Mössbauer spectroscopy monitoring the spin transition of a FeII 1D chain with a fluorinated 4-R-1,2,4-triazole

The spin transition properties of [Fe(fletrz)3](BF4)2•2H2O are described. Fletrz (4-(2’-fluoroethyl)-4H-1,2,4-triazole) is a novel fluorine substituted 1,2,4-triazole ligand which forms 1D chain upon self-assembly with FeII ions. This coordination polymer exhibits reversible abrupt thermochromic spin transition that has been probed by SQUID magnetometry, variable temperature 57Fe Mossbauer spectroscopy (77–300 K) and differential scanning calorimetry (100–300 K).