离子对大型水性纳米滴中的结水网络的影响
Jeremy T O'Brien1, Evan R Williams
1Department of Chemistry, University of California, Berkeley, California 94720-1460, USA.
Journal of the American Chemical Society
|May 24, 2012
概括
用各种离子研究水性纳米滴,发现离子电荷会影响水分子的键. 多价离子显著改变水的结构,甚至在纳米滴表面.
科学领域:
- 物理化学 物理化学
- 频谱学是一种光谱学.
- 材料科学 材料科学 材料科学
背景情况:
- 了解离子-水相互作用对于各种化学和生物过程至关重要.
- 纳米水滴的行为与散装水有很大不同.
- 光谱方法提供了对分子结构和结合的洞察.
研究的目的:
- 研究不同离子 (SO(4)(2-),I(-),Na(+),Ca(2+),La(3+)) 在纳米滴中的水分子结网络上的作用.
- 分析离子电荷和类型对纳米滴表面水结构的影响.
- 为了确定离子诱导的结构变化传播到表面的程度.
主要方法:
- 集成红外光解离 (IRPD) 光谱法用于探测水性纳米滴 (约250个水分子) 中的键.
- 在延伸区域 (~2800-3800 cm(-1)) 在133 K.记录了光谱.
- 分析的重点是表面水分子的结合和自由基 (OH) 组对应的特征.
主要成果:
- Spectra显示了结合和自由OH组的特征,后者归因于AAD (接受两个,捐赠一个键) 水分子.
- 随着正离子电荷的增加,AAD自由-OH延伸的频率红移,表明了斯塔克效应.
- 单价离子对散装水的结网的影响最小,而多价离子显著改变了它,影响延伸到纳米滴表面.
结论:
- 离子电荷和类型明显影响纳米水滴中的水的结网.
- 由于离子诱导的电场造成的斯塔克效应会影响表面水分子的频率.
- 离子诱导的纳米滴中的结构变化传播到表面,距离离子超过1纳米.
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