Department of Chemistry, Wilfrid Laurier University , Waterloo, N2L 3C5 Ontario, Canada.
J Am Chem Soc. 2014 Dec 24;136(51):17757-61. doi: 10.1021/ja5084267. Epub 2014 Dec 15.
We establish helical gold nanorods as the first examples of chiral recognition nanostructures by examining the simple chiral molecule CClHDT adsorbed on the helical Au40 nanorod. We calculate the vibrational circular dichroism (VCD) spectra of the R and S enantiomers of CClHDT adsorbed on the R (or S) enantiomer of Au40 using relativistic density functional theory. The highest adsorption energy is found when the Cl atom of CClHDT binds to a low-coordinated Au atom at the edge of Au40. There are three adsorption modes (essentially identical in energy) corresponding to three orientations of the HDT moiety. We show that, for each adsorption mode, the VCD spectra are distinctly different for the Au40(R)-ClHDT(R) and Au40(R)-CClHDT(S) complexes, and we give a qualitative explanation for this based on the principle of chirality transfer. For comparison with the results for Au40, we calculate the VCD spectra of the R and S enantiomers of CClHDT adsorbed on the achiral Au20 tetrahedral cluster. Again, there are three adsorption modes (essentially identical in energy) corresponding to three orientations of the HDT moiety. However, we show that, for each adsorption mode, the VCD spectra are mirror symmetric but otherwise essentially identical for the Au20-CClHDT(R) and Au20-CClHDT(S) complexes. Thus, the inherent chirality of the helical Au40 nanorod is essential for its chiral recognition functionality.
我们通过研究手性分子 CClHDT 在螺旋 Au40 纳米棒上的吸附，确立了螺旋金纳米棒作为首例手性识别纳米结构的地位。我们使用相对论密度泛函理论计算了吸附在 R（或 S）对映体 Au40 上的 CClHDT 的 R 和 S 对映异构体的振动圆二色性（VCD）谱。当 CClHDT 的 Cl 原子与 Au40 边缘的低配位 Au 原子结合时，吸附能最高。有三种吸附模式（能量基本相同）对应于 HDT 部分的三个取向。我们表明，对于每种吸附模式，Au40(R)-ClHDT(R) 和 Au40(R)-CClHDT(S) 配合物的 VCD 谱明显不同，我们基于手性转移原理对此进行了定性解释。为了与 Au40 的结果进行比较，我们计算了吸附在非手性 Au20 四面体簇上的 CClHDT 的 R 和 S 对映异构体的 VCD 谱。同样，有三种吸附模式（能量基本相同）对应于 HDT 部分的三个取向。然而，我们表明，对于每种吸附模式，VCD 谱对于 Au20-CClHDT(R) 和 Au20-CClHDT(S) 配合物是镜像对称的，但在其他方面基本相同。因此，螺旋 Au40 纳米棒的固有手性对于其手性识别功能至关重要。
