McLain Sylvia E, Soper Alan K, Luzar Alenka
Spallation Neutron Source and Center for Molecular Biophysics, Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, Tennessee 37831-6475, USA.
J Chem Phys. 2007 Nov 7;127(17):174515. doi: 10.1063/1.2784555.
Aqueous solutions of dimethyl sulfoxide (DMSO) and acetone have been investigated using neutron diffraction augmented with isotopic substitution and empirical potential structure refinement computer simulations. Each solute has been measured at two concentrations-1:20 and 1:2 solute:water mole ratios. At both concentrations for each solute, the tetrahedral hydrogen bonding network of water is largely unperturbed, though the total water molecule coordination number is reduced in the higher 1:2 concentrations. With higher concentrations of acetone, water tends to segregate into clusters, while in higher concentrations of DMSO the present study reconfirms that the structure of the liquid is dominated by DMSO-water interactions. This result may have implications for the highly nonideal behavior observed in the thermodynamic functions for 1:2 DMSO-water solutions.
利用同位素取代增强的中子衍射和经验势结构精修计算机模拟，对二甲亚砜（DMSO）和丙酮的水溶液进行了研究。每种溶质都在两种浓度下进行了测量——溶质与水的摩尔比分别为1:20和1:2。对于每种溶质的两种浓度，水的四面体氢键网络基本未受干扰，尽管在较高的1:2浓度下，水分子的总配位数有所降低。随着丙酮浓度的增加，水倾向于聚集成簇，而在较高浓度的DMSO中，本研究再次证实液体结构主要由DMSO - 水相互作用主导。这一结果可能对1:2 DMSO - 水溶液热力学函数中观察到的高度非理想行为具有启示意义。
