Linear trinuclear copper(II) complexes derived from the nucleophilic addition products of dicyanonitrosomethanide [C(CN)(2)(NO)](-): syntheses, structures, and magnetic properties

Two novel trinuclear Cu-II complexes have been synthesised from the nucleophilic addition derivatives of the small cyano anion, dicyanonitrosomethanide (dcnm). The reaction of Cu-II with the water adduct ligand, carbamoylcyanonitrosomethanide (ccnm) and teaH(3) (triethanolamine) in a basic MeOH/MeCN solution results in the formation of [Cu-3(acnm)(2)(teaH(2))(2)]center dot 2MeOH (1) (acnm = amidocarbonyl(cyano)nitrosomethanide and teaH(2)(-) = singly deprotonated triethanolamine). The reaction of Cu-II with dicyanonitrosomethanide (dcnm) and m-xylenediamine in a basic MeOH/MeCN solution results in the formation of [Cu-3(cimm)(2)(a3acnm)(2)]center dot 6MeCN (2) (cimm = cyano(imido(methoxy) methyl) nitrosomethanide and a3acnm = amino(3-aminomethylphenyl)methylimino methyl(cyanonitrosomethanide)). Both complexes display linear trinuclear Cu-II metallic cores. Solid state DC magnetic susceptibility studies were performed on 1 and 2. Compound 1 revealed very strong antiferromagnetic interactions between central and terminal Cu atoms, while compound 2 displayed ferromagnetic interactions because of the orthogonal relationship of the terminal Cu(d(x2-y2)) and the central Cu(d(x2-y2)) magnetic orbitals, which contrasts with these orbitals being coplanar in 1 thus providing strong superexchange pathways involving Cu-N-O-Cu moieties.