质子结合的同质体:结合能与质子亲和关系有什么关系?
Bun Chan1, Janet E Del Bene, Leo Radom
1School of Chemistry and Centre of Excellence in Free Radical Chemistry and Biotechnology, University of Sydney, Sydney, NSW 2006, Australia. chan_b@chem.usyd.edu.au
Journal of the American Chemical Society
|September 20, 2007
概括
质子分子的结合能量取决于质子亲和力. 由于相互竞争的质子和脱质子效应,在中间质子亲和度发生最大的结合.
科学领域:
- 计算化学计算化学
- 物理化学 物理化学
- 量子化学 是一个量子化学.
背景情况:
- 质子亲和力 (PA) 是一种影响分子相互作用的基本特性.
- 质子化同极体 ([X...H-X]+) 对于理解酸化学和溶解非常重要.
- 在这些系统中,结合能 (BE) 和聚合能 (PA) 之间的关系需要详细的研究.
研究的目的:
- 为了研究结合能 (BE) 和质子亲和力 (PA) 在质子同位体中之间的关系.
- 阐明控制质子物种结合能量的因素.
- 了解质子化和脱质子化能量之间的相互作用.
主要方法:
- 高层次的量子化学计算,特别是G3 (((MP2) -RAD//MP2/6-31+G ((d,p).
- 对各种质子型同极体序列的结合能 (BE) 的分析.
- 在BE和质子亲和力 (PA) 之间的相关性分析.
主要成果:
- 对于密切相关的基质,观察到结合能 (BE) 和质子亲和力 (PA) 之间的二次关系.
- 绑定能量最初随PA增加,达到最大值,然后减少.
- 这种行为是由外热部分质子和内热部分脱质子之间的平衡解释的.
结论:
- 质子同质体中的结合能量并不单调地依赖于质子亲和力.
- 最大的结合发生在中间质子亲和度.
- 相互竞争的质子和去质子能量决定了观察到的BE-PA相关性.
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