Zheng Weixi, Tarr Matthew A
Department of Chemistry, University of New Orleans, New Orleans, LA 70148, USA.
Spectrochim Acta A Mol Biomol Spectrosc. 2006 Dec;65(5):1098-103. doi: 10.1016/j.saa.2006.02.010. Epub 2006 Mar 6.
Recent research has indicated that ternary complexes can be formed among carboxymethyl-beta-cyclodextrin, certain polycyclic aromatic hydrocarbons (PAHs) (e.g. anthracene and 2-naphthol), and Fe(2+) in aqueous solution. The formation of these ternary complexes has been suggested as the reason for improved reaction efficiency in iron catalyzed Fenton degradation (H(2)O(2)+Fe(2+)-->*OH+OH(-)+Fe(3+)) of PAHs and other pollutants. In the present work, several other cyclodextrins were examined to determine their ability to form similar ternary complexes with 2-naphthol and Fe(2+). Fluorescence and NMR techniques were employed in this study. Results showed that hydroxypropyl-beta-cyclodextrin, beta-cyclodextrin, and alpha-cyclodextrin were able to encapsulate 2-naphthol molecules, but their binding with Fe(2+) was weak. On the contrary, sulfated-beta-cyclodextrin has significant binding with Fe(2+), but it showed little inclusion of 2-naphthol molecules. Consequently, none of these four cyclodextrins formed significant amounts of ternary complexes in aqueous solution. The techniques used in this study provide useful methods for assessing the ability of cyclodextrins to form ternary complexes with guest compounds and metal ions.
最近的研究表明，在水溶液中，羧甲基-β-环糊精、某些多环芳烃（PAHs）（如蒽和2-萘酚）与Fe(2+)之间可以形成三元络合物。这些三元络合物的形成被认为是铁催化芬顿降解（H(2)O(2)+Fe(2+)-->*OH+OH(-)+Fe(3+)）PAHs及其他污染物时反应效率提高的原因。在本研究中，对其他几种环糊精进行了检测，以确定它们与2-萘酚和Fe(2+)形成类似三元络合物的能力。本研究采用了荧光和核磁共振技术。结果表明，羟丙基-β-环糊精、β-环糊精和α-环糊精能够包封2-萘酚分子，但它们与Fe(2+)的结合较弱。相反，硫酸化-β-环糊精与Fe(2+)有显著结合，但对2-萘酚分子的包合作用很小。因此，这四种环糊精在水溶液中均未形成大量的三元络合物。本研究中使用的技术为评估环糊精与客体化合物和金属离子形成三元络合物的能力提供了有用的方法。
