Developing a Methodology to Obtain New Photoswitchable Fe(II) Spin Crossover Complexes

The pursuit of new functional materials is a current need for the development of new technologies and smart devices. Stimuli-responsive materials can offer the possibilities to combine various functionalities in a single compound. Spin crossover (SCO) compounds belong to one such class of advanced materials, which exhibit a remarkable change in magnetic and optical properties, and are thus lauded as potential candidates for various applications including data storage, display devices, and sensing applications. To realize Anion Driven Light-Induced Spin Change (AD-LISC) at ambient conditions, the authors need a photo-responsive anion which could undergo photo-switching at room temperature in a solid state without requiring large spatial voids for photo-switching. They successfully designed and synthesized a photo-responsive anion, using a sulfonation reaction applied to trans-cinnamic acid to produce para-sulfocinnamic acid (psca). After asserting the photo-properties of psca, the next step toward AD-LISC observation was to combine psca and Fe(II) ions in a single coordination compound.