Hirose Hiroaki, Sano Haruyuki, Mizutani Goro, Eguchi Masaru, Ooya Tooru, Yui Nobuhiko
School of Materials Science, Japan Advanced Institute of Science and Technology, Tatsunokuchi, Ishikawa 923-1292, Japan.
Langmuir. 2004 Mar 30;20(7):2852-4. doi: 10.1021/la036354w.
The effect of the mobility of ligands (maltose groups) in the polyrotaxanes (pRXs) on the structure of the surrounding water molecules was investigated. Raman spectra of collective OH stretching vibration of water molecules in aqueous solutions of maltose-pRX conjugates with different alpha-cyclodextrin (alpha-CD) threading on a poly(ethylene glycol) (PEG) chain was measured. The mobility of maltose groups was estimated by measuring the relaxation time T2 of the C1 protons in maltose groups bound on alpha-CD by NMR experiment. A positive correlation between the Raman intensity of the collective band and the relaxation time T2 was obtained. This result indicates that the degree of order of the water clusters is higher as the mobility of maltose groups increases in these conjugate solutions. It is suggested that rapid motion of maltose groups in the pRX conjugate can contribute to preserving ordered structure of the bulk water clusters.
研究了聚轮烷（pRXs）中配体（麦芽糖基团）的流动性对周围水分子结构的影响。测量了麦芽糖 - pRX 共轭物水溶液中，不同α - 环糊精（α - CD）在聚乙二醇（PEG）链上穿线时，水分子集体 OH 伸缩振动的拉曼光谱。通过核磁共振实验测量结合在α - CD 上的麦芽糖基团中 C1 质子的弛豫时间 T2，估算麦芽糖基团的流动性。得到了集体谱带的拉曼强度与弛豫时间 T2 之间的正相关关系。该结果表明，在这些共轭溶液中，随着麦芽糖基团流动性的增加，水簇的有序程度更高。有人提出，pRX 共轭物中麦芽糖基团的快速运动有助于保持大量水簇的有序结构。
