Yamanaka Koji, Kameda Yasuo, Amo Yuko, Usuki Takeshi
R&D Center, Organo Corporation, Kawagishi 1-4-9, Toda, Saitama, 335-0015, Japan.
J Phys Chem B. 2007 Oct 4;111(39):11337-41. doi: 10.1021/jp074862z. Epub 2007 Sep 8.
Neutron diffraction measurements on 35Cl/37Cl isotopically substituted anion exchange resins were carried out in order to obtain direct information on the local structure around the chloride ion absorbed in the resin. Structural parameters concerning the first nearest-neighbor interaction of chloride ions were determined through a least-squares fitting procedure of the observed first-order difference function, DeltaCl(Q). It has been revealed that the chloride ion is neighboring an ion exchange group (-CH2(CH3)3N+) with a Cl-...N distance of 3.10(3) A, and simultaneously bonded with 2.4(1) D2O molecules with a Cl-...D distance of 2.25(2) A. The second and third nearest water molecules around Cl- have also been observed. These results indicate that the direct ionic interaction between Cl- and -CH2(CH3)3N+ drastically reduces the number of first-neighbor water molecules around Cl- but enhances the long-distance structuring of the remaining water molecules in the environment surrounded by a hydrophobic polymer matrix.
对35Cl/37Cl同位素取代的阴离子交换树脂进行了中子衍射测量，以便获取有关树脂中吸收的氯离子周围局部结构的直接信息。通过对观察到的一阶差分函数DeltaCl(Q)进行最小二乘拟合程序，确定了与氯离子第一近邻相互作用相关的结构参数。结果表明，氯离子与离子交换基团(-CH2(CH3)3N+)相邻，Cl-...N距离为3.10(3) Å，同时与2.4(1)个D2O分子结合，Cl-...D距离为2.25(2) Å。还观察到了Cl-周围的第二和第三近邻水分子。这些结果表明，Cl-与-CH2(CH3)3N+之间的直接离子相互作用极大地减少了Cl-周围第一近邻水分子的数量，但增强了由疏水聚合物基质包围的环境中其余水分子的长程结构。
