Complete solid state photoisomerization of bis(dipyrazolylstyrylpyridine)iron(II) to change magnetic properties

Iron(II) complexes of Z- and E-2,6-di(1H-pyrazol-1-yl)-4-styrylpyridine (Z-2 and E-2, respectively) exhibited visible light photoisomerization from Z-2 to E-2, both in solution and in solid phases. Z-2 occupied the high-spin state over the full temperature range examined, whereas E-2 displayed a spin crossover phenomenon between 100 K and 300 K.