| 新型金属轮烷自组装体系的表征及配位平衡研究 |
| Characterization and Coordination Equlibrium Study on the Self-Assembly System of a New Metallo-Rotaxane |
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| 摘要: 由cucurbituril和精胺盐酸盐生成的类轮烷，与水合烷基钴肟发生自组装反应后，在水溶液中形成了一种新型的金属轮烷。本文通过 1H NMR，ESI-MS，UV-vis方法进行了表征并对该金属轮烷生成的配位反应进行了热力学研究。 |
| 关键词: 金属轮烷 南瓜状化合物 烷基钴肟 自组装 配位平衡 |
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| Abstract: Rotaxane is a kind of interesting supramolecular assemblies that consists of a macrocyclic wheel， a threading molecular axle and two attached stoppers. Mostly， the stoppers are organic groups with big hindrance to prevent the components of a rotaxane from disassembly. In this study， we report a new metallo-rotaxane(s) at which spermine tetrahydrochloride (Sp) threaded the cucurbituril， which is a highly symmetrical cage compound with an exceptional capacity to encapsulate alkylam-monium ions ， and different kinds of aqua(alkyl)cobaloximes (RCo(Hdmg)2H2O) as the two stoppers. The rotax-anes were characterized by 1H NMR and ESI-MS analyses. It is interesting to note that chemical shifts of Sp and cobaloxime are mostly moving to upfield after forming rotaxane. The assignment of Sp in rotaxane was based on the 2D COSY study. The ESI-MS spectrum for R=methyl showed that the peak m/e=904 is the whole matel-lo-rotaxane with two positive charges. Furthermore， we determined the equilibrium constants K(T) and thermodynamic parameters in aqueous so-lution between the pseudorotaxane and aqua(methyl)cobaloxime by UV/Vis spectroscopy. The K(T)， at different temperatures are： 1.88×103(278K); 1.68×103(283K); 1.36×103(288K); 1.16×103(293K); 1.02×103(298K); 8.78×102(303K)， respectively. And from the plot of RlnK against 1/T， we can calculate the changes of the enthalpy (ΔH=-21.6kJ·mol-1) and the entropy (ΔS=-14.8J·mol·K-1) for the coordina-tive reaction. In short， we have shown a new self-assemble metallo-rotaxane in aqueous solution whose most remarkable character is using coordinative compounds as stoppers that includes metal-carbon bond. Such rotaxanes might have interesting optical， electrical or catalytic properties and further investigations are in progress. |
| Keywords: metallo-rotaxane cucurbituril alkylcobaloxime self-assembly coordination equilibrium |
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| 何旭阳,李婧,高燕,陈慧兰.新型金属轮烷自组装体系的表征及配位平衡研究[J].无机化学学报,2003,19(2):153-158. |
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