Iron(II) Spin Crossover Complexes with Branched Long Alkyl Chain

Abstract The bzimpy iron(II) complexes, 1 – 3 , containing branched long alkyl chains were synthesized and characterized in detail. The temperature-dependant magnetic susceptibility of 1 showed gradual spin crossover behavior from low spin to high spin state, while 2 retained only low spin state in the same condition. Interestingly, 3 displayed an abrupt spin transition in temperature range from T 1/2 ↑ = 236 K to T 1/2 ↓ = 230 K with the thermal hysteresis loop about 6 K. The differential scanning calorimetric analysis of 3 revealed two species of liquid crystal phase transitions at 236 K and 351 K, respectively.