title: Molecule-ion interaction and its effect on coordination interaction.
abstract: The present work revealed the presence of the molecule-ion interaction between ethylenediaminetetraacetic acid disodium salt (Na(2)H(2)EDTA) and β-cyclodextrin (CD) on the basis of observable changes in crystal patterns and thermal behaviors before and after interaction. Results from electric conductivity measurements confirmed this presence and showed that the extent of the molecule-ion interaction was associated with the concentration of β-CD. More importantly, the molecule-ion interaction led to a decreased coordination interaction of Na(2)H(2)EDTA and copper chloride, and this decrease exhibited a concentration dependence of β-CD. Similar phenomena were also observed in the case of several analogs of Na(2)H(2)EDTA by UV-vis spectroscopy. A possible explanation was proposed on the basis of the hypothesis that there was a competitive relationship between the molecule-ion interaction and the coordination interaction. Further, nuclear magnetic resonance measurements provided important information on the difference in interaction modes of β-CD with H(2)EDTA(2-) and [Cu(EDTA)](2-). We are of the opinion that the results would provide a significant bridge between coordination chemistry and supramolecular chemistry and help us further understand factors related to different interactions in multicomponent systems.
authors.affiliation: Department of Chemistry, University of Science and Technology of China, Hefei 230026, PR China. solexin@ustc.edu.cn
authors.forename: Le Xin
authors.initials: le X
authors.lastname: Song
authors.forename: Shu Zhen
authors.initials: SZ
authors.lastname: Pan
authors.forename: Lin Hong
authors.initials: LH
authors.lastname: Zhu
authors.forename: Mang
authors.initials: M
authors.lastname: Wang
authors.forename: Fang Yun
authors.initials: FY
authors.lastname: Du
authors.forename: Jie
authors.initials: J
authors.lastname: Chen