Influence of the molecular structures of dithiolate ligands on crystal packing modes and magnetic properties in salts (Bz-Et3N)[Ni(dmit)x(mnt)2−x] (x = 0–2)

Abstract

Nickel-bis-dithiolene salts, (Bz-Et₃N)[Ni(dmit)_x(mnt)_2−x] (x = 0–2 for 1–3 and mnt²⁻ = maleonitriledithiolate, dmit²⁻ = 2-thioxo-1,3-dithiole-4,5-dithiolate), have been prepared and characterized. These three salts exhibit distinct anion packing structures and magnetic properties. [Ni(mnt)₂]⁻ anions, in which the mnt²⁻ ligand has a reduced number of sulfur atoms, form one-dimensional anion stacks in 1. Conversely, [Ni(dmit)₂]⁻ anions, in which the dmit²⁻ ligand contains extended SR groups, give rise to a layered structure in 2; the anion layer is composed of co-facial [Ni(dmit)₂]⁻ dimers, which are interconnected through short lateral-to-lateral S⋯S and head-to-tail S⋯S contacts. The heteroleptic [Ni(dmit)(mnt)]⁻ anions show one-dimensional anion stacking in 3. Charge-assisted H-bonds are formed between the CN groups of the mnt²⁻ ligands and the H atoms of the cations in 1 and 3 and between the terminal S atoms of the dmit²⁻ ligands and the H atoms of the cations in 2. Both 1 and 3 show antiferromagnetic chain behavior. Within the respective magnetic chains, there are much stronger antiferromagnetic interactions in 3 than in 1, and salt 2 shows antiferromagnetic dimer behavior.