The rotational spectrum of the binary complex formed between 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) and 1,4-dioxane was investigated using a chirped pulse Fourier transform microwave spectrometer. HFIP is known to be an exceptional solvent that catalyzes the epoxidation of olefins by hydrogen peroxide. The addition of 1,4-dioxane can severely reduce HFIP’s ability to boost the epoxidation rate, possibly through its intermolecular interactions with HFIP. It is therefore of considerable interest to examine the non-covalent interactions between HFIP and 1,4-dioxane in detail. Theoretical conformational searches were carried out for the binary HFIP···1,4-dioxane complex and 17 minimum energy structures were identified. Seven of them are within an energy window of 7 kJ mol⁻¹, while the three lowest energy ones are within 1.4 kJ mol⁻¹. Experimentally, only the rotational spectrum of the most stable conformer was detected and assigned. To understand the non-observation of the other low energy conformers in the supersonic jet expansion, subsequent analyses were performed to estimate the conformational conversion barriers. The detected conformer contains a trans HFIP subunit which is hydrogen-bonded to an O atom of 1,4-dioxane and is further stabilized by weak F···H attractive interactions. The intermolecular interactions in HFIP···1,4-dioxane were analyzed and visualized using QTAIM, NCI and SAPT approaches and the interaction energies compared to the HFIP dimer and related complexes of HFIP and 1,4-dioxane with water.

使用a脉冲傅里叶变换微波光谱仪研究了1,1,1,3,3,3-六氟-2-丙醇（HFIP）和1,4-二恶烷之间形成的二元配合物的旋转光谱。已知HFIP是一种特殊的溶剂，可通过过氧化氢催化烯烃的环氧化。1,4-二恶烷的加入可能会严重降低HFIP提高环氧化速率的能力，这可能是由于其与HFIP的分子间相互作用。因此，非常感兴趣的是详细研究HFIP和1,4-二恶烷之间的非共价相互作用。对二元HFIP···1,4-二恶烷配合物进行了理论构象搜索，确定了17个最低能级结构。其中七个在7 kJ mol ^-1的能量窗口内，而三个最低能量在1.4 kJ mol ^-1之内。实验上，仅检测和分配了最稳定构象体的旋转光谱。为了了解在超声速射流扩展中未观察到其他低能构象体，随后进行了分析以估计构象转换障碍。所检测的构象异构体包含反式HFIP亚基，该氢基与氢键合到1,4-二恶烷的O原子上，并通过弱的F···H吸引相互作用进一步稳定。使用QTAIM，NCI和SAPT方法分析并可视化了HFIP···1,4-二恶烷中的分子间相互作用，并将其与HFIP二聚体以及HFIP和1,4-二恶烷与水的相关配合物进行了比较。