The effect of isotopic substitution on the chirality of a self-assembled helix
The effect of isotopic substitution on the chirality of a self-assembled helix
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DOI：
10.1038/nchem.889
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发表时间：
2011-01-01
期刊：
影响因子：
21.8
通讯作者：
Meijer, E. W.
中科院分区：
文献类型：
--
作者：
Cantekin, Seda;Balkenende, Diederik W. R.;Meijer, E. W.
N， N‘， N’ -三烷基苯-1,3,5-三羧基酰胺（BTAs）通过强的，三重α -螺旋型分子间氢键自组装成明确的，螺旋的，一维柱状聚集体。当在这些bta的烷基侧链中引入立体中心时，在稀极性溶液中观察到强烈的棉花效应，表明一种螺旋构象比另一种更受青睐。在这里，我们报道通过在烷基侧链中引入氘/氢同位素手性，在自组装bta中产生螺旋感偏好。我们通过进行构象分析来确定这些氘化超分子聚合物的左旋和右旋螺旋构象的相对稳定性。我们的研究结果表明，bta基超分子聚合物和螺旋型多异氰酸酯的氘/氢取代结果非常相似，尽管形成机制不同。本文讨论的选择性氘化bta是由同位素取代引起的超分子手性的第一个例子。
N, N', N''-trialkylbenzene-1,3,5-tricarboxamides (BTAs) self-assemble by means of strong, threefold alpha-helix-type intermolecular hydrogen bonding into well-defined, helical, one-dimensional columnar aggregates. When a stereogenic centre is introduced into the alkyl side chains of these BTAs, strong Cotton effects are observed in dilute apolar solutions, indicating the preference for one helical conformation over the other. Here, we report the creation of a helical sense preference in self-assembled BTAs by introducing deuterium/hydrogen isotope chirality into the alkyl side chains. We determine the relative stabilities of the left-and right-handed helical conformations of these deuterated supramolecular polymers by performing a conformational analysis. Our findings show that the results of deuterium/hydrogen substitution in BTA-based supramolecular polymers and helical polyisocyanates are very similar, although the formation mechanisms differ. The selectively deuterated BTAs discussed here represent the first example of supramolecular chirality resulting from isotope substitution.