Chemistry Institute of Fundamental Sciences, Massey University, Turitea Campus, Private Bag 11 222, Palmerston North, New Zealand 4442.
Inorg Chem. 2013 Apr 1;52(7):3969-75. doi: 10.1021/ic302770t. Epub 2013 Mar 11.
The structures of a series of tetracoordinate beryllium(II) complexes with ligands derived from tertiary-substituted amines have been computationally modeled and their (9)Be 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 (9)Be 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 (9)Be 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).
采用取代基为叔胺的一系列四配位铍（II）配合物的结构已通过计算建模，并使用 6-311++g(2d,p)水平的包含规范原子轨道（GIAO）方法确定其(9)Be 磁屏蔽值。在极性质子溶剂中，与实验值相比，观察到计算的(9)Be NMR 化学位移之间存在良好的相关性，而在极性非质子溶剂中记录的值则不太相关。对许多替代配合物结构进行建模，导致实验与计算（9）Be NMR 化学位移之间的改善，这表明在某些情况下，铍原子并未完全被包裹。一些合成的配合物产生了意想不到的荧光，并且对与电子跃迁相关的计算分子轨道图的检查表明，由于 Be(II)配位时某些构象的锁定赋予的刚性，允许在通过 Be(II)桥接的相邻排列的芳环上离域。
