A variable-temperature Q- and X-band EPR study of spin-crossover iron(III) Schiff base complex

The mononuclear iron(III) Schiff base complex was analysed by EPR spectroscopy. The first derivative Q- and X-band EPR spectra of spin-crossover iron(III) complex exhibit the presence of the high spin ( S = 5/2) and low spin ( S = 1/2) iron(III) state. The variable-temperature EPR measurement confirmed a gradual spin-crossover transition ( S = 5/2 ↔ S = 1/2). The possible hysteresis in the thermally induced spin-crossover effect was not detected. The EPR data are in agreement with observed trends in the magnetic measurements reported previously. Note that the EPR studies of this complex have not been performed before. It is obvious that EPR spectroscopy is a powerful method for investigation of the spin-crossover transition and their temperature evolution in the iron(III) complexes.