Mass spectrometric studies on some F(CF2)n(CH2)mH semifluorinated alkanes

Nine Semifluorinated alkanes, F(CF2)n(CH2)mH, were analysed by electron ionization and electron‐capture mass spectrometry. Both techniques showed the presence of H…︁F bridges between the zigzag hydrocarbon chain and the twisted fluorocarbon one. In particular, this interaction can explain the extensive sequential HF losses detected in electron‐capture mass spectrometry. The low abundance of fragments corresponding to cleavage of a CF2‐CH2 bond indicate a relatively high bond strength.