Flow‐Chemistry‐Enabled Synthesis of 5‐Diethylboryl‐2,3′‐bipyridine and Its Self‐Assembly Dynamics
Flow‐Chemistry‐Enabled Synthesis of 5‐Diethylboryl‐2,3′‐bipyridine and Its Self‐Assembly Dynamics
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5-二乙基硼基-2,3-联吡啶的流动化学合成及其自组装动力学
DOI：
10.1002/chem.202202882
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Nagaki Aiichiro
中科院分区：
文献类型：
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作者：
Wakabayashi Shigeharu;Takumi Masahiro;Kamio Shintaro;Wakioka Masayuki;Ohki Yasuhiro;Nagaki Aiichiro
采用流动微反应器合成了传统间歇法难以合成的5-二乙基硼基-2，3 ′-联吡啶（1）。化合物1作为环状三聚体和环状四聚体在溶液中的平衡混合物获得，后者在苯中通过己烷的蒸气扩散在7 °C下结晶。通过溶剂和浓度依赖性实验证实了该系统的动态性质。值得注意的是，通过使用流动NMR光谱验证了动力学，其揭示了达到平衡所需的时间受到溶剂比的影响（在[D 6]丙酮和C6 D 6的2：1、1：1和1：2混合物中分别<18s、24-28 s和34-42 s）。 化合物1和3-[4′-（二乙基硼基）苯基]吡啶（2）在溶液和晶体中表现出不同的自组装行为。密度泛函理论计算表明，这种差异在很大程度上是由于两个连续的芳环之间的平面性增强。
5‐Diethylboryl‐2,3′‐bipyridine (1), which is inaccessible by conventional batch methods, was synthesized by using a flow microreactor. Compound1was obtained as an equilibrium mixture of a cyclic trimer and a cyclic tetramer in solution, the latter of which was crystallized in benzene by vapor diffusion of hexane at 7 °C. The dynamic nature of this system was confirmed by solvent‐ and concentration‐dependent experiments. Notably, the dynamics was verified by using flow NMR spectroscopy, which revealed that the time required to reach equilibrium was influenced by the solvent ratio (<18 s, 24–28 s, and 34–42 s in 2 : 1, 1 : 1, and 1 : 2 mixtures of [D6]acetone and C6D6, respectively). Compound1and 3‐[4′‐(diethylboryl)phenyl]pyridine (2) exhibited different self‐assembly behavior in solution and crystals. Density functional theory calculations suggested that this difference was largely due to enhanced planarity between two consecutive aromatic rings.