Formation of Induced-Fit Chiral Templates by Amino Acid-Functionalized Pd(111) Surfaces
Formation of Induced-Fit Chiral Templates by Amino Acid-Functionalized Pd(111) Surfaces
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氨基酸功能化 Pd(111) 表面诱导拟合手性模板的形成
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
W. Tysoe
中科院分区：
文献类型：
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作者：
M. Mahapatra;L. Burkholder;Sunil P. Devarajan;Anibal Boscoboinik;M. Garvey;Yun Bai;W. Tysoe
手性探针分子，环氧丙烷和缩水甘油被用来测量一系列的氨基酸官能化的Pd（111）表面的对映选择性。只有那些含有四聚体氨基酸组件的表面被发现是对映选择性的，这表明它们作为手性模板，其中几个改性剂协同作用，形成一个手性反应口袋。先前已经表明，四聚体从反平行的阴离子-两性离子二聚体组装，其中三个氨基酸然后经历一致的平移运动以形成更稳定的四聚体。然而，密度泛函理论计算表明，最稳定的四聚体有一个口袋，是太小，以容纳手性探针，而更开放的反平行的阴离子-两性离子二聚体结构提供了足够的空间的环氧化物上最稳定的顶部钯吸附位点的对映选择性吸附。氨基酸的不稳定性被证实其较低的解吸温度测量的。
Chiral probe molecules, propylene oxide, and glycidol are used to measure the enantioselectivity of a range of amino acid-functionalized Pd(111) surfaces. Only those surfaces that contain tetrameric amino acid assemblies are found to be enantioselective, indicating that they act as chiral templates in which several modifiers operate in concert to form a chiral reaction pocket. It has previously been shown that the tetramers assemble from antiparallel anionic–zwitterionic dimers where three of the amino acids then undergo a concerted translational motion to form a more stable tetramer. However, density functional theory calculations reveal that the most stable tetramer has a pocket that is too small to accommodate the chiral probes, while the more open antiparallel anionic–zwitterionic dimer structure provides sufficient space for the epoxide to adsorb enantioselectively on the most stable atop palladium adsorption site. Amino acid destabilization is confirmed by its lower desorption temperature measured i...