アルコール中におけるテトラエチルアンモニウムイオンのコンフォメーション平衡に関する研究

抄録

Conformational equilibrium of tetraethylammonium ion (Et₄N⁺) in alcohols (methanol, ethanol, n-propanol) has been investigated by Raman spectroscopy as functions of concentration, pressure and temperature. The difference in the partial molar volume (ΔV^{tg.tg→tt.tt}) between the trans-gauche.trans-gauche (tg.tg) and trans-trans.trans-trans (tt.tt) conformers of Et₄N⁺ ion has been calculated from the pressure dependence of the relative Raman intensity ratio between the conformers. ΔV^{tg.tg→tt.tt} is found to be negative throughout the studied concentration region. The value of ΔV^{tg.tg→tt.tt} is the smallest in the methanol solution. The difference in the partial molar enthalpy (ΔH^{tg.tg→tt.tt}) is also estimated from the temperature dependence of the relative Raman intensity. From these results, we discuss the close relationship between the conformational change and the solvation structure.