Zhong Ronglin, Zhang Min, Xu Hongliang, Su Zhongmin
Institute of Functional Material Chemistry & Local United Engineering Lab for Power Battery , Faculty of Chemistry , Northeast Normal University , Changchun 130024 , China . Email:
Chem Sci. 2016 Feb 1;7(2):1028-1032. doi: 10.1039/c5sc03437j. Epub 2015 Oct 27.
Besides the classic double bond scheme, several novel schemes have been proposed to describe the nature of the chemical bond in dicarbon (C), including a quadruple bond and a singlet diradical state. The results from a symmetry-broken CASSCF(8,8)/aug-cc-pVTZ study present a harmony between MO and VB theories, based on the orthogonal hybridization of the 3σ and 2σ orbitals together with the other six pristine valence orbitals. This scheme achieves the same bonding energy, , and one electron density as that from the eight pristine valence orbitals. A quadruple bond scheme, identical to Prof. Shaik's result from VB theory, is achieved with the 4 bond energy in the range of 12.8-27.6 kcal mol. Meanwhile, the weight of a singlet open-shell configuration is the highest among all the possible configurations.
除了经典的双键结构外，还提出了几种新颖的结构来描述二碳（C₂）中化学键的性质，包括四重键和单重态双自由基态。基于3σ和2σ轨道与其他六个原始价轨道的正交杂化，对称性破缺的CASSCF(8,8)/aug-cc-pVTZ研究结果展现了分子轨道（MO）理论和价键（VB）理论之间的一致性。该结构与八个原始价轨道具有相同的键能和单电子密度。通过4个键能在12.8 - 27.6 kcal mol⁻¹范围内实现了与Shaik教授价键理论结果相同的四重键结构。同时，在所有可能的构型中，单重态开壳层构型的权重最高。
