具有高全球变暖潜力 (GWPs) 的循环 perfluorocarbon 基和离子:结构,电子亲和度和振动频率
Partha Pratim Bera1, Lubos Horný, Henry F Schaefer
1Computational Chemistry, University of Georgia, Athens, Georgia 30602, USA.
Journal of the American Chemical Society
|May 27, 2004
概括
循环碳化合物基具有较低的电子亲和力,只有环烯结合电子. perfluorocarbon 激素表现出越来越多的电子亲和力,环的大小高达五个碳,表明它们的化学行为存在显著差异.
科学领域:
- 计算化学是一种计算化学.
- 量子化学是一种量子化学.
- 物理化学 物理化学
背景情况:
- 了解循环碳化合物和高碳基的电子性质对于各种化学应用至关重要.
- 以前的研究已经探讨了这些化合物的反应性和稳定性,但需要对它们的电子亲和力进行系统的比较.
研究的目的:
- 预测小周期性碳化合物和完全化碳基的电电子亲和力,分子几何和振动频率.
- 为了比较碳化合物的电子结合能力与 perfluorocarbon 循环基.
主要方法:
- 使用密度函数理论 (DFT) 方法,包括B3LYP,BLYP和BP86函数.
- 所有计算都使用了双泽塔极化加极化 (DZP++) 基数组.
- 优化的几何形状和激素及其对应的离子的总能量被计算出来.
主要成果:
- 在研究的碳化合物基中,只有环基 (C(3) H(5)) 呈现出正电子亲和力 (0.24 eV).
- perfluorocarbon 激素的电子亲和度显著高,从C(3) F(5) 的2.81 eV增加到C(5) F(9) 的最大3.34 eV,然后对C(6) F(11) 略有下降.
- 对于碳化合物基的电子亲和力通常是负的,这表明相应的阴离子不稳定.
结论:
- 碳化合物循环基通常是较差的电子结合剂,除了环基.
- perfluorocarbon 循环基具有强烈的电子结合倾向,其亲和力受环形大小的影响.
- 该研究强调了替代对循环基的电子性质的重大影响.
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