Synthesis of π-Conjugated Polymers Containing Organoboron Benzo[h]quinolate in the Main Chain
Synthesis of π-Conjugated Polymers Containing Organoboron Benzo[h]quinolate in the Main Chain
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DOI：
10.1021/ma100814v
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发表时间：
2010-07
期刊：
影响因子：
5.5
通讯作者：
Yuichiro Tokoro;A. Nagai;Y. Chujo
中科院分区：
文献类型：
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作者：
Yuichiro Tokoro;A. Nagai;Y. Chujo
近年来，有机硼染料作为一种具有良好光学性能的染料在各个领域受到了广泛的关注。由于发光量子产率高、消光系数大或双光子吸收截面大，它们被用作化学探针、光敏剂2和光学传感3。其中，8-羟基喹啉二苯基硼（BPh2q） 4等有机硼酸盐由于其良好的热稳定性和高的发射量子产率而成为有机发光二极管（oled）的替代品。BPh2q及其衍生物从基于喹啉的配体内电荷转移（ILCT）激发态发射强光。当最高占据分子轨道（HOMO）和最低未占据分子轨道（LUMO）分别定位在喹啉配体的酚酸环和吡啶环上时，这种ILCT状态就形成了。通过共价键将其引入聚合物是有利的，因为它改善了可加工性，如成膜性、热稳定性和光稳定性等。Jäkle等人首先报道了通过聚（4-二溴硼基苯乙烯）的多级聚合反应合成了包含在聚苯乙烯侧链上的定义良好的聚合物，7和Weck等人也提出了有机喹啉硼酸官能化聚苯乙烯作为oled的优秀前驱体的潜力。最近，我们还制备了含有有机喹啉硼酸盐的共轭聚合物，其中对苯乙烯单元嵌入到聚合物骨架中的硼原子上。这些聚合物发出强烈的绿色荧光，并且观察到从具有高摩尔吸收系数的共轭连接剂到硼醌酸酯部分的有效能量迁移。q -配体上的取代基可以改变聚合物的发射色；例如，甲基取代的有机硼喹啉聚合物表现出绿蓝色或蓝色的光致发光。10诸如氧、硫和硒等元素也影响有机硼喹啉聚合物的发射波长。随着硼原子附近16基团原子序数的增加，低分子质量模型化合物和聚合物的发射波长向更长波偏移，绝对量子产率下降。
Organoboron dyes have recently found widespread interest as species with promising optical properties in various fields. They have been used as chemical probes, 1 photosensitizers, 2 and optical sensing3 due to high luminescent quantum yields, large extinction coefficients, or two-photon absorption cross section. Among them, organoboron quinolates such as 8-hydroxyquinolinatediphenylboron (BPh2q) 4 turned out to be attractive as an alternative to tris (8-hydroxyquinolinate) aluminum (Alq3) 5 for organic light-emitting diodes (OLEDs) because of their good thermal stabilities as well as the high emission quantum yields. BPh2q and their derivatives emit intense light from a quinolinebased intraligand charge transfer (ILCT) excited state. 6 This ILCT state is formed when the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) are localized on the phenolate ring and on the pyridyl ring of the quinoline ligand, respectively. Introduction into polymers by covalent bonding is expected to be advantageous because of the improved processability such as film formability, thermal stability, and photostability, etc. Jäkle et al. first reported the synthesis of well-defined polymers incorporated into the polystyrene side chain via multistage polymeric reaction of poly (4-dibromoborylstyrene), 7 and Weck et al. also proposed the potentiality of organoboron quinolate-functionalized polystyrene as the excellent precursors for OLEDs. 8Recently, we have also prepared organoboron quinolate-containing conjugated polymers, in which p-phenyleneethynylene units were embedded to boron atoms in the polymer backbones. 9 Those polymers gave strong green fluorescence, and an efficient energy migration from conjugated linkers with high molar absorption coefficient to boron quinolate moieties was observed. Substituting groups on the Q-ligand moiety can change the emission color of the polymers; ie, polymers with methylsubstituted organoboron quinolate polymers exhibited greenblue or blue photoluminescence. 10 Elements such as oxygen, sulfur, and selenium also affect the emission wavelength of the organoboron quinolate polymer. 11 Increasing of atomic number of the 16 group atom adjacent to the boron atom caused emission shift to longer wavelength and decreasing of absolute quantum yields for both the low-molecular-mass model compounds and the polymers.