The temperature-dependent Mössbauer studies of carbon or MgO-supported Fe(ppi)2(NCS)2 show that the high-spin fraction fhs vs wt% Fe loading plots obtained at 298 K and 78 K have a crossover point (we say the critical size) near 5 wt% Fe size (l0μ size). For the SiO2-supported Fe(2-pic)3Cl2.EtOH (pic=2-picolylamine), the room temperature Mössbauer spectra show that the high-spin fraction decreases steeply with decreasing iron-complex loading.
