Suitekijuku (Water Drop Institute), Vancouver, BC, Canada V6R 2P5.
J Phys Chem B. 2013 Jan 24;117(3):877-83. doi: 10.1021/jp3082744. Epub 2013 Jan 11.
The effect of tetraethylammonium chloride (TEAC) on H(2)O was investigated by the 1-propanol (1P) probing thermodynamic methodology developed by us earlier. It was found that TEAC is an amphiphile with a small hydrophobic and a dominant hydrophilic contribution. An earlier application of the same 1P-probing methodology to tetramethylammonium chloride (TMAC) indicated that the latter is as hydrophilic as urea without any hydrophobic contribution. The hydrophilic effect of TEAC was found to be about twice stronger than that of TMAC. To investigate further these surprising findings, we applied a new analysis method using the concept of the excess partial molar absorptivity of the solute on the ν(2) + ν(3) combination band of H(2)O in the near-infrared (NIR) range of their aqueous solutions. The results confirmed that both salts are indeed strongly hydrophilic toward H(2)O which manifests itself in the 5123 cm(-1) chromophore of the NIR band of H(2)O. Furthermore, we suggest from the behavior of the 5263 cm(-1) band that both solutes might form small aggregates in the H(2)O-rich region of the respective aqueous solutions.
我们早前开发的 1-丙醇（1P）探测热力学方法研究了四乙基氯化铵（TEAC）对 H₂O 的影响。结果发现，TEAC 是一种具有较小疏水性和主导亲水性贡献的两亲分子。早先应用相同的 1P 探测方法研究四甲基氯化铵（TMAC）表明，后者与尿素一样亲水，没有任何疏水性贡献。TEAC 的亲水性效应被发现比 TMAC 强约两倍。为了进一步研究这些令人惊讶的发现，我们使用在近红外（NIR）范围内 H₂O 的 ν₂ + ν₃ 组合带的溶质过剩偏摩尔吸光度的概念，应用了一种新的分析方法。结果证实，这两种盐确实对 H₂O 具有很强的亲水性，这在 H₂O 的 NIR 带的 5123 cm⁻¹发色团中表现出来。此外，我们从 5263 cm⁻¹ 带的行为中推断，两种溶质在各自水溶液的富 H₂O 区域可能形成小聚集体。
