CAl4X (X=Si,Ge): molecules with simultaneous planar tetracoordinate carbon, aluminum, and silicon/germanium.
CAl4X (X=Si,Ge): molecules with simultaneous planar tetracoordinate carbon, aluminum, and silicon/germanium.
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DOI：
10.1063/1.2723109
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发表时间：
2007-05
期刊：
影响因子：
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通讯作者：
H. Xie;Yi‐hong Ding
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文献类型：
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作者：
H. Xie;Yi‐hong Ding
作者报告了在 B3LYP/6-311++G(2d)、MP2/6-311++G(2d) 和 CCSD(T)/6-311++G(3df)（单点）水平上对六原子分子 CAl(4)X (X=Si,Ge) 的首次理论研究。三种低位异构体（2.0 kcal/mol 以内）可以形式化地视为由一个 Al+ 与平面 CAl3X- 在侧 Al-X 键 (X-1)、侧 Al-Al 键 (X-2) 和中心 C 原子 (X-3) 相互作用而构成。异构体X-1和X-2均具有平面结构，包括平面四配位碳、铝和硅/锗，而三维异构体X-3具有五配位碳。 X-1和X-2的平面性归因于配体五中心二电子键合分子轨道，类似于负责CAl3X-（X=Si,Ge）平面性的轨道。从动力学上讲，两个平面结构 X-1 和 X-2 可以通过中间体 X-3 轻松地相互转换，表明它们是共存的。特别令人感兴趣的是，据我们所知，异构体 X-1 代表了第一个在单个分子中同时包含三种类型平面中心的例子。三个低位且结构有趣的异构体X-1、X-2和X-3有待未来的实验验证。目前的结果可以丰富平面化学。
The authors report the first theoretical study on the hexa-atomic molecules CAl(4)X (X=Si,Ge) at the B3LYP/6-311++G(2d), MP2/6-311++G(2d), and CCSD(T)/6-311++G(3df) (single point) levels. Three low-lying isomers (within 2.0 kcal/mol) can be formally viewed as constructed by one Al+ interacting with the planar CAl3X- at the side Al-X bond (X-1), side Al-Al bond (X-2), and central C atom (X-3). The isomers X-1 and X-2 both have planar structures that include the planar tetracoordinate carbon, aluminum, and silicon/germanium, while the three-dimensional isomer X-3 has the pentacoordinate carbon. The planarity of X-1 and X-2 is ascribed to the ligand five-center two-electron bonding molecular orbital, similar to the orbital responsible for the planarity of CAl3X- (X=Si,Ge). Kinetically, the two planar structures X-1 and X-2 can be easily interconverted to each other via the intermediate X-3, indicative of their coexistence. Of particular interest, isomer X-1 represents the first example that simultaneously contains three types of planar centers in a single molecule, to the best of our knowledge. The three low-lying and structurally interesting isomers X-1, X-2, and X-3 await future experimental verification. The present results could enrich the planar chemistry.