Direct Determination of the Relationship between the Intramolecular Oxygen-Hydrogen Bond Length and Its Stretching Vibrational Frequency of the Methanol Molecule in the Liquid State

Yasuo Kameda; Yuko Amo; Takeshi Usuki; Kazutaka Ikeda; Takashi Honda; Toshiya Otomo

doi:10.1021/acs.jpcb.3c05090

Direct Determination of the Relationship between the Intramolecular Oxygen-Hydrogen Bond Length and Its Stretching Vibrational Frequency of the Methanol Molecule in the Liquid State

J Phys Chem B. 2023 Sep 14;127(36):7758-7763. doi: 10.1021/acs.jpcb.3c05090. Epub 2023 Sep 6.

Authors

Yasuo Kameda¹, Yuko Amo¹, Takeshi Usuki¹, Kazutaka Ikeda², Takashi Honda³, Toshiya Otomo³

Affiliations

¹ Department of Material and Biological Chemistry, Faculty of Science, Yamagata University, 1-4-12, Kojirakawa-machi, Yamagata City, Yamagata 990-8560, Japan.
² Neutron Industrial Application Promotion Center, Comprehensive Research Organization for Science and Society (CROSS), Shirakata, Tokai, Naka, Ibaraki 319-1106, Japan.
³ Institute of Materials Structure Science, KEK, 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan.

PMID: 37671846
DOI: 10.1021/acs.jpcb.3c05090

Abstract

Time-of-flight (TOF) neutron diffraction measurements on pure liquid deuterated methanol and concentrated methanolic LiClO₄ and LiTFSA solutions have been carried out to investigate the effect of intermolecular hydrogen bonds on the intramolecular O-D distance (r_OD) of the methanol molecule in the liquid state. Intramolecular parameters for the methanol molecule are determined by the least-squares fitting analysis of the neutron total interference term observed in the high-Q region. Attenuated total reflection (ATR) IR spectra have been measured for methanolic solutions of natural abundance to determine the gravitational center frequency (ν_OH) of the stretching vibrational band of the methanol molecule. The relationship between r_OD and ν_OH is approximated well by a linear function. The value dν_OH/dr_OD = -17000 ± 3000 cm^-1 Å^-1 has been derived from the slope of the fitted function. It has been revealed that the O-D bond length of the methanol molecule is sensitively affected by the intermolecular hydrogen bonding interaction.