High-Temperature Quantum Tunneling and Hydrogen Bonding Rearrangements Characterize the Solid-Solid Phase Transitions in a Phosphonium-Based Protic Ionic Liquid.

ABSTRACT: We report the complex phase behavior of the glass forming protic ionic liquid (PIL) d3-octylphosphonium bis(trifluoromethylsulfonyl)imide [C₈ H₁₇ PD₃ ][NTf₂ ] by means of solid-state NMR spectroscopy. Combined line shape and spin relaxation studies of the deuterons in the PD₃ group of the octylphosphonium cation allow to map and correlate the phase behavior for a broad temperature range from 71 K to 343 K. In the solid PIL at 71 K, we observed a static state, characterized by the first deuteron quadrupole coupling constant reported for PD₃ deuterons. A transition enthalpy of about 12 kJ mol^-1 from the static to the mobile state with increasing temperature suggests the breaking of a weak, charge-enhanced hydrogen b

SUBMITTER: Khudozhitkov AE 

PROVIDER: S-EPMC9311734 | biostudies-literature | 2022 Apr

REPOSITORIES: biostudies-literature