通过水素结合囊的结晶来分离离子的选择性原理
Radu Custelcean1, Aurelien Bock, Bruce A Moyer
1Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA. custelceanr@ornl.gov
Journal of the American Chemical Society
|May 5, 2010
概括
结合囊中的阳离子选择性是由阳离子形状和协调几何学决定的. 硫酸四面体和酸离子由于在囊腔内互补的适合性而表现出高亲和力.
科学领域:
- 超分子化学 超分子化学
- 晶体学 晶体学是指结晶学.
- 材料科学 材料科学 材料科学
背景情况:
- 结合囊是超分子结构,在宿主-客人化学中具有潜在的应用.
- 控制这些囊中的离子选择性对于设计功能性材料至关重要.
- 之前的研究已经探讨了影响客结合的因素,但需要对结晶中的离子选择性的全面分析.
研究的目的:
- 研究控制离子选择性的基本因素,在结合囊的结晶过程中.
- 将热力学测量和结构数据关联起来,以了解观察到的选择性趋势.
- 阐明和在不同离子的结晶过程中的相互作用.
主要方法:
- 溶液和固态热力学测量.
- 阳离子竞争结晶的实验.
- 对等态复合体的X射线晶体分析.
主要成果:
- 研究的复合体 (1a-d) 的晶体结构是同型的,可以直接比较阳离子效应.
- 溶解度顺序 (1a < 1b < 1c < 1d) 与四面体硫酸盐 (SO4(2-)) 和酸盐 (SeO4(2-)) 离子的选择性相关.
- 外热结晶度 (ΔH(水晶) °) 表明硫酸盐和酸盐由于与囊腔的形状互补性而具有有利的相互作用;硫酸盐 (SO3(2-)) 由于不适合而表现出不太有利的度.
结论:
- 这些结囊中的阳离子选择性主要取决于阳离子与囊内部腔之间的几何适合.
- 热力学参数,特别是结晶的度,提供了对宿主-客人相互作用的强度和性质的见解.
- 虽然形状的互补性有利于四面体离子,但硫酸盐和酸盐等类似离子之间的固体溶液的形成可以限制选择性.
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