氧化碳 (CO) 的分子轨道n,n = 2-6. 为什么 (CO) 4具有三重基本状态?
Xiaoguang Bao1, Xin Zhou, Charity Flener Lovitt
1Department of Chemistry and the Center for Advanced Scientific Computing and Modeling, University of North Texas, 1155 Union Circle, No. 305070, Denton, Texas 76203-5070, USA.
Journal of the American Chemical Society
|June 13, 2012
概括
循环butan-1,2,3,4-tetrone和相关的碳氧分子表现出独特的基本状态. 轨道交叉解释了偶数的碳氧分子 (如 (CO) 4) 中的三重基态,而奇数的分子仍然是单数的.
科学领域:
- 量子化学 是一个量子化学.
- 计算化学计算化学
- 分子光谱学 分子光谱学
背景情况:
- 碳-氧分子,特别是碳亚氧化物,由于其不寻常的电子结构,引起了人们的兴趣.
- 了解这些分子的基本状态电子配置对于预测它们的反应性和特性至关重要.
研究的目的:
- 调查循环butan-1,2,3,4-tetrone ((CO) 4) 和相关的碳氧寡合物的电子结构和基本状态特性.
- 阐明分子轨道 (MO) 相互作用和轨道交叉在确定这些分子的自旋状态 (单元与三元) 中所起的作用.
主要方法:
- 计算化学方法被用来预测和分析电子结构.
- 分析分子轨道 (MO) 能量和对称性,重点关注C-O π*轨道和碳单对轨道之间的相互作用.
- 在不同的碳氧寡合物 ((CO) n) 中比较电子结构.
主要成果:
- 循环butan-1,2,3,4-tetrone ((CO) 4) 由于单独占据的 b(2g) σ 和 a(2u) π MO,因此具有三重基态.
- 抗结合单对组合和结合π*MO之间的轨道交叉是偶数 (CO) n分子 (n=2,4) 中三重基态的原因.
- (CO) 3和 (CO) 5呈现单个基态,因为这样的轨道交叉不发生.
- 预计 (CO) 6 具有单个基态,与 (CO) 4 不同,原因是非最近邻碳相互作用较弱.
结论:
- 碳氧寡合体的自旋状态是由CO单位数的平价决定的,偶数系统通过轨道交叉倾向于三重基本状态.
- 非近邻相互作用的强度显著影响电子结构和基本状态,如 (CO) 4和 (CO) 6.6之间的差异所示.
- 理论预测为这些有趣的分子的基本电子特性提供了宝贵的见解.
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