Hamid Aabid, Roy Ram Kinkar
Department of Chemistry, Birla Institute of Technology and Science, Pilani 333031, Rajasthan, India.
J Phys Chem A. 2020 Jul 16;124(28):5775-5783. doi: 10.1021/acs.jpca.9b10665. Epub 2020 Jul 6.
The present study tries to validate Hammett's linear free energy relationship through an unconventional approach based on the density functional reactivity theory (DFRT). A kinetic energy component [Δ], derived from the DFRT-based comprehensive decomposition analysis of stabilization energy scheme, is used to verify the linear nature of Hammett's log(/) versus σ plot. The study shows that the [Formula: see text] versus σ plot (where -X is the atom or group substituted in place of -H) is linear in nature (with reasonably high correlation coefficient values) for different series of reactions. The slopes of the plots also reveal the electrophilic or nucleophilic nature of the transition states as is obtained from the conventional log(/) versus σ plot. The study thus establishes that the DFRT-based energy component Δ (which is very easy to compute) can be used, instead of -values, obtained either from the experiment or from computationally intensive conventional thermochemistry calculations to generate reliable Hammett's plot.
本研究试图通过一种基于密度泛函反应理论（DFRT）的非常规方法来验证哈米特线性自由能关系。从基于DFRT的稳定化能方案综合分解分析中导出的动能分量[Δ]，用于验证哈米特log(k/k₀)对σ图的线性性质。研究表明，对于不同系列的反应，[公式：见正文]对σ图（其中-X是取代-H的原子或基团）本质上是线性的（具有相当高的相关系数值）。这些图的斜率也揭示了过渡态的亲电或亲核性质，这与从传统的log(k/k₀)对σ图中得到的结果一致。因此，该研究确定，基于DFRT的能量分量Δ（计算非常容易）可以用来代替从实验中获得的或通过计算密集型传统热化学计算得到的σ值，以生成可靠的哈米特图。
