• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Chemistry: A European journal >Extension of Conjugation Leading to Bathochromic or Hypsochromic Effects in OPV Series
【24h】

Extension of Conjugation Leading to Bathochromic or Hypsochromic Effects in OPV Series

机译：扩展共轭导致OPV系列中的红变色或七色变色效应

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Four OPV series 1-4 (a-d) with a terminal dialkylamino group as electron donor were prepared by Wittig-Horner reactions.To study the influence of the push-pull effect on the long-wavelength absorption,three of the four series contained terminal acceptor groups (CN,CHO,NO_2).The length of the chromophores strongly affects the intramolecular charge transfer (ICT)-an effect which superimposes upon the extension of the conjugation.Increasing numbers n of repeat units cause an overall bathochromic shift for the purely donor-substituted series 1a-4a and the series 1b-4b with CN as weak acceptor.The two effects annihilate each other in the series 1c-4 c with terminal CHO groups,so that the adsorption maxima are almost independent of the length of the chromophore.A hypsochromic shift is observed for the series 1d-4d,which contains the strong acceptor group NO_2.This anomaly disapperas on protonation of the dialkylamino group because the push-pull effect disappears in the ammonium salts.The results can be explained by semiempirical quantum mechanics (AM1,INDO/S).The HOMO-LUMO transition,which is mainly responsible for the ICT,becomes less important in the electron transitions S_0->S_1 when the distance between donor and acceptor is increased.The commonly used VB model,which contains an electroneutral and a zwitterionic resonance structure,is contrasted with a MO model with dipole segments at both ends of the OPV chains.The latter model turned out to be more appropriate-at least for donor-acceptor-substituted OPVs with n>=2.
机译：通过Wittig-Horner反应制备了四个带有末端二烷基氨基作为电子供体的OPV 1-4系列（ad）。为了研究推挽效应对长波吸收的影响，四个系列中的三个包含了末端受体发色团的长度强烈影响分子内电荷转移（ICT）-这种作用叠加在共轭作用的扩展上。重复单元数n的增加会导致纯供体的整体红移取代的1a-4a系列和1b-4b系列以CN为弱受体。这两个效应在带有末端CHO基团的1c-4c系列中相互抵消，因此吸附最大值几乎与发色团的长度无关观察到1d-4d系列含有一个强受体基团NO_2的低变色现象。由于烷基盐中的推挽效应消失了，因此该异常在二烷基氨基的质子化过程中消失。 ult可以用半经验量子力学（AM1，INDO / S）来解释。当供体和受体之间的距离增加时，主要负责ICT的HOMO-LUMO跃迁在电子跃迁S_0-> S_1中的重要性降低。常用的包含电子中性和两性离子共振结构的VB模型与OPV链两端均具有偶极段的MO模型形成对比。后者模型更合适-至少对于供体-受体n> = 2的取代的OPV。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号