Crystal structure and conformational diversity of fluorinated alkyl tosylates

Crystal structures of fluorinated alkyl tosylates TsOCH2CF2CHFCF3 and TsOCH2(CF2)(3)CHF2 have been characterized by X-ray diffraction and quantum chemical calculations. The calculations have revealed the stabilization of head-to-tail conformation for TsOCH2CHF-CF2CF3 due to intramolecular F center dot center dot center dot pi and C-H center dot center dot center dot pi interactions. Alternatively, for TsOCH2(CF2)(3)CHF2 these interactions cannot be responsible for the stabilization of head-to-tail con-formation, thus the linear conformation is proved to be more stable.