二甲醚二聚体中存在的弱的、不恰当的C-O...H-C氢键。

Weak, improper, C-O...H-C hydrogen bonds in the dimethyl ether dimer.

作者信息

Tatamitani Yoshio, Liu Bingxin, Shimada Jun, Ogata Teruhiko, Ottaviani Paolo, Maris Assimo, Caminati Walther, Alonso José L

机构信息

Department of Chemistry, Faculty of Science, Shizuoka University, Ohya, Shizuoka 422-8529 Japan.

出版信息

J Am Chem Soc. 2002 Mar 20;124(11):2739-43. doi: 10.1021/ja0164069.

DOI:10.1021/ja0164069

PMID:11890825

Abstract

The ground-state rotational spectrum of the dimethyl ether dimer, (DME)(2), has been studied by molecular beam Fourier transform microwave and free jet millimeter wave absorption spectroscopies. The molecular beam Fourier transform microwave spectra of the (DME-d(6))(2), (DME-(13)C)(2), (DME-d(6))...(DME), (DME-(13)C)...(DME), and (DME)...(DME-(13)C) isotopomers have also been assigned. The rotational parameters have been interpreted in terms of a C(s) geometry with the two monomers bound by three weak C-H...O hydrogen bonds, each with an average interaction energy of about 1.9 kJ/mol. The experimental data combined with high-level ab initio calculations show this kind of interaction to be improper, blue-shifted hydrogen bonding, with an average shortening of the C-H bonds involved in the hydrogen bonding of 0.0014 A. The length of the C-H...O hydrogen bonds, r(O...H), is in the range 2.52-2.59 A.

摘要

通过分子束傅里叶变换微波光谱法和自由射流毫米波吸收光谱法研究了二甲醚二聚体（DME）₂的基态转动光谱。还对（DME-d₆）₂、（DME-¹³C）₂、（DME-d₆）…（DME）、（DME-¹³C）…（DME）和（DME）…（DME-¹³C）等同位异构体的分子束傅里叶变换微波光谱进行了归属。转动参数已根据具有Cₛ几何结构进行了解释，其中两个单体通过三个弱C-H…O氢键结合，每个氢键的平均相互作用能约为1.9 kJ/mol。实验数据与高水平的从头算计算相结合表明，这种相互作用是一种非正规的、蓝移的氢键，参与氢键的C-H键平均缩短了0.0014 Å。C-H…O氢键的长度r（O…H）在2.52 - 2.59 Å范围内。