Bulky aryl functionalized carbazolyl ligands: amido alternatives to the 2,6-diarylphenyl ligand class?
Bulky aryl functionalized carbazolyl ligands: amido alternatives to the 2,6-diarylphenyl ligand class?
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DOI：
10.1039/b716674e
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发表时间：
2008-01
影响因子：
4
通讯作者：
Natalie D. Coombs;A. Stasch;A. Cowley;A. Thompson;S. Aldridge
中科院分区：
文献类型：
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作者：
Natalie D. Coombs;A. Stasch;A. Cowley;A. Thompson;S. Aldridge
基于1,8-二芳基咔唑-9-基骨架的立体负载氨基配体作为电子上不同的替代品被研究用于稳定低配位金属配合物，并首次进行了结构表征。虽然1,8-二苯基咔唑-9-基衍生物很容易获得，但围绕Cipso-Cipso键的快速旋转导致结构上具有特征的主基衍生物{例如。， [(1,8- ph,-3,6- me2c12h4n)K]2}，其中金属中心的配位几何因仲金属芳烃相互作用而增强。相比之下，相应的1,8-二甲基配体中固有的额外体积导致芳烃和咔唑平面基本上垂直排列，以及取代基强制的空间保护口袋。对含有GaCl2片段的配合物的比较结构研究表明，1,8-基卡巴唑-9-基框架比相应的2,6-基苯基配体在金属中心提供更大的空间保护。
Sterically encumbered amido ligands based on a 1,8-diarylcarbazol-9-yl backbone have been investigated as electronically distinct alternatives to the widely-used terphenyl ligand class in the stabilization of low-coordinate metal complexes, and structurally characterized for the first time. While 1,8-diphenylcarbazol-9-yl derivatives are readily available, facile rotation about the Cipso-Cipso bonds leads to structurally characterized main group derivatives {e.g., [(1,8-Ph,-3,6-Me2C12H4N)K]2} in which the coordination geometry at the metal centre is augmented by secondary metal arene interactions. By contrast, the extra bulk inherent in the corresponding 1,8-dimesityl ligand results in essentially perpendicular alignments of the arene and carbazole planes, and a substituent-enforced sterically protected pocket. Comparative structural studies of complexes containing the GaCl2 fragment imply that the 1,8-dimesitylcarbazol-9-yl framework offers greater steric protection at the metal centre than does the corresponding 2,6-dimesitylphenyl ligand.