Tuo De-Hui, Chen Chao, Ruan Huapeng, Wang Qi-Qiang, Ao Yu-Fei, Wang Xinping, Wang De-Xian
Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
Angew Chem Int Ed Engl. 2020 Aug 10;59(33):14040-14043. doi: 10.1002/anie.202003927. Epub 2020 Jun 8.
Radical pimers are the simplest and most important models for studying charge-transfer processes and provide deep insight into π-stacked organic materials. Notably, radical pimer systems with magnetic bi- or multistability may have important applications in switchable materials, thermal sensors, and information-storage media. However, no such systems have been reported. Herein, we describe a new pimer consisting of neutral N-(n-propyl) benzene triimide ([BTI-3C]) and its anionic radical ([BTI-3C] ) that exhibits rare magnetic multistability. The crystalline pimer was readily synthesized by reduction of BTI-3C with cobaltocene (CoCp ). The transition occurred with a thermal hysteresis loop that was 27 K wide in the range of 170-220 K, accompanied by a smaller loop with a width of 25 K at 220-242 K. The magnetic multistability was attributed to slippage of the π-stacked BTI structures and entropy-driven conformational isomerization of the side propyl chains in the crystalline state during temperature variation.
自由基二聚体是研究电荷转移过程最简单且最重要的模型，能深入洞察π堆积有机材料。值得注意的是，具有磁性双稳态或多稳态的自由基二聚体系统在可切换材料、热传感器和信息存储介质中可能有重要应用。然而，尚未有此类系统的报道。在此，我们描述了一种由中性N-(正丙基)苯三酰亚胺([BTI-3C])及其阴离子自由基([BTI-3C]⁻)组成的新型二聚体，它表现出罕见的磁性多稳态。该结晶二聚体通过用二茂钴(CoCp₂)还原BTI-3C很容易合成。转变发生时伴有一个热滞回线，在170 - 220 K范围内宽27 K，在220 - 242 K时伴有一个较小的宽度为25 K的回线。磁性多稳态归因于温度变化时晶体状态下π堆积BTI结构的滑移以及侧链丙基链的熵驱动构象异构化。
