title: Comparable strength of OH-O versus OH-π hydrogen bonds in hydrogen-bonded 2,3-benzofuran clusters with water and methanol.
abstract: Two different types of hydrogen bond, which are classified into a familiar OH-O and a relatively weak OH-π one, have been compared in the 1:1 hydrogen-bonded 2,3-benzofuran clusters with water and methanol molecules. By applying fluorescence-detected infrared spectroscopy and dispersed fluorescence spectroscopy, two isomers having different types of hydrogen bonds are distinguished. From the calculated stabilization energy as well as the frequency shift of the OH stretching vibration in each cluster, these two isomers are almost equally stable, although that of OH-π type is usually thought to be relatively weak. It is suggested that the origin of the weak OH-O hydrogen bond is derived from the lower availability for a hydrogen bond acceptor on the oxygen atom of a heteroaromatic ring, which is attributed to the larger furan aromaticity.
authors.affiliation: Department of Chemistry, Graduate School of Science, Fukuoka University, Fukuoka 814-0180, Japan.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Sasaki
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Daicho
authors.forename: Yuji
authors.initials: Y
authors.lastname: Yamada
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Nibu
mesh_terms: D001572:Benzofurans / Q000737:chemistry*; D004583:Electrons; D006860:Hydrogen Bonding; D000432:Methanol / Q000737:chemistry; D008958:Models, Molecular; D010100:Oxygen / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013055:Spectrophotometry, Infrared; D017550:Spectroscopy, Fourier Transform Infrared; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
chemical_list: D001572:Benzofurans; D014867:Water; C105430:benzofuran; D010100:Oxygen; D000432:Methanol