title: Weak, improper, C-O...H-C hydrogen bonds in the dimethyl ether dimer.
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.
authors.affiliation: Department of Chemistry, Faculty of Science, Shizuoka University, Ohya, Shizuoka 422-8529 Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Tatamitani
authors.forename: Bingxin
authors.initials: B
authors.lastname: Liu
authors.forename: Jun
authors.initials: J
authors.lastname: Shimada
authors.forename: Teruhiko
authors.initials: T
authors.lastname: Ogata
authors.forename: Paolo
authors.initials: P
authors.lastname: Ottaviani
authors.forename: Assimo
authors.initials: A
authors.lastname: Maris
authors.forename: Walther
authors.initials: W
authors.lastname: Caminati
authors.forename: José L
authors.initials: JL
authors.lastname: Alonso
mesh_terms: D019281:Dimerization; D005583:Fourier Analysis; D006860:Hydrogen Bonding; D008738:Methyl Ethers / Q000737:chemistry*; D008872:Microwaves; D008968:Molecular Conformation; D013057:Spectrum Analysis / Q000379:methods
chemical_list: D008738:Methyl Ethers; C033413:dimethyl ether