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短氢键的性质和化学键存在一定的交叉
作者:小柯机器人 发布时间:2021/1/9 22:05:09

美国芝加哥大学的Andrei Tokmakoff课题组近日取得一项新成果。通过光谱学手段,他们的最新研究提出,短氢键的性质和化学键存在一定的交叉。该项研究成果发表在2021年1月8日出版的《科学》上。

氢键可被认为是一种经典的静电相互作用,但在相互作用较强时也可看做是一种共价化学键。因此,短而强的氢键作为两种定性不同的描述性成键方式的交叉点存在着,但鲜有了解这一以二分法定义的成键方式的实验。[F-H-F]-离子代表着一类裸露的短氢键,其在水溶液中特殊的振动势能可以通过飞秒二维红外光谱得以揭示。[F-H-F]-的光谱表现出质子运动的超谐行为,并与供体-受体伸缩相耦合,在氢键弯曲时消失。

通过与高水平量子化学计算相结合,研究人员展示了传统氢键向短强氢键过渡时光谱性质的明显转变,此即氢键消失、化学键开始的临界点。

附:英文原文

Title: Crossover from hydrogen to chemical bonding

Author: Bogdan Dereka, Qi Yu, Nicholas H. C. Lewis, William B. Carpenter, Joel M. Bowman, Andrei Tokmakoff

Issue&Volume: 2021/01/08

Abstract: Hydrogen bonds (H-bonds) can be interpreted as a classical electrostatic interaction or as a covalent chemical bond if the interaction is strong enough. As a result, short strong H-bonds exist at an intersection between qualitatively different bonding descriptions, with few experimental methods to understand this dichotomy. The [F-H-F] ion represents a bare short H-bond, whose distinctive vibrational potential in water is revealed with femtosecond two-dimensional infrared spectroscopy. It shows the superharmonic behavior of the proton motion, which is strongly coupled to the donor-acceptor stretching and disappears on H-bond bending. In combination with high-level quantum-chemical calculations, we demonstrate a distinct crossover in spectroscopic properties from conventional to short strong H-bonds, which identify where hydrogen bonding ends and chemical bonding begins.

DOI: 10.1126/science.abe1951

Source: https://science.sciencemag.org/content/371/6525/160

期刊信息

Science:《科学》,创刊于1880年。隶属于美国科学促进会,最新IF:41.845
官方网址:https://www.sciencemag.org/
投稿链接:https://cts.sciencemag.org/scc/#/login