石墨炔结构及性能的理论研究(英文)

Theoretical Study on the Structure and Properties of Graphdiyne

石墨炔作为一种新的稳定的碳同素异形体,由于其独特的结构和性能,预计可广泛地应用于纳米材料及器件中.在本文中,我们采用B3LYP/6-31+G*理论研究了其结构参数、Wiberg键级以及芳香性.计算结果表明,所有的碳原子的p-电子参与形成了非定域的π-键,使得所有C—C键长平均化.苯环的核独立化学位移比乙炔形成的不等边六边形的更负,表明苯环的芳香性更强.该化合物的拓扑性质与Wiberg键级的计算结果也一致.另外,该化合物的LUMO(0.27 eV)带宽大于其HOMO(0.24 eV)的带宽,表明它应该是n-型材料.当采用对称性破缺方法重新对该化合物优化后,计算结果显示该化合物含有3.6个未成对电子,并具有一定的化学反应活性.

The graphdiyne, as a new stable carbon allotrope, is expected to be widely applied to nanosciences and devices due to unique structure and properties. In this paper we investigated the structural parameters, Wiberg bond indices, and the aromaticity of graphdiyne at the B3LYP/6-31 ＋G＊ level. The calculating results indicated all the p-electrons of the carbons were able to form delocalized n-bonds and all the lengths of C---C bonds were to become average. The aromaticity of all the benzene rings was stronger than the scalene hexagon due to more negative the nucleus independent chemical shift （NICS） value. The topological properties of the compound were in good agreement with those discussed in Wiberg Bond Orders. The LUMO bandwidth （0.27 eV） of the title compound was larger than the HOMO bandwidth （0.24 eV）, it indicates that the graphdiyne should be n-type material. The calculation of the odd electrons by the broken symmetry method showed that the compound contains 3.6 effectively unpaired electrons and possesses enhanced chemical reactivity.