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平面六配位碳(phC)是碳原子的一种非经典成键方式。目前绝大部分的phC分子都是以B原子作为关键配体。文章以本课题组之前设计的不含硼phC分子D3hCN3Be+3为基础,通过“准等价”替换的方式设计了一系列不含硼的phC分子D3hCN3X+3(X=Si,Ge,Sn,Pb)。电子结构分析表明这些分子内的共价相互作用与静电相互作用都具有夹心键合的特点,这对拉近C-X的距离起到了至关重要的作用,而分子整体的芳香性对保持分子的平面性至关重要,二者的共同作用使phC在这些分子中得以稳定化。分子的电子亲和能按照从Si到Pb的顺序依次减小。这些不含硼的phC分子都有三对与单线态卡宾类似的孤对电子,这使得它们在分子催化领域具有潜在的应用价值。
Planar hexacoordinated carbon (phC) is a non-classical bonding of carbon atoms. At present, most of the phC molecules are based on the B atom as the key ligand. In this paper, we designed a series of non-boron-containing phC molecules D3hCN3X + 3 (X = Si, Ge, Sn, Pb). Electronic structure analysis shows that the covalent and electrostatic interactions in these molecules have the characteristic of sandwich bonding, which plays a crucial role in shortening the distance to CX. The overall aromaticity of the molecule has the effect of keeping the molecular plane Sex is crucial, and the combined effect of the two stabilizes phC in these molecules. The molecular electronic affinities can decrease in order from Si to Pb. These boron-free phC molecules have three pairs of lone pairs of electrons similar to those of the singlet carbene, making them potentially useful in the field of molecular catalysis.