The equilibrium between keto and enol forms in acetylacetone and its derivatives is studied using electron delocalization indices and delocalization tensor density. We demonstrate how electron delocalization governs the equilibrium between keto and enol forms. The less stable enols have more distinct double and single bond character in the CCC fragment, while electron delocalization in this fragment is more pronounced in more stable enols. Looking for the origin of such behavior, we considered the one-electron potentials entering the Euler equation for the electron density. We found that electron delocalization is mainly governed by the static exchange potential, which depends on the three-dimensional atomic structure. It, however, does not distinguish differences in electron delocalization in more and less stable enols, the effect arising from the kinetic exchange contribution, which reflects spin-dependent effects in the electron motion. The local depletion of kinetic exchange in the conjugated fragment yields the enhanced electron delocalization along the CCC bonds in more stable enols. Thus, a combination of considered descriptors allowed us to reveal the influence of electron delocalization on the equilibrium between keto and enol forms and showed the significant features of this phenomenon.

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从电子离域角度看酮-烯醇互变异构

使用电子离域指数和离域张量密度研究乙酰丙酮及其衍生物中酮和烯醇形式之间的平衡。我们展示了电子离域如何控制酮和烯醇形式之间的平衡。不太稳定的烯醇在 CC 中具有更明显的双键和单键特征C 片段，而该片段中的电子离域在更稳定的烯醇中更为明显。寻找这种行为的起源，我们考虑了进入欧拉方程的电子密度的单电子势。我们发现电子离域主要受静态交换势的控制，这取决于三维原子结构。然而，它并没有区分越来越不稳定的烯醇中电子离域的差异，这是由动力学交换贡献引起的，它反映了电子运动中的自旋相关效应。共轭片段中动力学交换的局部消耗产生了沿 CC 增强的电子离域C键在更稳定的烯醇中。因此，考虑到的描述符的组合使我们能够揭示电子离域对酮和烯醇形式之间平衡的影响，并显示出这种现象的显着特征。