A Superior Ionic Conducting Plastic Crystal Near Room Temperature with Electrical Bistability and Magnetic Transition

Multifunctional ionic plastic crystals (IPCs) are a class of unique materials that exhibit a wide range of advanced applications. In this work, we proposed a strategy for the design of multifunctional, superior ion-conducting IPCs with bistability in both magnetic and electric properties, moreover, we successfully prepared and thoroughly characterized such an IPC, [PMPyr][Ni(mnt)₂] (1; PMPyr⁺=N-propyl-N-methylpyrrolidinium, and mnt²⁻=maleonitriledithiolate). Plastic crystal 1 exhibits superior ion conduction near room temperature, and its ion conductivity reaches the order of 10⁻² S cm⁻¹ at 373 K. Remarkably, the crystal-to-plastic crystal transformation results in 1 simultaneously exhibiting electrical bistability and magnetic transition. Our study paves the way for the development of new IPCs with desirable functional properties.