Investigating the Enantioselectivity of Alanine on a Chiral Cu{421}R Surface

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• 作者：Lars Thomsen ; Anton Tadich ; Daniel P. Riley ; Bruce C. C. Cowie ; Michael J. Gladys
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：May 3, 2012
• 年：2012
• 卷：116
• 期：17
• 页码：9472-9480
• 全文大小：702K
• 年卷期：v.116,no.17(May 3, 2012)
• ISSN：1932-7455

文摘

Saturated chemisorbed layers of d- and l-alanine amino acids were adsorbed onto a chiral Cu{421}^R surface. Very little enantioselectivity was observed in the HR-XPS thermal desorption; however, there was a large difference in the dissociation products left on the surface between the two enantiomers. NEXAFS spectroscopy also exhibited only minor differences in the molecular adsorption of the two enantiomer layers; however, low-energy electron diffraction (LEED) images revealed significant differences in the structure of the adsorbed layers. d-alanine forms a p(2 脳 3) overlayer while l-alanine forms a combination of p(1 脳 2) overlayer and faceted steps oriented in the [鈭?10] direction. Intermolecular bonding and steric effects play a significant role in these stereoselective differences by maximizing the hydrogen bonding between the molecules. This study clearly shows that single chiral tests are not adequate to ascertain the true enantioselective properties of the given system.