The bond strength and nature of a set of 32 Togni-like reagents have been investigated at the M062X/def2-TZVP(D) level of theory in acetonitrile described with the SMD continuum solvent model, to rationalize the main factors responsible for their thermodynamic stability in different conformations, and trifluoromethylation capabilities. For the assessment of bond strength, we utilized local stretching force constants and associated bond strength orders, complemented with local features of the electron density to access the nature of the bonds. Bond dissociation energies varied from 31.6 to 79.9 kcal/mol depending on the polarizing power of the ligand trans to CF₃. Based on the analysis of the Laplacian of the density, we propose that the charge-shift bond character plays an important role in the stability of the molecules studied, especially for those containing I−O bonds. New insights on the trans influence and on possible ways to fine-tune the stability of these reagents are provided.

中文翻译：

---

将键强度和性质与高价 Togni 型碘化合物的热力学稳定性联系起来

已在 M062X/def2-TZVP(D) 理论水平在用 SMD 连续溶剂模型描述的乙腈中研究了一组 32 种 Togni 样试剂的键强度和性质，以合理化负责其热力学稳定性的主要因素具有不同的构象和三氟甲基化能力。对于键强度的评估，我们利用局部拉伸力常数和相关的键强度顺序，辅以电子密度的局部特征来获取键的性质。键解离能从 31.6 到 79.9 kcal/mol 不等，这取决于配体转移到 CF ₃的极化能力. 基于对密度的拉普拉斯算子的分析，我们提出电荷转移键特性在所研究分子的稳定性中起着重要作用，特别是对于那些含有 I-O 键的分子。提供了关于反式影响和微调这些试剂稳定性的可能方法的新见解。