Synthesis, crystal structures and magnetic properties of three complexes containing bis(maleonitriledithiolate) copper(II) anion and meta-substituted benzyl isoquinolinium cations

Abstract

Three complexes, [3RBzIQl]2[Cu(mnt)2] (mnt2− = maleonitriledithiolate; [3RBzIQl]+ = 1-(3′-R-benzyl)isoquinolinium, R = Cl (1), I (2) or NO2 (3)), have been prepared and characterized by spectroscopic and physicochemical methods as well as by X-ray crystallography. The [Cu(mnt)2]2− anions formed a 1D chain in complex 1, a dimer in 2 and a sheet structure in 3 through C···N and/or N···N interactions. The neighboring dimers of the cations arranged in a boat-type pattern stack into columns through weak π···π, Cl···π or O···π, C–H···π interactions. The anions and cations stack together into a columnar structure with a ···A–CC–A–CC–A··· sequence. The magnetic susceptibilities measured in the temperature range 2.0–300 K reveal that complex 1 undergoes a change from weak ferromagnetic to antiferromagnetic exchange around 132 K, while 2 shows antiferromagnetic behavior and 3 shows a weak ferromagnetic interaction when the temperature is lowered.