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

摘要

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, mnt(2) = 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 center dot center dot center dot S and pi center dot center dot center dot pi interactions with the Ni center dot center dot center dot Ni distances of 3.939, 4.057 and 4.101 angstrom, and the C-H center dot center dot center dot 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 center dot center dot center dot F and C-H center dot center dot center dot 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 (theta = -49.0 K) in the high-temperature phase (HT) and spin gap (Delta/k(b) = 88.2 K) in the low-temperature phase (LT), while 2 shows a very weak antiferromagnetic coupling behavior with theta = 1.33 x 10(2) K.

关键词