Syntheses, crystal structures and properties of two new ion-pair complexes by self-assembly of bis(maleonitriledithiolate)copper(II)/nickel(III) anion and substituted 4-dimetylaminopyridinium

Two new ion-pair complexes, [ClBrBzPyN(CH3)2]2[Cu(mnt)2](1) and [ClBrBzPyN(CH3)2][Ni(mnt)2](2) have been obtained by self-assembly of the [M(mnt)2]x− (M = Cu(II) or Ni(III), mnt2− = maleonitriledithiolate, x = 1 or 2) anion and [ClBrBzPyN(CH3)2]+ ([ClBrBzPyN(CH3)2]+ = [1-(4′-chloro-2′-bromobenzyl)-4-dimethylaminopyridinium]) cation. The cations in 1 stack into a column through the CH⋯Br hydrogen bonds and the π⋯π stacking interactions, while the [Cu(mnt)2]2− (A) and the cations (C) stack alternately into a 1D column (i.e., of type ⋯CCACCACC⋯). The anions and the cations in 2 stack into segregated columns in which the Ni(III) ions form a uniform 1D zigzag magnetic chain. Magnetic susceptibility measurements in the temperature range 2–300 K show that 1 exhibits an antiferromagnetic coupling feature with θ = −25.3 K, while 2 shows characteristic of spin-gap (Δ/kb = 1044.3 K) around 114 K.