Dynamics of water interacting with interfaces, molecules, and ions.
Dynamics of water interacting with interfaces, molecules, and ions.
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DOI：
10.1021/ar2000088
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发表时间：
2012-01-17
影响因子：
18.3
通讯作者：
Fayer, Michael D.
中科院分区：
文献类型：
--
作者：
Fayer, Michael D.
水是许多化学过程的重要组成部分，在生物学和地质学等不同领域。水在化学、生物和其他系统中经常出现在非常拥挤的情况下：承压水必须与各种界面和分子基团相互作用，通常在纳米的特征长度尺度上。水在不同环境中的行为是化学系统功能的重要贡献者。在生物学中，水存在于细胞中，在那里它使膜和大的生物分子水合。在地质学中，界面水分子可以控制离子吸附和矿物溶解。嵌入的水分子可以改变沸石的结构。在化学中，水是一种重要的极性溶剂，经常与界面接触，例如在离子交换树脂系统中。水是一个非常小的分子;它的不寻常的性质，其大小是由于形成扩展的氢键网络。水分子的质量和体积与甲烷相似，但甲烷在室温下是气体，熔点和沸点分别为91和112 K。这与水相反，水的熔点和沸点分别为273 K和373 K。不同之处在于，水形成多达四个氢键，具有近似四面体的几何形状。水的氢键网络不是静态的。氢键不断地形成和断裂。在大体积水中，通过氢键的协同形成和解离的氢键随机化的时间尺度约为2皮秒。水的快速氢键重排使得许多在水中发生的过程成为可能，例如蛋白质折叠和离子溶剂化。然而，许多涉及水的过程并不发生在纯的本体水中，并且水的氢键结构动力学可以受到例如界面、离子和大分子的存在的显著影响。在这个帐户中，光谱研究已被用来探索这些影响的细节进行了讨论。由于水分子的重排发生得如此之快，探测水的羟基伸缩模式的超快红外实验在提供有关适当时间尺度上的水动力学的直接信息方面是有用的。利用红外偏振选择泵浦探测实验和二维红外振动回波实验研究了水分子的氢键动力学。水的取向松弛，这需要氢键重排，已被研究在球形界面的离子反胶团和平面界面的层状结构组成的相同的表面活性剂相比。水的取向弛豫在界面处显著减慢。据发现，接口的几何形状是不太重要的比接口的存在。离子的影响被证明是减缓氢键重排。然而，将离子界面与中性界面进行比较表明，界面的化学性质不如界面的存在重要。最后，发现水在有机界面的动力学非常类似于水分子与大聚醚的相互作用。
Water is a critical component of many chemical processes, in fields as diverse as biology and geology. Water in chemical, biological, and other systems frequently occurs in very crowded situations: the confined water must interact with a variety of interfaces and molecular groups, often on a characteristic length scale of nanometers. Water's behavior in diverse environments is an important contributor to the functioning of chemical systems. In biology, water is found in cells, where it hydrates membranes and large biomolecules. In geology, interfacial water molecules can control ion adsorption and mineral dissolution. Embedded water molecules can change the structure of zeolites. In chemistry, water is an important polar solvent that is often in contact with interfaces, for example, in ion-exchange resin systems. Water is a very small molecule; its unusual properties for its size are attributable to the formation of extended hydrogen bond networks. A water molecule is similar in mass and volume to methane, but methane is a gas at room temperature, with melting and boiling points of 91 and 112 K, respectively. This is in contrast to water, with melting and boiling points of 273 and 373 K, respectively. The difference is that water forms up to four hydrogen bonds with approximately tetrahedral geometry. Water's hydrogen bond network is not static. Hydrogen bonds are constantly forming and breaking. In bulk water, the time scale for hydrogen bond randomization through concerted formation and dissociation of hydrogen bonds is approximately two picoseconds. Water's rapid hydrogen bond rearrangement makes possible many of the processes that occur in water, such as protein folding and ion solvation. However, many processes involving water do not take place in pure bulk water, and water's hydrogen bond structural dynamics can be substantially influenced by the presence of, for example, interfaces, ions, and large molecules. In this Account, spectroscopic studies that have been used to explore the details of these influences are discussed. Because rearrangements of water molecules occur so quickly, ultrafast infrared experiments that probe water's hydroxyl stretching mode are useful in providing direct information about water dynamics on the appropriate time scales. Infrared polarization-selective pump-probe experiments and two-dimensional infrared (2D IR) vibrational echo experiments have been used to study the hydrogen bond dynamics of water. Water orientational relaxation, which requires hydrogen bond rearrangements, has been studied at spherical interfaces of ionic reverse micelles and compared to planar interfaces of lamellar structures composed of the same surfactants. Water orientational relaxation slows considerably at interfaces. It is found that the geometry of the interface is less important than the presence of the interface. The influence of ions is shown to slow hydrogen bond rearrangements. However, comparing an ionic interface to a neutral interface demonstrates that the chemical nature of the interface is less important than the presence of the interface. Finally, it is found that the dynamics of water at an organic interface is very similar to water molecules interacting with a large polyether.
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DOI：
10.1021/jp902004r
发表时间：
2009-06-25
期刊：
The journal of physical chemistry. B
影响因子：
--
作者：
Moilanen DE;Fenn EE;Wong D;Fayer MD
通讯作者：
Fayer MD
影响因子：
56.9
作者：
Laage, D;Hynes, JT
通讯作者：
Hynes, JT
影响因子：
4.4
作者：
Asbury, JB;Steinel, T;Fayer, MD
通讯作者：
Fayer, MD
影响因子：
3.3
作者：
Cringus, Dan;Bakulin, Artem;Wiersma, Douwe A.
通讯作者：
Wiersma, Douwe A.
影响因子：
9.9
作者：
FONTELL, K
通讯作者：
FONTELL, K