Synthesis and characterization of a family of Fe(II) tetrazole complexes [Fe(C6mtz)6]X2 (X = BF4¯, ClO4¯, PF6¯) Synthesis and characterization of a family of Fe(II) tetrazole complexes [Fe(C6mtz)6]X2 (X = BF4¯, ClO4¯, PF6¯)

Based on 1-(cyclohexylmethyl)-1H-tetrazole (C6mtz), a series of mononuclear iron(II) spin-crossover complexes with the general formula [Fe(C6mtz)6]X2, where X is the non-coordinating anion (Formula presented.) (1), (Formula presented.) (2), or (Formula presented.) (3), have been synthesized and characterized. Temperature-dependent magnetic susceptibility measurements for 1, 2, and 3 show reversible one-step spin crossover (SCO) behavior between high-spin (HS, S = 2) and low-spin (LS, S = 0) states without hysteresis. The (Formula presented.) compound shows spin transition at T1/2 = 213 K at a considerably higher temperature than the other compounds, (Formula presented.) (T1/2 = 126 K) and (Formula presented.) (T1/2 = 119 K). Temperature-dependent Far-IR and Mössbauer spectra of 2 and 3 were compared with the measured magnetic susceptibility and confirm the one-step SCO behavior of the compounds.