Rationalization of single-molecule magnet behavior in a three-coordinate Fe(iii) complex with a high-spin state (: S = 5/2)

Here we show that in the perfect trigonal-planar geometry the iron(iii) complex Fe[N(SiMe₃)₂]₃1 simultaneously has a high spin state (S = 5/2) and uniaxial magnetic anisotropy (with a zero-field splitting parameter D = -1.15(2) cm^-1), as revealed by the dc SQUID magnetic susceptibility measurement, high frequency/field electron paramagnetic resonance (HF-EPR) spectroscopy and ab initio theoretical calculations. Moreover, ac magnetization data reveal a dynamic magnetic behavior with an energy barrier for magnetization reversal of 6.91(5) cm^-1, and pulsed high-field magnetization shows a magnetic bistability at low-temperatures. Thus, 1 is confirmed to be a single-molecule magnet.