Designing Conical Intersections for Light-Driven Single Molecule Rotary Motors: From Precessional to Axial Motion
Designing Conical Intersections for Light-Driven Single Molecule Rotary Motors: From Precessional to Axial Motion
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DOI：
10.1021/jo5004289
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发表时间：
2014-04-18
影响因子：
3.6
通讯作者：
Olivucci, Massimo
中科院分区：
文献类型：
--
作者：
Filatov, Michael;Olivucci, Massimo
在过去，光驱动的单分子旋转马达的设计主要是通过修改它们的基态构象性质来指导的。因此，通过详细了解系统的光诱导动力学以及通过引入化学修饰来调节它的方式，可能会在这一领域取得进一步的进展。在目前的理论工作中，模型有机发色团和合成的旋转马达的分析用于合理化的吸电子杂原子（如阳离子氮）的地形和分支平面的机械相关的圆锥形交叉的影响。这种分析揭示了旋转运动的性质如何从旋进运动转变为轴向旋转运动。然后，这些概念被用来设计和构建三种不同类型的席夫碱旋转马达的量子化学模型。这些模型之一，具有合成可行的indanylidenepyrroline框架，具有圆锥形交叉结构，与不受基态构象障碍阻碍的轴向旋转一致。预计这种类型的马达应该能够将光子能量转换成特定的旋转模式，从而实现与在视色素中看到的那些相当的光异构化量子效率。
In the past, the design of light-driven single molecule rotary motors has been mainly guided by the modification of their ground-state conformational properties. Further progress in this field is thus likely to be achieved through a detailed understanding of light-induced dynamics of the system and the ways of modulating it by introducing chemical modifications. In the present theoretical work, the analysis of model organic chromophores and synthesized rotary motors is used for rationalizing the effect of electron-withdrawing heteroatoms (such as a cationic nitrogen) on the topography and branching plane of mechanistically relevant conical intersections. Such an analysis reveals how the character of rotary motion could be changed from a precessional motion to an axial rotational motion. These concepts are then used to design and build quantum chemical models of three distinct types of Schiff base rotary motors. One of these models, featuring the synthetically viable indanylidenepyrroline framework, has conical intersection structures consistent with an axial rotation not hindered by ground-state conformational barriers. It is expected that this type of motor should be capable of funneling the photon energy into specific rotary modes, thus achieving photoisomerization quantum efficiencies comparable to those seen in visual pigments.