The preferred conformations of a small polyfunctional molecule containing fluorine, chlorine and hydroxyl groups, the 1-chloro-1,1-difluoro-2-pentanol (CDP), were completely elucidated using ¹H, ¹³C and ¹⁹F NMR in three different solvents. While the Cl-C-C-O dihedral angle was asserted using coupling constant data for the diastereotopic fluorines, the Et-C-C-O torsional angle was analyzed by means of ¹H NMR spectra with selective irradiation of the diastereotopic hydrogens and fluorines. In addition, unusual couplings of the hydroxyl hydrogen with a diastereotopic hydrogen and fluorines provided information on the O-H orientation. The behavior of ¹J_C,F when the solvents varied agrees with a weak F⋅⋅⋅HO intramolecular hydrogen bond. These findings were corroborated, and the governing interactions rationalized with the aid of high level CCSD(T) theoretical calculations. Noteworthy, hyperconjugation involving the electron-acceptor σ*_C-Cl orbital drives the conformational equilibrium rather than the fluorine gauche effect.

使用¹ H，¹³ C和¹⁹ F NMR在三种不同的条件下完全阐明了含氟，氯和羟基的多官能小分子1-氯-1,1-二氟-2-戊醇（CDP）的优选构象溶剂。尽管使用非对映异构体氟的偶合常数数据确定了Cl-CCO二面角，但通过¹ H NMR光谱对非对映异构体中的氢和氟进行了选择性照射，对Et-CCO扭转角进行了分析。另外，羟基氢与非对映体氢和氟的不同寻常的偶联提供了关于OH取向的信息。¹ J _C，F的行为当溶剂变化时，表明F⋅⋅⋅HO分子内氢键弱。这些发现得到了证实，并借助高级CCSD（T）理论计算使控制相互作用合理化。值得注意的是，涉及电子受体σ* _C-Cl轨道的超共轭作用会驱动构象平衡，而不是氟絮凝效应。