Spectroscopic and Computational Evidence of Intramolecular AuI⋅⋅⋅H+−N Hydrogen Bonding
Spectroscopic and Computational Evidence of Intramolecular AuI⋅⋅⋅H+−N Hydrogen Bonding
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DOI：
10.1002/anie.201811982
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发表时间：
2019-01
期刊：
影响因子：
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通讯作者：
M. Straka;Erik Andris;J. Vícha;A. Růžička;J. Roithová;L. Rulíšek
中科院分区：
文献类型：
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作者：
M. Straka;Erik Andris;J. Vícha;A. Růžička;J. Roithová;L. Rulíšek
尽管大量证据表明AuI化合物的一些X射线结构产生了短Au⋅⋅H−X接触，但这些体系中AuI⋅⋅H键的性质尚未得到清楚的了解。本文首次提出了[Cl - Au - L]+配合物中存在AuI⋅⋅⋅H+−N氢键的光谱证据，其中L是质子化的N杂环碳。该配合物在气相中被分离出来，并用氦标记红外光解（IRPD）光谱对其进行了表征，其中H+−N模式衍生的波段证明了分子内的AuI⋅⋅⋅H+−N键。量子化学计算再现了实验IRPD光谱，并允许表征分子内Au⋅⋅H+−N键，其r Au⋅⋅⋅H距离为2.17 Å，相互作用能约为−10 kcal mol−1。为Au⋅⋅⋅H+−N相互作用计算的各种化学键理论描述符为中等强度的氢键提供了强有力的证据。
Abstract Despite substantial evidence of short Au⋅⋅⋅H−X contacts derived from a number of X‐ray structures of AuI compounds, the nature of AuI⋅⋅⋅H bonding in these systems has not been clearly understood. Herein, we present the first spectroscopic evidence for an intramolecular AuI⋅⋅⋅H+−N hydrogen bond in a [Cl−Au−L]+ complex, where L is a protonated N‐heterocyclic carbene. The complex was isolated in the gas phase and characterized with helium‐tagging infrared photodissociation (IRPD) spectra, in which H+−N‐mode‐derived bands evidence the intramolecular AuI⋅⋅⋅H+−N bond. Quantum chemical calculations reproduce the experimental IRPD spectra and allow to characterize the intramolecular Au⋅⋅⋅H+−N bonding with a short r Au⋅⋅⋅H distance of 2.17 Å and an interaction energy of approximately −10 kcal mol−1. Various theoretical descriptors of chemical bonding calculated for the Au⋅⋅⋅H+−N interaction provide strong evidence for a hydrogen bond of moderate strength.