With the aim of designing molecular wires operating at easily accessible potentials, a series of soluble bis-donor polyenic compounds (up to 3.2 nm long) has been prepared. Their optical and electrochemical properties have been investigated. These model compounds were shown to exhibit a reversible two-electron oxidation process at low potential (which further decreases with increasing polyenic chain length). The oxidized dicationic species combine convenient stability and solubility. Interestingly, these species also show reduced bond length alternation along the polyenic chain, consistent with a significant red-shift of their absorption band to the NIR region. Such behaviour is expected to lead to a dramatic enhancement of the third-order nonlinear optical responses of the polyenic molecules upon oxidation, opening the way to optical switches. Hence, such molecules represent promising model compounds for molecular wires but also open an innovative route towards voltage-driven optical switches.
为了设计在易于接近的电势下工作的分子线,制备了一系列可溶性双供体多
烯化合物(长达 3.2 nm)。对其光学和电
化学性质进行了研究。这些模型化合物在低电位下表现出可逆的双电子
氧化过程(随着多
烯链长度的增加而进一步降低)。
氧化双阳离子物质结合了便利的稳定性和溶解度。有趣的是,这些物质还显示出沿着多
烯链的键长交替减少,这与它们的吸收带向近红外区域的显着红移一致。这种行为预计将导致
氧化时多
烯分子的三阶非线性光学响应的显着增强,从而为光开关开辟道路。因此,此类分子代表了分子线的有前途的模型化合物,同时也开辟了一条通向电压驱动光开关的创新途径。