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Intermolecular hydrogen-bonded structure in aqueous solutions involving amino acid molecules with different optical activities

不同旋光性氨基酸分子水溶液中的分子间氢键结构

基本信息

批准号：
16550049
负责人：
KAMEDA Yasuo
金额：
$ 2.3万
依托单位：
Yamagata University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2005
项目状态：
已结题

项目摘要

Neutron and X-ray diffraction measurements were carried out on aqueous 2.5 mol% DL- and L-alanine solutions in D_2O in order to investigate the difference in intermolecular hydrogen-bonded structure between these solutions involving amino acid molecules with different optical activities. The difference distribution functions Δg(r) derived from the Fourier transform of the difference neutron intermolecular interference function Δi(Q) between DL- and L-alanine solutions exhibited negative peaks at r = 2 and 2.5 Å, these positions correspond to O-H and H-H intermolecular hydrogen-bonded distances, respectively. Quantitative analysis was carried out by means of the least squares fitting analysis of observed Δi(Q). Intermolecular distances and difference coordination numbers obtained were r(O-H)=1.99(3)Å, r(H-H)=2.54Å, Δn(O-H)=-0.031(5), and Δn(H-H)=-0.072(5), respectively. The present values of Δn(O-H) and Δn(H-H) indicate that the intermolecular hydrogen bonds between water molecules in t … More he L-alanine solution are ca.2% stronger than those in the DL-alanine solution. The molecular dynamics simulation was adopted for 2.5 mol% and 1 mol% DL- and L-alanine heavy water solutions. Difference in partial distribution functions for water-water interaction, g_<HH>(r), g_<OH>(r), and g_<OO>(r) does not observed between 1 mol% DL- and L-alanine solutions, implying that the difference in the intermolecular hydrogen-bonded structure between DL- and L-alanine solutions is not present in the diluted condition. On the other hand, the partial distribution functions describing water-water interaction, g_<HH>(r), g_<OH>(r), and g_<OO>(r), obtained for 2.5 mol% DL- and L-alanine solutions indicated that the intermolecular hydrogen bonds in L-alanine solution are ca.1% stronger than that in the DL-alanine solutions. Time-of-flight neutron diffraction measurements on ^<14>N/^<15>N isotopically substituted aqueous 3 mol% DL- and L-alanine heavy water solutions were carried out in order to investigate the difference in hydrogen-bonds between the amino group within the alanine molecule and the nearest neighbor water molecules. The data analysis is in progress. Less

用中子和X射线衍射方法研究了2.5mol%DL-和L-丙氨酸的D_2O水溶液中不同光学活性氨基酸分子间氢键结构的差异。由DL-丙氨酸和L-丙氨酸溶液的差中子分子间干涉函数Δi（Q）的傅里叶变换得到的差分布函数Δg（r）在r = 2和2.5 μ m处出现负峰，这两个位置分别对应于O-H和H-H分子间氢键距离。用最小二乘拟合法对Δi（Q）进行了定量分析。分子间距离r（O-H）=1.99（3）<$，r（H-H）=2.54 <$，Δn（O-H）=-0.031（5），Δn（H-H）=-0.072（5）。Δn（O-H）和Δn（H-H）的当前值表明，水分子间的分子间氢键在水分子中起着重要的作用。 ...更多信息 L-丙氨酸溶液比DL-丙氨酸溶液中的那些强约2%。采用分子动力学模拟2.5摩尔%和1摩尔%的DL-和L-丙氨酸重水溶液。在1mol%的DL-和L-丙氨酸溶液中，水-水相互作用的偏分布函数g_<HH>（r）、g_<OH>（r）和g_<OO>（r）没有差别，这意味着在稀释条件下DL-和L-丙氨酸溶液之间的分子间氢键结构没有差别。另一方面，2.5mol%DL-和L-丙氨酸溶液中描述水-水相互作用的偏分布函数g_<HH>（r），g_<OH>（r）和g_<OO>（r）表明，L-丙氨酸溶液中的分子间氢键比DL-丙氨酸溶液中的强约1%。为了<14><15>研究丙氨酸分子中的氨基和最近邻的水分子之间的氢键的差异，对^ N/^ N同位素取代的3摩尔% DL-和L-丙氨酸重水水溶液进行了飞行时间中子衍射测量。数据分析正在进行中。少