Syntheses, structures and magnetic properties of iron(II) complexes with bulky tridentate ligands

Iron(II) complexes [FeII(dppFc)2](X)2 · n(solv.) (1(X)2 · n(solv.)) (dppFc = 1-ferrocenyl-2-{(2,6-bis(pyrazolyl)pyridyl)-ethylene}, X = I 3 - , BPh 4 - , [Ni(mnt)2]−) were prepared and their magnetic properties were studied. The central iron(II) ion in 1(X)2 · n(solv.) was coordinated by two tridentate ligands, which have redox active ferrocenyl groups. Magnetic susceptibility measurements revealed that the central iron(II) ions in 12+ and in ferrocenes are in high- and low-spin states, respectively, in the temperature range measured.