• DOI:10.1039/c5dt00263j
• Corpus ID: 34193230

Crystal structures, phase transitions, and switchable dielectric behaviors: comparison of a series of N-heterocyclic ammonium perchlorates.

@article{Shi2015CrystalSP,
  title={Crystal structures, phase transitions, and switchable dielectric behaviors: comparison of a series of N-heterocyclic ammonium perchlorates.},
  author={Pingping Shi and Qiong Ye and Qiang Li and Hui‐Ting Wang and Dawei Fu and Yi Zhang and Ren‐Gen Xiong},
  journal={Dalton transactions},
  year={2015},
  volume={44 17},
  pages={
          8221-31
        }
}

• P. Shi, Qiong Ye, +4 authors R. Xiong
• Published 23 April 2015
• Chemistry
• Dalton transactions

Three analogue N-heterocyclic complexes, 1-propyl-1-methylpiperidinium perchlorate (, [PMpip][ClO4]), 1-cyanomethyl-1-methylpiperidinium perchlorate (, [CMpip][ClO4]), and 1-cyanomethyl-1-methylmorpholinium perchlorate (, [CMmor][ClO4]) are identified as phase transition materials displaying switchable dielectric behaviors. Despite the common [ClO4](-) anion and the closely related cations, compound crystallizes in the orthorhombic space group P212121, but compounds and belong to the monoclinic space group P21/n with distinct cell dimensions. Compounds , and undergo reversible phase transitions around 199, 387 and 416 K, respectively, accompanied by notable step-like dielectric anomalies which could be switched by the phase transition and be tuned in distinct dielectric states. The respective dielectric constants in the high dielectric states are 1.2, 2.2 and 3.2 times that in the low dielectric states for compounds , and . Generally, these differences in the phase transitions and dielectric properties are caused by the distinct molecular structures and hydrogen-bonding conformations resulting from the structural variations in the side-chain and the ring structure.