Perylene salts of unsymmetrical nickel and gold dithiolene complexes with 3 ∶ 2 stoichiometry: conformational polymorphism and strong antiferromagnetic interactions

Abstract

The square-planar Au^III complex of the unsymmetrical tfadt dithiolate ligand (tfadt: 2-(trifluoromethyl)acrylonitrile-1,2-dithiolate) is found to exhibit conformational polymorphism in its n-Bu₄N⁺ salt, as both cis and trans isomers were found to crystallize separately in the same crystallization batch. Electrocrystallization of perylene in the presence of the diamagnetic [n-Bu₄N][Au(tfadt)₂] or the paramagnetic (S = 1/2) [n-Bu₄N][Ni(tfadt)₂] nickel analog affords isostructural salts with an unusual 3 ∶ 2 stoichiometry, that is [Per]₃[M(tfadt)₂]₂ (M = Au, Ni), with an alternation of dicationic [Per]₃²⁺ perylene triads and dianionic [M(tfadt)₂]₂²⁻ dithiolene complex dyads within one-dimensional chains. These salts are characterized by strong antiferromagnetic interactions within perylene triads and [Ni(tfadt)₂]₂²⁻ dyads and an essentially diamagnetic behaviour.