Ferrer Maxime, Elguero José, Alkorta Ibon, Azofra Luis Miguel
Instituto de Química Médica, CSIC, Juan de La Cierva,3, 28006, Madrid, Spain.
PhD Program in Theoretical Chemistry and Computational Modelling, Doctoral School, Universidad Autónoma de Madrid, 28049, Madrid, Spain.
J Mol Model. 2024 Jun 10;30(7):201. doi: 10.1007/s00894-024-05992-3.
A Conceptual DFT (CDFT) study has been carry out to analyse the coupling reactions of the simplest amine (CHNH), alcohol (CHOH), and thiol (CHSH) compounds with CO to form the corresponding adducts CHNHCOH, CHOCOH, and CHSCOH. The reaction mechanism takes place in a single step comprising two chemical events: nucleophilic attack of the non-metallic heteroatoms to CO followed by hydrogen atom transfer (HAT). According to our calculations, the participation of an additional nucleophilic molecule as HAT assistant entails important decreases in activation electronic energies. In such cases, the formation of a six-membered ring in the transition state (TS) reduces the angular stress with respect to the non-assisted paths, characterised by four-membered ring TSs. Through the analysis of the energy and reaction force profiles along the intrinsic reaction coordinate (IRC), the ratio of structural reorganisation and electronic rearrangement for both activation and relaxation energies has been computed. In addition, the analysis of the electronic chemical potential and reaction electronic flux profiles confirms that the highest electronic activity as well as their changes take place in the TS region. Finally, the distortion/interaction model using an energy decomposition scheme based on the electron density along the reaction coordinate has been carried out and the relative energy gradient (REG) method has been applied to identify the most important components associated to the barriers.
The theoretical calculation were performed with Gaussian-16 scientific program. The B3LYP-D3(BJ)/aug-cc-pVDZ level was used for optimization of the minima and TSs. IRC calculations has also been carried out connecting the TS with the associated minima. Conceptual-DFT (CDFT) calculations have been carried out with the Eyringpy program and in-house code. The distortion/interaction model along the reaction coordinate have used the decomposition scheme of Mandado et al. and the analysis of the importance of each components have been done with the relative energy gradient (REG) method.
开展了一项概念性密度泛函理论（CDFT）研究，以分析最简单的胺（CHNH）、醇（CHOH）和硫醇（CHSH）化合物与CO的偶联反应，形成相应的加合物CHNHCOH、CHOCOH和CHSCOH。反应机理在一个步骤中发生，包括两个化学事件：非金属杂原子对CO的亲核进攻，随后是氢原子转移（HAT）。根据我们的计算，额外的亲核分子作为HAT辅助剂的参与会导致活化电子能显著降低。在这种情况下，过渡态（TS）中六元环的形成相对于以四元环TS为特征的无辅助路径降低了角张力。通过分析沿内禀反应坐标（IRC）的能量和反应力分布，计算了活化能和弛豫能的结构重组与电子重排之比。此外，对电子化学势和反应电子通量分布的分析证实，最高的电子活性及其变化发生在TS区域。最后，使用基于沿反应坐标的电子密度的能量分解方案进行了畸变/相互作用模型，并应用相对能量梯度（REG）方法来识别与势垒相关的最重要成分。
使用高斯-16科学程序进行理论计算。B3LYP-D3(BJ)/aug-cc-pVDZ水平用于优化极小值和TS。还进行了IRC计算，将TS与相关的极小值连接起来。使用Eyringpy程序和内部代码进行了概念性密度泛函理论（CDFT）计算。沿反应坐标的畸变/相互作用模型使用了曼达多等人的分解方案，并使用相对能量梯度（REG）方法对每个成分的重要性进行了分析。
