FT-IR/NIR Spectroscopic Study of the Hydrogen-Bonding of CH to Water in 1-Fluoroheptane

Abstract The aim of the present study is to investigate how F substitution influences the hydrogen-bonding of the CH to water of an alkane. For this purpose we have comparatively studied the hydrogen bonding of the CH to water of heptane CH3(CH2)5CH3 and 1-fluoroheptane CH2F(CH2)5CH3. The property was analyzed from the separated OH stretching spectra of water dissolved in neat liquids and 1-fluoroheptane solution in heptane as solvent. It has been found that the CH of heptane does not interact with water but the CH of 1-fluoroheptane is hydrogen-bonded as a proton donor to water in the manner of CH⋯OH2. The hydration pattern was supported by the observed effects of hydration on the overtone and combination bands of the CH vibrations of CHCl3, of which the CH acts as a proton donor to water. The present study has spectroscopically shown that the CH, which can be activated by the substitution at the Cα position, of an aliphatic hydrocarbon chain may contribute to the hydrogen-bonding interactions with water in organic and biological materials.