Infrared and Raman bands of phytantriol as markers of hydrogen bonding and interchain interaction

Hydrogen bonding and interchain interactions in phytantriol, 3,7,11,15-tetramethyl-1,2,3-hexadecanetriol, have been studied by Fourier transform infrared (FT-IR) and Raman spectroscopies. Assignments of the bands were performed based on the OH/OD isotopic substitution, molecular modeling, and measurements of polarized Raman spectra. Marker bands were evaluated from the temperature-dependent spectral changes. It is shown that Raman spectroscopy provides sensitive markers, namely I(δ(CH2))/I(δs(CH3)), τ(CH)2, I(νs(CH3)FR)/I(νs(CH2)), and νs(CH2) for probing the interactions between the hydrocarbon chains. Hydrogen bonding interaction might be studied through the difference Raman spectroscopy by the analysis of polarized band at 811 cm−1. Relationship is found between the frequencies of IR bands at 883-873 and 1097-1086 cm−1, associated with the vibrations localized at the primary COH site, and the frequencies of OH stretching mode, making these bands specific markers in the analysis of hydrogen bonding. Evaluated marker bands may be of utility to probe the interchain and hydrogen bonding interaction of phytantriol with guest molecules in the practically important aqueous liquid-crystalline phases of this lipid.