Iron(II) spin crossover complexes with branched long alkyl chain

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 T1/2↑ = 236 K to T1/2↓ = 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.

The bzimpy iron(II) complexes with branched long alkyl chains were synthesized. They show gradual or abrupt spin crossover behavior from low spin to high spin states and liquid crystal phase transitions.Figure optionsDownload as PowerPoint slideHighlights
► The novel bzimpy iron(II) complexes with branched long alkyl chains. The complexes for synchronization between crystal-mesophase transition and spin crossover behavior. Compound 3 shows abrupt spin transition with the thermal hysteresis.