The Phase Transitions of 1,4-Dialkyl-1,4-diazoniabicydo[2.2.2]octane Bis(tetrafluoroborate), Cn–DABCO–Cn–(BF4)2 (10≤n≤22)

摘要: The phase transitions of a series title compounds were investigated by means DSC, IR absorption spectra, and measurements ionic conductivities. All the exhibited in range 77–110 °C. spectra clarified that conformational change alkyl chain occurred above transition temperature. temperature dependences conductivities BF4− showed conductivity jumps factor 9–120 around temperatures. A comparison DSC results BF4-salts with those corresponding Br-salts former have higher temperatures, smaller enthalpies (and, accordingly, entropies), values than latter. These show are more rigid low motion group salts is less vigorous latter h...