Farrokhpour Hossein, Hassanjani Kousar, Najafi Chermahini Alireza, Eskandari Kiamars
Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111, Iran.
J Phys Chem A. 2024 May 2;128(17):3285-3300. doi: 10.1021/acs.jpca.4c00699. Epub 2024 Apr 17.
In this work, the discrimination of the enantiomers of cysteine (l- and d-CYS) using the chiral Au and Ag@Au clusters was theoretically investigated in the gas phase and water. Two modes were considered for the interaction of each enantiomer with the clusters (via only its S atom or its S atom and NH group, simultaneously). The interaction energy () and adsorption energy () for the complexation of each enantiomer with the clusters for each interaction mode were calculated. Considering the calculated interaction energies, the interaction of d-CYS with Au is stronger than that of l-CYS with the same cluster. Also, it was observed that the substitution of the Au core of the Au cluster with the Ag cluster caused the increase of the interaction energy of l-CYS with the Ag@Au cluster compared to the Au cluster, while the reverse trend was observed for d-CYS. Quantum theory of atoms in molecules (QTAIM) analysis was employed to calculate the interaction paths and their related bond critical points (BCPs) between the CYS enantiomers and the clusters to explain the difference between the interaction energy of the enantiomers with the clusters. The IR, normal Raman (NR), and surface-enhanced Raman scattering (SERS) spectra of the enantiomers interacting with the Au and Ag@Au clusters were calculated, and the discrimination between l-CYS and d-CYS using the calculated spectra was explained. It was found that the discrimination of the enantiomers based on their interaction with the clusters is controlled by the charge transfer between the enantiomers and the clusters.
在这项工作中，从理论上研究了手性金簇和银@金簇在气相和水中对半胱氨酸对映体（L-和D-半胱氨酸）的识别。考虑了每种对映体与簇相互作用的两种模式（仅通过其硫原子或同时通过其硫原子和氨基）。计算了每种对映体与簇在每种相互作用模式下络合的相互作用能（）和吸附能（）。考虑计算得到的相互作用能，D-半胱氨酸与金的相互作用比L-半胱氨酸与同一簇的相互作用更强。此外，还观察到用银簇取代金簇的金核会导致L-半胱氨酸与银@金簇的相互作用能相对于金簇增加，而D-半胱氨酸则呈现相反的趋势。采用分子中的原子量子理论（QTAIM）分析来计算半胱氨酸对映体与簇之间的相互作用路径及其相关的键临界点（BCP），以解释对映体与簇相互作用能之间的差异。计算了与金簇和银@金簇相互作用的对映体的红外光谱、普通拉曼光谱（NR）和表面增强拉曼散射光谱（SERS），并解释了利用计算光谱对L-半胱氨酸和D-半胱氨酸的鉴别。结果发现，基于对映体与簇相互作用的鉴别受对映体与簇之间电荷转移的控制。
