Controlling the Charge Transfer in D–A–D Chromophores Based on Pyrazine Derivatives
作者:Xuefeng Lu、Suhua Fan、Jinhong Wu、Xiaowei Jia、Zhong-Sheng Wang、Gang Zhou
DOI:10.1021/jo500856k
日期:2014.7.18
interaction and expanding the absorption spectrum. Typically, when a thiophene ring is fused on the Qx unit in DQxD, a near-infrared dye is realized in simple chromophore DTQD, which displays the maximum absorption wavelength at 716 nm with the threshold over 900 nm. This is probably due to the enhanced charge density on the acceptor moiety and better orbital overlap, as revealed by theoretical calculation
一系列带有各种吸电子基团的对称供体-受体-供体(D–A–D)发色团,例如喹喔啉(Qx),苯并[ g ]喹喔啉(BQ),吩嗪(Pz),苯并[ b ]吩嗪(BP),噻吩并[3,4- b ]吡嗪(TP)和噻吩并[3,4- b ]喹喔啉(TQ),已经过设计和合成。由于吡嗪环中两个亚胺氮的吸电子特性和两个三苯胺中另外两个胺氮的给电子性,可以发现所有发色团的分子内电荷转移(ICT)相互作用。苯环或噻吩环在吡嗪受体单元上融合后,ICT相互作用会增强,导致ICT的红移。此外,噻吩环在扩大ICT相互作用和扩大吸收光谱方面优于苯环。通常,将噻吩环稠合在DQxD的Qx单元上时,可以在简单的生色团DTQD中实现近红外染料,在716 nm处显示最大吸收波长,阈值超过900 nm。如理论计算所揭示的,这可能是由于受体部分上电荷密度的提高和更好的轨道重叠。这些结果表明,在垂直于D–A–D主链的方向上扩展吡嗪受体的共轭可显着改善ICT相互作用。