磁场中双亲核试剂的反应性：概念性密度泛函理论与电流密度泛函理论的联合研究
Reactivity of Ambident Nucleophiles in Magnetic Fields: a Combined Conceptual DFT and Current-DFT Study
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中文总结 AI 辅助
研究强磁场对双亲核试剂电子结构和反应性的影响，用概念性密度泛函理论与电流密度泛函理论联合研究，发现磁场调制分子极性和福井函数形状，虽保留双亲核亲性，但高场强下局部反应性重分布或使区域选择性变模糊。
中文摘要 AI 辅助
本文以亚硝酸根和硫氰酸根阴离子为典型例子，研究强外部磁场（高达\(0.30 B_0\)）对双亲核试剂电子结构和反应性的影响。通过电流密度泛函理论计算，并借助概念性密度泛函理论描述符，关注不同取向磁场强度增加时电子结构及相关性质的演变。扩展之前对分子的绝热处理以纳入更高自旋态，利用QSym²框架考虑全磁群内相关量子化学量的对称性质，发现磁场对分子极性和福井函数形状有显著调制。尽管如此，\((\textrm{NO}_2)^-\)和\(\textrm{SCN}^-\)的双亲核亲性基本保留，对软亲电试剂在\(\textrm{SCN}^-\)硫端进攻的偏好也存在。但在更高场强下，福井函数变得更弥散，反映外部磁相互作用相对于内部静电力的重要性增加。这种局部反应性的重新分布不仅预测了具有意外几何形状的反应途径，还提出在强场区域区域选择性可能逐渐变得不那么明确的可能性。
英文摘要
The influence of strong external magnetic fields (up to $0.30\,B_0$) on the electronic structure and reactivity of ambident nucleophiles is investigated using the nitrite and thiocyanate anions as prototypical examples. To capture magnetic-field-induced changes in reactivity, current-density-functional theory (current-DFT) calculations are interpreted through conceptual density-functional theory (conceptual DFT) descriptors, namely global hardness and local softness via Fukui functions, focusing on the evolution of the electronic structure and associated properties with increasing field strength in different orientations. By extending our previous adiabatic treatment of molecules to include higher-spin states, in analogy with earlier work on atoms, and by considering the symmetry properties of relevant quantum-chemical quantities within full magnetic groups using the QSym$^2$ framework, we uncover substantial magnetic-field-induced modulations of both molecular polarity and the shape of the Fukui function. Despite these modulations, the ambident nucleophilicity of both $(\textrm{NO}_2)^-$ and $\textrm{SCN}^-$ is largely preserved, as is the preference for attack by soft electrophiles at the sulfur end of $\textrm{SCN}^-$. At higher field strengths, however, the Fukui functions become increasingly diffuse, reflecting the growing importance of external magnetic interactions relative to internal electrostatic forces. The resulting redistribution of local reactivity not only predicts reaction pathways with unexpected geometries but also raises the possibility that regioselectivity may become progressively less well-defined in the strong-field regime.
