Three ion-pair complexes containing bis(maleonitriledithiolate)copper(II) anion and substituted 4-dimethylaminopyridinium: Syntheses, crystal structures, and magnetic properties

Three ion-pair complexes, [4RBzDMAP]2[Cu(mnt)2] (mnt2− = maleonitriledithiolate; [4RBzDMAP]+ = 1-(4′-R-benzyl)-4-dimethylaminopyridinium, R = F(1), Cl(2) and Br(2), form a 3D network structure via C-H···Cu, C-H···N, C-H···S, C-H···π or π···π interactions. It is interesting that 1 and 2 exhibits antiferromagnetic coupling, while 3 shows a weak ferromagnetic coupling feature.