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Zeitschrift für Naturforschung A Contents Vol. 69a (2014)

Z. Naturforsch. 69a, 433 – 440 (2014)

doi:10.5560/ZNA.2014-0029

Investigation of New Ionic Plastic Crystals in Tetraalkylammonium Tetrabuthylborate

Tomoyuki Hayasaki¹, Satoru Hirakawa², and Hisashi Honda^1,2

¹Graduate School of Nanobioscience, Yokohama City University, Kanazawa-ku, Yokohama, 236-0027, Japan

²International College of Arts and Sciences, Yokohama City University, Kanazawa-ku, Yokohama, 236-0027, Japan

Received December 24, 2013 / revised March 31, 2014 / published online June 18, 2014

Reprint requests to: H. H.; E-mail: hhonda@yokohama-cu.ac.jp

New plastic crystals of NEt₃PrBBu₄ and NEt₂Pr₂BBu₄ were formed in a new region of ionic plastic crystal. In this area, globular cations and anions are assembled by weak interactions. Differential scanning calorimeter (DSC) measurements of these salts showed a low entropy change of 19.6 and 14.0 J K⁻¹ mol⁻¹ at each melting point, respectively. On the basis of solid-state ¹H and ¹³C nuclear magnetic resonance (NMR) spectra and electrical conductivity measurements, isotropic reorientation and ion transfer of globular cations and anions were detected in these crystals. The other compounds of NEt_xMe_(4−x)BBu₄ (x =1–3) showed tumbling motions and low activation energies of self-diffusion in crystals.

Key words: Plastic Crystal; Ionic Conductor; ¹H MAS NMR; ¹³C MAS NMR.

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