方法亲和度量:支持催化,有机合成和有机金属和聚合物化学的关键热力学数据
Weam A O Altalhi1,2, Bun Chan3,4, Richard A J O'Hair1
1School of Chemistry and Bio21 Institute of Molecular Science and Biotechnology, The University of Melbourne, Melbourne, Victoria 3010, Australia.
这项研究量化了s和p块元素的甲基亲和力 (MAs),揭示了化学反应的趋势. 计算分析在气相中识别出稳定的甲基离子和潜在可观测的二离子.
科学领域:
- 计算化学的计算化学
- 量子化学 是一个量子化学.
- 有机金属化学 有机金属化学
背景情况:
- 甲基转移反应在格里格纳德反应,交叉合和聚合催化中至关重要.
- 综合的甲基亲和度 (MA) 尺度是不发达的,阻碍了对这些反应的充分理解.
- 需要准确的热力学数据来预测和控制甲基转移过程.
研究的目的:
- 通过计算来确定多种基化s和p块元素的甲基化亲和度 (MAs).
- 为,中性和离子建立全面的MA尺度.
- 评估由此产生的甲基离子和二离子的热力学和运动稳定性.
主要方法:
- 使用B3LYP-D3BJ/def2-TZVP理论水平进行密度函数理论 (DFT) 计算.
- 计算 (MeZ → Z+ + Me-),中性 (MeY- → Y + Me-) 和离子 (MeX2- → X- + Me-) 形成的能量变化 (MAs).
- 测定垂直分离能 (VDE) 以评估离子和二离子的稳定性.
主要成果:
- 产生了广泛的MA尺度,范围从2525.8kJ/mol (F+) 到-820.4kJ/mol (Me4B-).
- 阴离子MA表现出明显的趋势:下降组的减少和跨时期的增加到素.
- 阳离子和二阳离子的稳定性受到高价值的影响;一些二阳离子 (Me4Ca2-, Me4Sr2-, Me4Ba2-, CF3CaF32-) 显示潜在的动力稳定性.
结论:
- 这项研究提供了一份关于甲基胺亲和关系的全面数据集,阐明了周期表中的趋势.
- 大多数计算的甲基离子是热力学稳定的,Me4N-是例外.
- 离子通常不稳定,但在气相中可以观察到特定的性土金属复合物.
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