Structure Switching and Modulation of the Magnetic Properties in Diarylethene‐Bridged Metallosupramolecular Compounds by Controlled Coordination‐Driven Self‐Assembly

: We report three self-assembled iron complexes that comprised an anti-parallel open form (o-Lanti ), a parallel open form (o-Lsyn ), and a closed form (c-L) of diarylethene conformers. Under kinetic control, FeII2 (o-Lanti )3 was isolated, which exhibited a dinuclear structure with diamagnetic properties. Under light-irradiation control, FeII2 (c-L)3 was prepared and exhibited paramagnetism and spin-crossover behaviour. Under thermodynamic control and in the presence of indispensable [FeIII (Tp*)(CN)3 ]- , FeII2 (o-Lanti )3 and FeII2 (c-L)3 transformed into tetranuclear FeIII2 FeII2 (o-Lsyn )2 , which exhibited complete spin-crossover behaviour at T1/2 =353 K.