Department of Chemistry, Marquette University , P.O. Box 1881, Milwaukee, Wisconsin 53201-1881, United States.
J Am Chem Soc. 2017 Mar 29;139(12):4334-4337. doi: 10.1021/jacs.7b01226. Epub 2017 Mar 16.
Typical poly-p-phenylene wires are characterized by strong interchromophoric electronic coupling with redox and optical properties being highly length-dependent. Herein we show that an incorporation of a pair of para-methoxy groups at each p-phenylene unit in poly-p-phenylene wires (i.e., PHE) changes the nodal structure of HOMO that leads to length-invariant oxidation potentials and cation radical excitation energies. As such, PHE represents a unique class of isoenergetic wires where hole delocalization mainly occurs via dynamic hopping and thus may serve as an efficient medium for long-range charge transfer. Availability of these wires will allow demonstration of long-range electron transfer via incoherent hopping using donor-bridge-acceptor systems with isoenergetic PHE-based wires as bridges.
典型的聚对亚苯基线的特点是与氧化还原和光学性质高度相关的强发色团间电子偶联，这些性质高度依赖于长度。本文中我们表明，在聚对亚苯基线（即 PHE）的每个对亚苯基单元中引入一对间甲氧基，会改变 HOMO 的节点结构，从而导致氧化电位和阳离子自由基激发能与长度无关。因此，PHE 代表了一类独特的等能量线，其中空穴离域主要通过动态跳跃发生，因此可能作为长程电荷转移的有效介质。这些线材的可用性将允许通过供体-桥-受体系统使用基于等能量 PHE 的线材作为桥来展示通过非相干跳跃的长程电子转移。
