LAUSR

Abstract The reaction of lithium bis(trifluoromethanesulfonyl)imide with tetraphenylphosphonium bromide in water leads to the formation of tetraphenylphosphonium bis(trifluoromethanesulfonyl)imide ([PPh 4 + ][(CF 3 SO 2 ) 2 N − ]). The obtained compound was identified by means of 1 H, 13 C, 19 F and 31 P NMR spectroscopy. Although it has a structure similar to ionic liquids, it exhibits a melting point above 100 °C. Besides describing the synthesis, a detailed characterization of its conductivity and vibrational spectroscopic properties is presented. For the latter, FT-Raman and FTIR/ATR spectroscopies are used in the wavenumber range from 150 to 3500 cm −1 and from 600 to 3500 cm −1 , respectively. Density functional theory calculations reveal a minor influence of the interionic interactions on the vibrational structure. Consequently, the computational vibrational spectra of the isolated ions show a good agreement with the experimental data. A detailed vibrational assignment is presented. Furthermore, the conductivity data indicate a solid-solid phase transition about 130 K below the melting point.