External electric field control: driving the reactivity of metal-free azide-alkyne click reactions
External electric field control: driving the reactivity of metal-free azide-alkyne click reactions
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DOI：
10.1039/c7cp04202g
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发表时间：
2017-09-07
影响因子：
3.3
通讯作者：
Datta, Ayan
中科院分区：
文献类型：
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作者：
Bhattacharyya, Kalishankar;Karmakar, Sharmistha;Datta, Ayan
最近的报告表明，外电场（EEF）可以帮助甚至控制产品的选择性。在这项工作中，我们已经证明，当沿反应轴施加定向EEF时，烷基（芳基）叠氮化物和环辛基（双氟环辛基）之间的Huisgen反应的势垒降低了类似于3-4千卡摩尔（-1）。由于它们固有的极性过渡态（TSs）， EEF的平行取向导致碎片之间的电荷转移（CT）增强，并伴随着沿反应轴的偶极矩增加。这导致在0.3-0.5 V A（-1）范围内的中等EEFs的反应速率增加。由于高极性和定向环境在生物环境中无处不在，无金属点击反应可以进一步加速活细胞的非侵入性成像。从概念上讲，电场控制似乎是一种驱动甚至可能调节有机分子反应性的新工具（催化剂）。
Recent reports have suggested that an external electric field (EEF) can assist and even control product selectivity. In this work, we have shown that the barrier for the Huisgen reaction between alkyl (aryl) azide and cyclooctyne(biflurocyclooctyne) is reduced by similar to 3-4 kcal mol(-1) when an oriented EEF is applied along the reaction axis. As a consequence of their inherently polar transition-states (TSs), a parallel orientation of the EEF results in enhancement of the charge transfer (CT) between the fragments and concomitant increase in the dipole moment along the reaction axes. This leads to an increase in the reaction rate for moderate EEFs in the range of 0.3-0.5 V A(-1). Since highly polar and directional environments are omnipresent in biological environments, metal-free click reactions can be further accelerated for non-invasive imaging of live-cells. Conceptually, electric field control appears to be a novel tool (catalyst) to drive, and possibly even tune, the reactivity of organic molecules.