Highly selective supramolecular catalyzed allylic alcohol isomerization
Highly selective supramolecular catalyzed allylic alcohol isomerization
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DOI：
10.1021/ja068688o
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发表时间：
2007-03-14
影响因子：
15
通讯作者：
Raymond, Kenneth N.
中科院分区：
文献类型：
--
作者：
Leung, Dennis H.;Bergman, Robert G.;Raymond, Kenneth N.
超分子四面体组装体Na-12[Ga_4L_6]（L = 1，5-bis-catecholamide naphthalene）被发现能选择性地包封适当大小和形状的单阳离子铑配合物。包封在主体的手性环境中直接影响铑客体的对称性，并且可以通过NMR光谱很好地表征。铑配合物对烯丙醇的异构化反应具有催化活性。对包封铑客体的催化活性的研究表明，主体的受限空腔对金属中心的反应性产生强烈的影响。超分子主体防止错误尺寸和形状的基底进入主体腔并与封装的金属中心反应，同时允许正确尺寸的基底容易接近。这些结果表明，金属中心保持在主体的活性位点，而反应物和产物自由和快速地进入主体腔。
A supramolecular tetrahedral assembly Na-12[Ga4L6] (L = 1,5-bis-catecholamide naphthalene) has been found to selectively encapsulate monocationic rhodium complexes of the appropriate size and shape. Encapsulation within the chiral environment of the host directly affects the symmetry of the rhodium guest and can be well characterized by NMR spectroscopy. The rhodium complexes were found to be catalytically active for the isomerization of allylic alcohols. Investigations into the catalytic activity of the encapsulated rhodium guests have shown that the constrained cavity of the host exerts a strong influence on the reactivity at the metal center. The supramolecular host prevents substrates of the wrong size and shape from entering the host cavity and reacting with the encapsulated metal center, while substrates of the correct dimensions are allowed ready access. These results suggest that the metal center remains in the active site of the host while reactants and products freely and rapidly access the host cavity.