Humboldt-Universität zu Berlin - Mathematisch-Naturwissenschaftliche Fakultät - Institut für Chemie

Photochemical Spin-State Switches



Digital data storage relies on the change of a material’s electrical, magnetic, or optical properties between two states, indicating 1 and 0. Smaller units of information storage are an interesting research target, because they could lead to higher-density storage. Molecular organic switches are interesting in this context. However, the switching of spin states in all-organic molecules is challenging.


Oliver Dumele and his team have synthesized an all-organic molecular spin-state switche that can be switched from a diamagnetic to a paramagnetic form.


When the switches were irradiated using an LED light at a temperature of 77 K, the molecules were transformed to their open, diradical, paramagnetic form (pictured on the right). As they warmed up, the reaction was reversed and the molecules returned to their closed form. This was observed using UV/Vis spectroscopy and electron paramagnetic resonance (EPR) spectroscopy. According to the researchers, this type of spin-state switching could be useful to obtain single-molecule magnets for applications in, e.g., spintronics or data storage.


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