N-Methylpyrrolidinium hydrogen tartrate (NMPHT): an above-room-temperature order–disorder molecular switchable dielectric material. Issue 39 (4th May 2017)

• Record Type: Journal Article
• Authors: Zeb, Aurang; Khan, Tariq; Asghar, Muhammad Adnan; Sun, Zhihua; Wu, Zhenyue; Zhao, Sangen; Luo, Junhua
• Is Part Of: RSC advances. Volume 7:Issue 39(2017)
• Page Start: 24368
• Page End: 24373
• Publication Date: 2017-05-04
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c7ra00689f
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : A new above-room-temperature molecular switchable dielectric material, which undergoes a first-order phase transition induced by the order-disorder transformation of cation, has been reported. Abstract : A novel molecular switchable dielectric material N -methylpyrrolidinium hydrogen tartrate (NMPHT ) has been synthesized, which undergoes above room temperature phase transition. Thermal measurements, e.g. differential scanning calorimetry and specific heat, confirm the presence of a phase transition around 317.5 K. The dielectric measurement displays a distinct step-like anomaly around T c, showing two different dielectric states, which reveals thatNMPHT is a switchable dielectric material. The single-crystal X-ray diffraction analyses at variable temperatures demonstrate that the phase transition emerges from the severe disordering of the N -methylpyrrolidinium (NMP) cation, and during the transition the symmetry ofNMPHT is transformed from higher ( C 2/ c ) to lower ( P 21 / n ). These findings will provide a new horizon to design smart dielectric structural phase transition materials by incorporating a flexible NMP based scaffold.