Sorbonnes Universités, UPMC Univ Paris 06, UMR CNRS 7197, Laboratoire de Réactivité de Surface, 4 place jussieu, F-75005 Paris, France.
Langmuir. 2014 Jan 14;30(1):203-12. doi: 10.1021/la404262m. Epub 2013 Dec 19.
A combination of XPS, in situ RAIRS, LEED, and STM experiments together with ab initio DFT calculations were used to elucidate the self-assembly properties at the atomic level, and enabled the interpretation of the expression of surface chirality upon adsorption of both enantiomers of methionine on a clean Au(111) surface under UHV conditions. The combination of experimental results, in particular, LEED and STM data with quantum chemical calculations is shown to be a successful setup strategy for addressing this challenge. It was found that the methionine molecular self-assembly consists of the first molecule lying parallel to the gold surface and the second interacting with the first methionine through a 2D H-bond network. The interaction with the gold surface is weak. The stability of the assembly is mainly due to the presence of intermolecular H bonds, resulting in the formation of ziplike dimer rows on the Au(111) surface. The methionine molecules interact with each other via their amino acid functional groups. The assembly shows an asymmetric pattern due to a slightly different orientation of the methionine molecules with respect to the surface. Simulations of the STM image of methionine assemblies were consistent with the experimental STM image. The present study shows another example of Au(111) stabilizing a self-assembled biological layer, which is not chemically perturbed by the surface.
采用 XPS、原位 RAIRS、LEED 和 STM 实验以及从头算 DFT 计算相结合的方法，阐明了原子水平上的自组装特性，并解释了在超高真空条件下，手性表面在吸附两种甲硫氨酸对映体时的表达。实验结果，特别是 LEED 和 STM 数据与量子化学计算的结合，被证明是解决这一挑战的一种成功的策略。研究发现，甲硫氨酸分子的自组装由第一个分子平行于金表面组成，第二个分子通过二维氢键网络与第一个甲硫氨酸相互作用。与金表面的相互作用较弱。组装的稳定性主要归因于分子间氢键的存在，导致在 Au(111)表面上形成拉链状的二聚体行。甲硫氨酸分子通过其氨基酸官能团相互作用。由于甲硫氨酸分子相对于表面的取向略有不同，组装呈现出不对称的模式。甲硫氨酸组装的 STM 图像的模拟与实验 STM 图像一致。本研究展示了另一个例子，即在 Au(111)表面稳定自组装生物层，而表面不会受到化学干扰。
