Two salts containing bis(maleonitriledithiolate)nickel(III)/copper(II) anion and substituted benzyltriphenylphosphinium: Syntheses, crystal structures and magnetic properties

Syntheses, crystal structures and magnetic properties of two salts, [FBzTPP][Ni(mnt)2](1) and [FBzTPP]2[Cu(mnt)2](2) ([FBzTPP]+ = 1-(4′-fluorobenzyl)triphenylphosphinium, mnt2− = maleonitriledithiolate), are investigated. In 1, the anions and cations stack into well-segregated columns, and the Ni(III) ions form a 1D alternating chain in a [Ni(mnt)2]− column through intermolecular Ni⋯S and π⋯π interactions with the Ni⋯Ni distances of 3.939, 4.057 and 4.101 Å, and the C–H⋯N hydrogen bonds are found between the [Ni(mnt)2]− anion and the neighboring [FBzTPP]+ cation. The [Cu(mnt)2]2− anions in 2 do not form a column and no weak interactions exist between the anions duo to isolation of the [FBzTPP]+ cations, while C–H⋯F and C–H⋯S hydrogen bonds were found in 2. Magnetic susceptibility measurements in the temperature range 2–300 K show that 1 exhibits a spin–gap transition around 46 K, and antiferromagnetic interaction (θ = −49.0 K) in the high-temperature phase (HT) and spin gap (Δ/kb = 88.2 K) in the low-temperature phase (LT), while 2 shows a very weak antiferromagnetic coupling behavior with θ = −1.33 × 10−2 K.