A less common spin-crossover process observed in the six-coordinated model heme complexes

The physicochemical properties of a series of the six-coordinated iron(III) diazaporphyrinate complexes, [Fe(DAzP)L2]± where the axial ligands (L) are DMAP, CN−, HIm, Py, 3-ClPy, 4-CNPy, 3-CNPy, 3,5-Cl2Py, THF, have been examined by combined analyses of NMR, EPR, Mössbauer spectrometry, and SQUID magnetometry. The solution and solid-state studies clarified that the complexes with 3-ClPy, 4-CNPy, 3-CNPy, 3,5-Cl2Py are in the less common spin-crossover process between S = 3/2 and S = 1/2 during the temperature change.