A novel mixed-valence Ni(mnt)2 salt: synthesis and crystal structure of [Ni(phen)3]2[Ni(mnt)2]3·2DMF (phen ¼ 1,100-phenathroline, mnt ¼ 1,2-dicyanovinylene-1,2-dithiolato, DMF ¼ N,N-dimethylformamide)

Combination of a cationic complex [Ni(phen)3]2þ and an anionic complex [Ni(mnt)2]2 has resulted in a novel mixed-valence complex [Ni(phen)3]2[Ni(mnt)2]3·2DMF (phen ¼ 1,100-phenathroline, mnt ¼ 1,2-dicyanovinylene-1,2-dithiolato, DMF ¼ N,N-dimethylformamide). Its crystal structure consists of two different types of [Ni(mnt)2] units: [Ni(mnt)2]2 and [Ni(mnt)2]22, the arrangement of the [Ni(mnt)2] anion is found to be quite different from segregated stack layers often found for [Ni(mnt)2]-based compounds. Infrared and electronic spectra also confirmed the existence of both [Ni(mnt)2]2 and [Ni(mnt)2]22 units. q 2004 Elsevier B.V. All rights reserved.