A series of novel donor–acceptor type borondipyrromethene (BODIPY)-tethered triphenylamine conjugates (BDP4–8) containing one or two BODIPY cores attached to a triphenylamine scaffold at the 4- or 4,4′- positions were successfully synthesised via a mild and effective protocol. Their photophysical and electrochemical properties were investigated. The absorption spectra indicated that the meso-substituted BODIPY with triphenylamine did not give rise to an intense intramolecular charge transfer (ICT) and did not effectively extend the conjugated length compared with substitution at the 2,6- and 3,5-positions as previously reported. It is worth noticing that the asymmetric mono-BODIPY-tethered triphenylamine conjugates (BDP5, BDP7) showed an electronic distribution imbalance due to the special 3D propeller shape of triphenylamine resulting in twisted molecular space configurations. In contrast, the symmetric bis-BODIPY-tethered triphenylamine conjugates (BDP4, BDP6, and BDP8) exhibited a balanced electronic distribution. The photoluminescence spectra of these conjugates exhibited significant Stokes shifts (5300–6700 cm–1), which caused fluorescence emission spectra in near-infrared regions. Cyclic voltammograms reveal that the asymmetric mono-BODIPY-tethered triphenylamine conjugates (BDP5, BDP7) have higher LUMO energy levels and lower HOMO energy levels, thus resulting in larger bandgaps than the bis-BODIPY-tethered triphenylamine ones.
通过一种温和有效的方法,成功合成了一系列新型供体-受体型
硼二
吡咯并
乙烯(BODIPY)-系链
三苯胺共轭物(
BDP4-8),这些共轭物含有一个或两个 BODIPY 核心,并在 4- 或 4,4′- 位连接到
三苯胺支架上。研究了它们的光物理和电
化学特性。吸收光谱表明,与之前报道的在 2,6- 位和 3,5- 位取代相比,
三苯胺介观取代的 BODIPY 没有产生强烈的分子内电荷转移(ICT),也没有有效地延长共轭长度。值得注意的是,由于
三苯胺特殊的三维螺旋桨形状导致分子空间构型扭曲,不对称的单 BODIPY 系
三苯胺共轭物(
BDP5、
BDP7)显示出电子分布不平衡。相比之下,对称的双 BODIPY 系
三苯胺共轭物(
BDP4、
BDP6 和
BDP8)则表现出平衡的电子分布。这些共轭物的光致发光光谱表现出明显的斯托克斯偏移(5300-6700 cm-1),从而导致荧光发射光谱位于近红外区域。循环伏安图显示,不对称的单 BODIPY 系
三苯胺共轭物(
BDP5 和
BDP7)具有较高的 LUMO 能级和较低的 HOMO 能级,因此比双 BODIPY 系
三苯胺共轭物具有更大的带隙。