Diarylamino functionalized pyrene derivatives for use in blue OLEDs and complex formation
作者:Wen-Li Jia、Theresa McCormick、Qin-De Liu、Hiroshi Fukutani、Michael Motala、Rui-Yao Wang、Ye Tao、Suning Wang
DOI:10.1039/b410330k
日期:——
Three new 2,2′-dipyridylamino functionalized pyrene derivatives, 1-pyrenyl-2,2′-dipyridylamine (1), 4-(1-pyrenyl)phenyl-2,2′-dipyridylamine (2), and 4-[4′-(1-pyrenyl)biphenyl]-2,2′-dipyridylamine (3) have been synthesized and fully characterized. For comparison of electronic properties, a diphenylamino functionalized molecule 4-[4′-(1-pyrenyl)biphenyl]diphenylamine (4) has also been synthesized. Compounds 1–4 are bright blue emitters in solution and in the solid state with λmax at ∼420–460 nm and a high emission efficiency in solution. All four compounds form amorphous glasses with Tg values of 66 °C, 79 °C, 165 °C, and 98 °C, respectively. The electronic properties of the four compounds were examined by spectroscopic methods, cyclic voltammetry and Gaussian 98 molecular orbital calculations. The utilities of this class of molecules in OLEDs have been demonstrated by EL devices of compounds 3 and 4, which showed that 3 can function as a bright blue emitter and an electron transport material in a double-layer device while 4 can function as a bright blue emitter and a hole transport molecule in a triple-layer device. The dipyridylamino functional group in molecules 1–3 are capable of chelating to metal ions such as Zn(II) as demonstrated by the synthesis and structure of the complex [2·(Zn(O2CCF3)2]2
(5). The binding of Zn(II) ions to the dipyridyl group causes a reduction of the emission efficiency of the ligand 2.
我们合成了三种新的 2,2′-二吡啶氨基官能化芘衍生物:1-芘基-2,2′-二吡啶基胺(1)、4-(1-芘基)苯基-2,2′-二吡啶基胺(2)和 4-[4′-(1-芘基)联苯]-2,2′-二吡啶基胺(3),并对它们进行了全面表征。为了比较电子特性,还合成了二苯基氨基功能化分子 4-[4′-(1-芘基)联苯]二苯胺(4)。化合物 1-4 在溶液和固态中都是明亮的蓝色发光体,λmax 在 ∼420-460 纳米,在溶液中具有很高的发射效率。所有四种化合物都能形成无定形玻璃,其 Tg 值分别为 66 ℃、79 ℃、165 ℃ 和 98 ℃。通过光谱方法、循环伏安法和高斯 98 分子轨道计算,研究了这四种化合物的电子特性。化合物 3 和化合物 4 的电致发光器件证明了这一类分子在有机发光二极管中的实用性,结果表明,化合物 3 在双层器件中可作为亮蓝色发光体和电子传输材料,而化合物 4 在三层器件中可作为亮蓝色发光体和空穴传输分子。正如复合物 [2-(Zn(O2CCF3)2]2 (5) 的合成和结构所示,分子 1-3 中的二吡啶基氨基官能团能够与金属离子(如 Zn(II))螯合。Zn(II) 离子与二吡啶基结合会降低配体 2 的发射效率。