Stereochemistry-dependent structure of hydrogen-bonded protonated dimers: The case of 1-amino-indanol
Stereochemistry-dependent structure of hydrogen-bonded protonated dimers: The case of 1-amino-indanol
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氢键质子化二聚体的立体化学依赖性结构：1-氨基-茚满醇的情况
DOI：
10.1039/c8cp00787j
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
A. Zehnacker
中科院分区：
文献类型：
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作者：
A. Bouchet;J. Klyne;S. Ishiuchi;O. Dopfer;M. Fujii;A. Zehnacker
为了理解手性在塑造生物超分子体系中的作用，在分子水平上可视化立体化学对模型聚集体结构的微妙影响是有指导意义的。在此，我们应用保形特定的红外-紫外双共振激光光谱在冷离子阱中导出质子化的同源二聚体的（1 R，2S）-顺式-和（1 R，2 R）-反式-1-氨基-2-茚满醇（c-Al ~ 2 H ~+，t-Al ~ 2 H ~+）的详细描述。虽然质子化单体（c-AIH+，t-AIH+）的区别仅在于一个碳原子的手性，但它们的构象明显不同。c-AIH+具有分子内NH+-O氢键（H-键），而t-AIH+缺乏这种相互作用。这对相应的c-Al 2 H+和t-Al 2 H+二聚体的几何形状和稳定性具有重要影响。虽然在c-Al 2 H+中分子内和分子间H-键之间存在竞争，但t-Al 2 H+的形成不需要单体的变形。这种差异导致t-Al 2 H+的结合能高于c-Al 2 H+。为了优化氢键网络，两种二聚体不一定涉及相应的最稳定的单体。c-Al 2 H+和t-Al 2 H+在它们的UV光解离质谱和它们的电子光谱中不同，这表明在激发态中也有不同的几何结构。
To understand the role of chirality in shaping biological supramolecular systems it is instructive to visualize the subtle effects of stereochemistry on the structure of model aggregates at the molecular level. Here, we apply conformer-specific IR-UV double-resonance laser spectroscopy in a cold ion trap to derive a detailed description of the protonated homodimers of (1R,2S)-cis- and (1R,2R)-trans-1-amino-2-indanol (c-AI2H+, t-AI2H+). Although the protonated monomers (c-AIH+, t-AIH+) only differ by the chirality of one carbon atom, their conformations are clearly distinct. c-AIH+ has an intramolecular NH+⋯O hydrogen bond (H-bond), while t-AIH+ lacks such an interaction. This has crucial consequences on the geometry and stability of the corresponding c-AI2H+ and t-AI2H+ dimers. While there is a competition between intra- and intermolecular H-bonds in c-AI2H+, the formation of t-AI2H+ does not require deformation of the monomers. This difference results in higher binding energies of t-AI2H+ compared to c-AI2H+. To optimize the H-bond network, the two dimers do not necessarily involve the corresponding most stable monomers. c-AI2H+ and t-AI2H+ differ in their UV photodissociation mass spectra and in their electronic spectra, which suggests different geometries also in the excited state.