Oe from 2 -350 K (Figures ). The measured T value is 3.50 cm 3 mol -1 K at 350 K, which is significantly higher than the spin-only value for HS Fe(II) ion (S = 2, g = 2.0; T = 3 cm 3 mol -1 K), indicating the presence of magnetic anisotropy in iron(II) center. Upon lowering the temperature, the T value decreases slowly to 254 K and then decreases gradually to reach a plateau in the temperature range of 196 -158 K with a value of 1.71 -1.31 cm 3 mol -1 K, indicating the intermediate phase with HS:LS ratio close to 1:1 (S = 2, g = 2.0; T = 3 cm 3 mol -1 K and S = 0, g = 2.0; T = 0.00 cm 3 mol -1 K). Upon further lowering the temperature, T value decreases abruptly to a value of 0.52 cm 3 mol -1 K at 110 K and then decreases slowly to 0.11 at 50 K, which is slightly higher than the expected value for LS Fe(II) state (S = 0, g = 2.0; T = 0.00 cm 3 mol -1 K). Upon further lowering, the measured T value remains almost constant until 10 K. These values indicate a complete two-step SCO from HS to LS state of complex 1. Accordingly, the T value at 10 K corresponds to less than 4% of the residual HS iron(II) center. The slight decrease of the T values below 10 K might be due to the anisotropy coming from the residual HS iron(II)