Forced into proximity: The 4-anilino-5-fluoroquinazoline scaffold is introduced as a model system for the characterization of the weak NH⋅⋅⋅F hydrogen bonding interaction. A combination of experimental (NMR spectroscopy, X-ray crystallography) and theoretical (DFT with NBO, NCI) techniques, together with systematic structural variations, provides insights into the nature of this interaction. Selective modulation of the strength of the intramolecular NH⋅⋅⋅F interaction is demonstrated through electronic substituent effects.

中文翻译：

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一系列 4-Anilino-5-Fluoroquinazolines 中的分子内 N−H⋅⋅⋅F 氢键相互作用：电子和构象效应的实验和理论表征

被迫接近：引入 4-anilino-5-fluoroquinazoline 支架作为模型系统，用于表征弱 NH···F 氢键相互作用。实验（NMR 光谱、X 射线晶体学）和理论（DFT 与 NBO、NCI）技术的结合，以及系统的结构变化，提供了对这种相互作用性质的洞察。通过电子取代基效应证明了分子内 NH···F 相互作用强度的选择性调节。