Sensing property and different reactivity of dumbbell-type molecule (1,8-Bis(1-benzimidazolyl)octane) and cyclic-type molecule (1,1′-Tetramethylene- 2,2′-bisbenzimidazole) toward octafluorocyclopentene (C5F8)

[Display omitted] Sensing of octafluorocyclopentene (C5F8) with benzimidazole derivatives, i.e., dumbbell-type molecule (1) (1,8-Bis(1-benzimidazolyl)octane) and cyclic-type molecule (2) (1,1′-Tetramethylene-2,2′-bisbenzimidazole) were studied by UV-Visible, NMR spectroscopic and theoretical analyses from the viewpoint of applications to gas-sensors. Obtained results indicate a moderate reactivity of nucleophilic reactions toward C5F8 in the case of dumbbell-type molecule (1), on the other hand, no reactivity of cyclic-type molecule (2). Theoretical investigations suggest a decrease of electron density of imine group in cyclic-type molecule (2) as compared with that of dumbbell-type molecule (1). Dumbbell-type molecule (1) shows a ppm-level detection of C5F8 by UV-Visible and is not inhibited by inhibitor gases such as perfluorocarbons, ethanol, and vapor acid. The present reaction of molecule (1) will be conducive to a new type of sensing materials for unsaturated fluorocarbons with high sensitivity and selectivity in the field of environmental science and industrial etching process.