首页> 外文OA文献 >Ferrocenyl helquats: unusual chiral organometallic nonlinear optical chromophores
【2h】

Ferrocenyl helquats: unusual chiral organometallic nonlinear optical chromophores

机译:二茂铁盔qua:不寻常的手性有机金属非线性光学发色团

代理获取
本网站仅为用户提供外文OA文献查询和代理获取服务,本网站没有原文。下单后我们将采用程序或人工为您竭诚获取高质量的原文,但由于OA文献来源多样且变更频繁,仍可能出现获取不到、文献不完整或与标题不符等情况,如果获取不到我们将提供退款服务。请知悉。

摘要

Three new dipolar cations have been synthesised, containing ferrocenyl (Fc) electron donor groups attached to helquat (Hq) acceptors. These organometallic Hq derivatives have been characterised as their TfO^− salts by using various techniques including NMR and electronic absorption spectroscopies and electrochemical measurements. UV–vis spectra show multiple intense low energy absorptions attributable to intramolecular charge-transfer (ICT) excitations. Each compound displays a reversible Fc^(+/0) redox process, together with two reversible one-electron reductions of the Hq fragment. Molecular quadratic nonlinear optical (NLO) responses have been determined by using hyper-Rayleigh scattering at 1064 nm, and Stark (electroabsorption) spectroscopic studies on the visible absorption bands. The obtained first hyperpolarizabilities β are moderate, consistent with the relatively short π-conjugation lengths between the Fc and attached pyridinium group. A single-crystal X-ray structure has been solved for one of the complexes as its PF_6^− salt, revealing a centrosymmetric packing in the triclinic space group P[1 with combining macron]. Density functional theory (DFT) and time-dependent DFT calculations indicate that the lowest energy absorption bands have mainly metal-to-ligand charge-transfer character. The donor orbitals involved in the electronic transitions forming the next lowest energy ICT band also have substantial contributions from the Fe atom. Good agreement between the simulated and experimental UV–vis absorption spectra is achieved by using the PBE0 functional with the 6-311++G(d)/LANL2DZ mixed basis set, and the theoretical β values are reasonably large. Oxidation of the Fc unit is predicted to cause the βtot value to decrease by more than 80% in one of the complexes.
机译:合成了三个新的偶极阳离子,它们包含连接到helquat(Hq)受体上的二茂铁基(Fc)电子供体基团。通过使用包括NMR和电子吸收光谱法以及电化学测量在内的各种技术,已将这些有机金属Hq衍生物表征为它们的TfO-盐。紫外可见光谱显示出多种强烈的低能量吸收,这归因于分子内电荷转移(ICT)激发。每种化合物都显示出可逆的Fc ^(+ / 0)氧化还原过程,以及Hq片段的两个可逆的单电子还原。分子二次非线性光学(NLO)反应已通过使用1064 nm处的超瑞利散射和可见光吸收带的Stark(电吸收)光谱研究确定。所获得的第一超极化率β是中等的,与Fc和连接的吡啶鎓基团之间的相对短的π-共轭长度一致。已经解决了其中一种配合物的单晶X射线结构,即其PF_6 ^-盐,揭示了三斜空间群P [1中结合了大分子]的中心对称堆积。密度泛函理论(DFT)和随时间变化的DFT计算表明,最低的能量吸收带主要具有金属到配体的电荷转移特性。构成次低能量ICT频段的电子跃迁中涉及的施主轨道也从Fe原子中获得了巨大贡献。通过将PBE0功能与6-311 ++ G(d)/ LANL2DZ混合基集配合使用,可以在模拟的UV-vis吸收光谱和实验的UV-vis吸收光谱之间取得良好的一致性,并且理论β值相当大。预测Fc单元的氧化会导致其中一种复合物的βtot值降低超过80%。

相似文献

  • 外文文献
  • 中文文献
  • 专利

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