Cooperative magnetic behavior of self-assembled iron(II) chelate chain compounds

The magnetic characterization of two different magnetic chain compounds containing the same Schiff base ligand L but different axially coordinated ligands is reported: The spin crossover complex [Fe(L)(HIm)1.80] and the magnetic compound [Fe(L)(MeOH)1.83]. (L=diethyl (E,E)-2,2′-[1,2-phenylenebis(iminomethylidyne)]-bis[3-oxobutanoate], MeOH=methanol, HIm=imidazole.) The compound [Fe(L)(HIm)1.80] displays a cooperative spin crossover phenomenon (high-spin↔low-spin transition) centered at T1/2=330 K, and the high-spin compound [Fe(L)(MeOH)1.83] shows a weak spontaneous magnetization below Tc=9.5 K. Both complexes are chemically connected via strong hydrogen bonds which influences the magnetic properties of both compounds.