School of Chemistry and Chemical Engineering, Chongqing University, Daxuecheng South Rd. 55, 401331, Chongqing, China.
Institut für Physikalische Chemie & Elektrochemie, Gottfried-Wilhelm-Leibniz-Universität, Hannover, Callinstr. 3A, 30167 Hannover, Germany.
Phys Chem Chem Phys. 2022 Aug 24;24(33):19919-19926. doi: 10.1039/d2cp02404g.
The rotational spectra of 4-hydroxy-2-butanone and its monohydrate were investigated by Fourier transform microwave spectroscopy complemented by quantum chemical calculations. One conformer of 4-hydroxy-2-butanone, with the intramolecular O-H⋯O hydrogen bond, has been observed in the pulsed jet. Rotational spectra of the six isotopologues (including four C and one O mono-substitution species) in natural abundance were measured and assigned, enabling the accurate structural determination of the molecular skeleton. The most stable isomer of its monohydrate, in which water inserts into the intramolecular hydrogen bond and serves the dual role of being a proton donor and acceptor, was also detected. The rotational spectra of HOD, DOH, DO and HO isotopologues were also measured allowing the accurate evaluation of the parameters of the intermolecular hydrogen bonds. This rotational spectroscopic investigation demonstrates that upon complexation, the weak intramolecular hydrogen bond in the monomer is replaced by two strong intermolecular O-H⋯O hydrogen bonds, leading to a change in the orientation of the -OH group of 4-hydroxy-2-butanone.
通过傅里叶变换微波光谱学与量子化学计算的补充研究，考察了 4-羟基-2-丁酮及其一水合物的转动光谱。在脉冲射流中观察到具有分子内 O-H⋯O 氢键的 4-羟基-2-丁酮的一种构象。测量并分配了天然丰度下的六个同位素（包括四个 C 和一个 O 单取代物种）的转动光谱，从而能够准确确定分子骨架的结构。还检测到其一水合物的最稳定异构体，其中水插入分子内氢键，同时充当质子供体和受体的双重作用。还测量了 HOD、DOH、DO 和 HO 同位素的转动光谱，从而能够准确评估分子间氢键的参数。这项转动光谱研究表明，在络合作用下，单体中较弱的分子内氢键被两个强的分子间 O-H⋯O 氢键取代，导致 4-羟基-2-丁酮的 -OH 基团的取向发生变化。
