Encapsulation of the BeII Cation: Spectroscopic and Computational Study

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• 作者：Karl J. Shaffer ; Ross J. Davidson ; Anthony K. Burrell ; T. Mark McCleskey ; Paul G. Plieger
• 刊名：Inorganic Chemistry
• 出版年：2013
• 出版时间：April 1, 2013
• 年：2013
• 卷：52
• 期：7
• 页码：3969-3975
• 全文大小：320K
• 年卷期：v.52,no.7(April 1, 2013)
• ISSN：1520-510X

文摘

The structures of a series of tetracoordinate beryllium(II) complexes with ligands derived from tertiary-substituted amines have been computationally modeled and their ⁹Be magnetic shielding values determined using the gauge-including atomic orbital (GIAO) method at the 6-311++g(2d,p) level. A good correlation was observed between calculated ⁹Be NMR chemical shifts when compared to experimental values in polar protic solvents, less so for the values recorded in polar aprotic solvents. A number of alternative complex structures were modeled, resulting in an improvement in experimental versus computational ⁹Be NMR chemical shifts, suggesting that in some cases full encapsulation on the beryllium atom was not occurring. Several of the synthesized complexes gave rise to unexpected fluorescence, and inspection of the calculated molecular orbital diagrams associated with the electronic transitions suggested that the rigidity imparted by the locking of certain conformations upon Be^II coordination allowed delocalization across adjacent aligned aromatic rings bridged by Be^II.