A Magneto‐optical Molecular Device: Interplay of Spin Crossover, Luminescence, Photomagnetism, and Photochromism

Abstract

Abstract A bis(pyrazolylpyridyl) ligand, L, containing a central photochromic dithienylethene spacer predictably forms a ferrous [Fe 2 L 3 ] 4+ helicate exhibiting spin crossover (SCO). In solution, the compound [Fe 2 L 3 ](ClO 4 ) 4 ( 1 ) preserves the magnetic properties and is fluorescent. The structure of 1 is photo‐switchable following the reversible ring closure/opening of the central dithienylethene via irradiation with UV/visible light. This photoisomerization switches on and off some emission bands of 1 and provides a means of externally manipulating the magnetic properties of the assembly.