The Importance of Attractive Three-Point Interaction in Enantioselective Surface Chemistry: Stereospecific Adsorption of Serine on the Intrinsically Chiral Cu{531} Surface
The Importance of Attractive Three-Point Interaction in Enantioselective Surface Chemistry: Stereospecific Adsorption of Serine on the Intrinsically Chiral Cu{531} Surface
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DOI：
10.1021/ja210499m
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发表时间：
2012-06-13
影响因子：
15
通讯作者：
Held, Georg
中科院分区：
文献类型：
--
作者：
Eralp, Tugce;Ievins, Alex;Held, Georg
丝氨酸的两种对映体都以两种不同的吸附几何形式吸附在固有的手性铜{531}表面上，这取决于覆盖度的不同。在饱和时，底物键通过羧酸基和氨基的两个氧原子形成(mu3配位)，而在低覆盖度时，通过去质子化的β-OH基团形成额外的键(mu4配位)。后者的吸附构型涉及底物键，分别通过手性中心的三个侧基，这导致了与仅涉及两个侧基的mu3配位相比，在吸附几何构型和能量上有明显更大的对映体差异。这个相对简单的模型体系表明，在直接比较中，三个侧基与底物的吸引作用比氢键或排斥作用更能有效地在多相手性催化体系中诱导强烈的对映体差异。
Both enantiomers of serine adsorb on the intrinsically chiral Cu{531} surface in two different adsorption geometries, depending on the coverage. At saturation, substrate bonds are formed through the two oxygen atoms of the carboxylate group and the amino group (mu 3 coordination), whereas at lower coverage, an additional bond is formed through the deprotonated beta-OH group (mu 4 coordination). The latter adsorption geometry involves substrate bonds through three side groups of the chiral center, respectively, which leads to significantly larger enantiomeric differences in adsorption geometries and energies compared to the mu 3 coordination, which involves only two side groups. This relatively simple model system demonstrates, in direct comparison, that attractive interactions of three side groups with the substrate are much more effective in inducing strong enantiomeric differences in heterogeneous chiral catalyst systems than hydrogen bonds or repulsive interactions.