Crystal structures and magnetic properties of linear trinuclear heterometallic complexes based on [(Tp)Fe(CN)3]−

Using [(Tp)Fe(CN)3]− (Tp = hydrotris(pyrazolyl)borate) as a building block, four trinuclear complexes [MII(DMSO)4][(Tp)Fe(CN)3]2 (MII = Co, 1; Ni, 2; Mn, 3; Cu, 4) (DMSO = dimethyl sulfoxide) have been prepared and their structures and magnetic properties have been studied. Complexes 1-4 are isostructural and crystallize, in which each MII ion is coordinated by two [(Tp)Fe(CN)3]− moieties through cyano-bridges in trans positions, resulting in a linear trinuclear structure. The magnetic properties of 1-4 have been investigated in the 2-300 K temperature range. Ferromagnetic coupling occurs in cyano-bridged NiII-NC-FeIII, MnII-NC-FeIII and CuII-NC-FeIII while antiferromagnetic exchange is present between CoII and FeIII ions. The correlations between the structures and the J values are discussed.