Investigation of the crystal structures and magnetic features of two bis(dithiolato)nickelate salts with flexible organic cations

Abstract

Two bis(dithiolato)nickel salts with different flexible ammonium counterions, [Et3MeN][Ni(dmit)2] (1) and [(i-Bu)Et3N][Ni(dmit)2] (2) (dmit2− = 2-thioxo-1,3-dithiole-4,5-dithiolate, Et3MeN+ = triethylmethylammonium, (i-Bu)Et3N+ = triethylisobutylammonium), are prepared and identified by powder X-ray diffraction (PXRD) patterns and single-crystal X-ray diffraction. Salt 1 crystallizes in the triclinic space group P − 1 at 293 K. The anions and cations in 1 form alternating layered arrangements along the a-axis direction. Salt 2 belongs to the monoclinic crystal system and space group P21/n. The anions and cations in 2 form separate columnar stacks along bc-plane direction. The neighboring anions are stacked as dimers in the anion columnar stacks of 2. The magnetic features of salts 1 and 2 show 1D alternating spin chain magnetic exchange behavior, and the magnetic experimental data are well fitted through a spin chain magnetic model. The difference in the crystal structures and magnetic properties between the two new salts 1 and 2 fully demonstrates that the magnetic properties are dependent on the alignment of the [Ni(dmit)2]− anions, which are related to the flexible organic cations.