Martin Colin J, Fukui Tomoya, Takehara Ryosuke, Fujii Shintaro, Fukushima Takanori
Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan.
Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan.
Precis Chem. 2023 Aug 4;1(6):388-394. doi: 10.1021/prechem.3c00070. eCollection 2023 Aug 28.
A break junction technique has been established to explore conductive behavior at the single molecular level, and recent interest has shifted toward the evaluation of bimolecular systems interacting through noncovalent intermolecular forces. This requires precise control over the orientation of the two molecules so that they can adapt an appropriate face-to-face arrangement between two electrodes. Herein, we present an approach using a tripodal triptycene scaffold that allows for accurate positioning of electroactive subunits with an upright configuration on substrate surfaces. We incorporated electron-donating tetrathiafulvalene or electron-accepting anthraquinone into the molecular scaffold and confirmed that the resulting molecules retain the electronic properties particular to their attached subunits. Self-assembled monolayers (SAMs) of these molecules were prepared on Au(111) and characterized by XPS and STM. STM break junction techniques were applied to the SAMs, revealing two electrical conduction regimes; one arises from single-molecules sandwiched between two electrodes, and the second from intermolecularly interacting homodimers that bridge between electrodes. This observation demonstrates the validity of the approach of using tripodal triptycene scaffolds to precisely direct electroactive subunits to undergo intermolecular pairing. We believe that the present work will provide a new avenue for evaluating the heterodimers at the single molecular level.
一种断裂结技术已被建立起来，用于探索单分子水平上的导电行为，并且最近的研究兴趣已转向对通过非共价分子间力相互作用的双分子体系的评估。这需要精确控制两个分子的取向，以便它们能够在两个电极之间形成合适的面对面排列。在此，我们提出一种使用三脚架型三蝶烯支架的方法，该方法能够使电活性亚基以直立构型精确地定位在基底表面上。我们将供电子的四硫富瓦烯或吸电子的蒽醌引入到分子支架中，并证实所得分子保留了其连接亚基特有的电子性质。这些分子的自组装单分子层（SAMs）在Au(111)上制备，并通过XPS和STM进行表征。STM断裂结技术应用于SAMs，揭示了两种导电机制；一种源于夹在两个电极之间的单分子，另一种源于在电极之间桥连的分子间相互作用的同二聚体。这一观察结果证明了使用三脚架型三蝶烯支架精确引导电活性亚基进行分子间配对方法的有效性。我们相信，目前的工作将为在单分子水平上评估异二聚体提供一条新途径。
