Tuning the Surface Chemistry of Chiral Cu(531)S for Enhanced Enantiospecific Adsorption of Amino Acids
Tuning the Surface Chemistry of Chiral Cu(531)S for Enhanced Enantiospecific Adsorption of Amino Acids
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DOI：
10.1021/acs.jpcc.5b02695
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发表时间：
2015-07-09
影响因子：
3.7
通讯作者：
Han, Jeong Woo
中科院分区：
文献类型：
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作者：
Song, Ho Seong;Han, Jeong Woo
氨基酸是由胺和羧酸组成的重要生物有机化合物，因为它们是许多生物分子的主要组成部分。除甘氨酸外，它们都是手性的。因此，它们具有两种提供显着不同生物效应的对映体，因此需要将它们分离。高米勒指数金属表面通常定义本质上的手性结构。先前的许多研究已经证明了手性分子在这些表面上的对映特异性吸附差异。为了进一步增强对映专一性，一步修饰，即用第二种金属掺杂手性金属表面的扭结位点，可能是一种途径。它可能会导致吸附在表面上的一种对映体变得比另一种更稳定，从而导致更大的对映体特异性能量差异。在本研究中，我们进行了密度泛函理论（DFT）计算，系统地研究了丙氨酸、丝氨酸和半胱氨酸每种对映体的吸附几何形状和能量学，以及它们分别在纯、Pd、Pt和Au修饰的Cu(531)(S)上的对映特异性能量差异。通过用 Au 原子装饰扭结位点，在侧链与表面具有高亲和力的情况下，吸附的半胱氨酸的对映特异性显着增强了 0.08 eV。我们的结果为如何调整手性金属表面以扩大手性分子的对映特异性提供了有用的见解。
Amino acids are important bioorganic compounds composed of amine and carboxylic acid because they are the main building blocks of many biomolecules. All of them are chiral except glycine. Thus, they have two enantiomers which provide dramatically different biological effects, thereby requiring their separation. High Miller index metal surfaces often define intrinsically chiral structures. A number of previous studies have proved the enantiospecific adsorption difference of chiral molecules on those surfaces. To further enhance the enantiospecificity, step decoration, which is doping the kink site of chiral metal surface with a second metal, can be one route. It may induce one enantiomer adsorbed on the surface to become more stable than the other, inducing the larger enantiospecific energy difference. In this study, we performed density functional theory (DFT) calculations to systemically examine the adsorption geometries and energetics of each enantiomer of alanine, serine, and cysteine, and their enantiospecific energy differences on pure, Pd-, Pt-, and Au-decorated Cu(531)(S), respectively. By decorating the kinked site with an Au atom, the enantiospecificity of adsorbed cysteine was meaningfully enhanced by 0.08 eV, in the case when the side chain has a high affinity with the surface. Our results provide useful insight of how to tune chiral metal surfaces to enlarge the enantiospecificity of chiral molecules.