Scientists from the Leibniz Institute of Photonic Technology (Leibniz IPHT) and the Universities of Jena and Ulm have shown that the properties of special iron compounds that absorb light can be influenced by small changes in their chemical structure. These changes affect the so-called second coordination sphere—a region of the molecule that is not directly bound to the iron atom but nevertheless influences its behavior. By adding protons, the iron compounds react differently to the light they absorb.
