A Blockwall‐Type Layered Bis(dithiolato)nickelate Radical Salt Exhibiting High‐ and Two‐Dimensional Antiferromagnetic Coupling Feature

Abstract

The family of [M(dmit) 2 ]  salts (dmit 2 = 2-thioxo-1,3-dithiole-4,5-dithiolate; M = Ni, Pd and Pt) generally show novel magnetic, electric, magnetoelectric and photoelectric properties. Herein, a blockwall-type layered [Me 3 S][Ni(dmit) 2 ] radical salt (1; Me 3 S + = trimethylsulfonium) was prepared and characterized by microanalysis, IR spectroscopy, thermal analysis, powder and single crystal X-ray diffraction techniques. Salt 1 crystalizes in triclinic space group P-1, with two pairs of [Ni(dmit) 2 ]  and Me 3 S + ions in an asymmetric unit. The anions form blockwall-type monolayer, being parallel to crystallographic (0 1 1) plane, and the cations are accommodated in the spaces of anion monolayer. Salt 1 features a two-dimensional S = ½ antiferromagnetic (AFM) spin system with  = 97.8(1) K and a semiconductor with σ  10 4 S•cm 1 and activation energy E a = 0.24(1) eV in 308-368 K. 1 shows two-step dielectric relaxations ranged from 173-373 K and 1-10 7 Hz for the dipole motions of two different polar cations. Most importantly, the dielectric constant of 1 reaches to 17, with high- nature. This study suggests the possibility of achieving high- materials by introducing polar and low rotation barrier components into van der Waals crystal and high- [Ni(dmit) 2 ]  -based electrode materials for applications in supercapacitors.