Key Laboratory of Green Chemistry & Technology of Ministry of Education, College of Chemistry, State Key Laboratory of Biotherapy, and Healthy Food Evaluation Research Center, Sichuan University, Chengdu, China.
School of Pharmacy, Guangxi Medical University, Nanning, China.
Nat Chem. 2020 Jun;12(6):551-559. doi: 10.1038/s41557-020-0453-0. Epub 2020 Apr 20.
The generation of molecular chirality in the absence of any molecular chiral inductor is challenging and of fundamental interest for developing a better understanding of homochirality. Here, we show the manipulation of molecular chirality through control of the handedness of helical metal nanostructures (referred to as nanohelices) that are produced by glancing angle deposition onto a substrate that rotates in either a clockwise or counterclockwise direction. A prochiral molecule, 2-anthracenecarboxylic acid, is stereoselectively adsorbed on the metal nanohelices as enantiomorphous anti-head-to-head dimers. The dimers show either Si-Si or Re-Re facial stacking depending on the handedness of the nanohelices, which results in a specific enantiopreference during their photoinduced cyclodimerization: a left-handed nanohelix leads to the formation of (+)-cyclodimers, whereas a right-handed one gives (-)-cyclodimers. Density functional theory calculations, in good agreement with the experimental results, point to the enantioselectivity mainly arising from the selective spatial matching of either Si-Si or Re-Re facial stacking at the helical surface; it may also be influenced by chiroplasmonic effects.
在没有任何分子手性诱导剂的情况下产生分子手性具有挑战性，并且对于深入了解手性具有重要意义。在这里，我们展示了通过控制螺旋金属纳米结构（称为纳米螺旋）的手性来操纵分子手性，这些纳米结构是通过在以顺时针或逆时针方向旋转的基板上斜角沉积而产生的。一个前手性分子，2-蒽羧酸，作为对映体反头对头二聚体，在手性金属纳米螺旋上被立体选择性吸附。二聚体根据纳米螺旋的手性显示 Si-Si 或 Re-Re 面堆积，这导致其光诱导环二聚化过程中的特定对映体偏好：左手纳米螺旋导致（+）-环二聚体的形成，而右手纳米螺旋则导致（-）-环二聚体的形成。与实验结果非常吻合的密度泛函理论计算表明，对映选择性主要源于在螺旋表面上 Si-Si 或 Re-Re 面堆积的选择性空间匹配；它也可能受到手性等离子体效应的影响。
