5′-cyano-4′,6′-difluoro-2-phenylpyridinate, DMAF2ppy = 4′,6′-difluoro-4-dimethylamino-2-phenylpyridinate, MeOF2ppy = 4′,6′-difluoro-4-methyl-2-phenylpyridinate and ZN = 3,5-dimethylpyrazole-N-carboxamide) emitting in the sky blue region were synthesized. We studied the effect of the ancillary ligand ZN and the substituents on the cyclometalating ligands on the crystal structures, photophysical and electrochemical properties and the frontier orbitals. Density functional theory (DFT) calculation results indicate that in FCZN and FDZN the cyclometalating ligands show negligible participation in the HOMO, the ancillary ligand ZN being the main participant along with the Ir(III) d-orbitals. MeOFZN exhibits the maximum photoluminescence quantum efficiency and radiative emission rates along with the dominant low frequency metal–ligand vibrations and maximum reorganization energy in the excited state. All the substituted complexes show more polar characteristics than FZN, FCZN possessing the highest dipole moment among the complexes. The performances of the solution-synthesised organic light emitting devices (OLEDs) of FZN, FCZN and FDZN doped in a blend of mCP (m-bis(N-carbazolylbenzene)) and polystyrene are studied.
双环金属化铱(III)配合物[Ir(F2ppy)2ZN](FZN)、[Ir(F2CNppy)2ZN](FCZN)、[Ir(DMAF2ppy)2ZN](FDZN)和[Ir(MeOF2ppy)2ZN](MeOFZN)(F2ppy = 4′,6′-二氟-2-苯基吡啶甲酸盐,F2CNppy = 5′-氰基-4′、6′-二氟-2-苯基吡啶甲酸盐、DMAF2ppy = 4′,6′-二氟-4-二甲基氨基-2-苯基吡啶甲酸盐、MeOF2ppy = 4′,6′-二氟-4-甲基-2-苯基吡啶甲酸盐和 ZN = 3,5-二甲基吡唑-N-甲酰胺)合成了发射天蓝色区域的光。我们研究了辅助配体 ZN 和环金属配体上的取代基对晶体结构、光物理和电化学性质以及前沿轨道的影响。密度泛函理论(DFT)计算的结果表明,在 FCZN 和 FDZN 中,环甲基配体在 HOMO 中的参与可以忽略不计,辅助配体 ZN 和 Ir(III)d-轨道是主要的参与物。MeOFZN 具有最高的光致发光量子效率和辐射发射率,同时在激发态具有主要的低频金属配体振动和最大的重组能。与 FZN 相比,所有取代复合物都显示出更强的极性,其中 FCZN 复合物的偶极矩最大。研究了掺杂在 mCP(间双(N-咔唑苯))和聚苯乙烯混合物中的 FZN、FCZN 和 FDZN 的溶液合成有机发光器件(OLED)的性能。