Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan.
Condensed Molecular Materials Laboratory, RIKEN Cluster for Pioneering Research, RIKEN, Wako, Saitama, 351-0198, Japan.
Chemistry. 2019 Dec 5;25(68):15455-15462. doi: 10.1002/chem.201903667. Epub 2019 Oct 24.
Radical cations of bis(dianisylamino)-terminated oligo(p-phenylene)s (OPPs) with up to five phenyl moieties were characterized by means of UV/Vis-NIR and variable-temperature ESR spectroscopy to investigate the bridge-length-dependence on intramolecular charge/spin self-exchange between two nitrogen redox-active centers. Additionally, a comparative study between bis(dianisylamine)-based mixed-valence (MV) radical cations connected by p-terphenylene and hexa-peri-hexabenzocoronene (HBC) π-bridging units also provided information on the influence of extended π-conjugation over the OPP-bridge due to the planarization between adjacent phenylene units on the strength of electronic coupling. The present study on a homologous series of organic MV systems clarifies the attenuation factor through the OPP-bridge and the linear relationship between the electrochemical potential splitting and the electronic coupling in the region of intermediate-to-weak electronic coupling regime.
通过紫外/可见-近红外和变温电子顺磁共振光谱，对具有多达五个苯基部分的双（二苯胺基）封端的寡聚（对亚苯基）（OPPs）的自由基阳离子进行了表征，以研究桥长对两个氮氧化还原活性中心之间的分子内电荷/自旋自交换的影响。此外，通过 p-三联苯和六-对-六苯并-冠烯（HBC）π-桥联单元连接的基于双（二苯胺）的混合价（MV）自由基阳离子的对比研究也提供了关于扩展π共轭对 OPP 桥的影响的信息，这是由于相邻亚苯基单元之间的平面化导致电子耦合强度增强。该系列有机 MV 体系的研究阐明了通过 OPP 桥的衰减因子以及电化学势分裂与中间至弱电子耦合区域中电子耦合之间的线性关系。
