Multiplicity-driven photochromism controls three-state fulgimide photoswitches.

Fulgimide photoswitches display three-state photoswitching between isomeric forms Z, E and C. Fulgimides have therefore access to both large steric change of double bond isomerization and the large spectral change induced by electrocyclization. By controlling the multiplicity and photoisomerization conditions, we achieved precise and near-quantitative control over both isomerization modes.

Bridging Electrochemistry and Photoelectron Spectroscopy in the Context of Birch Reduction: Detachment Energies and Redox Potentials of Electron, Dielectron, and Benzene Radical Anion in Liquid Ammonia.

Birch reduction is a time-proven way to hydrogenate aromatic hydrocarbons (such as benzene), which relies on the reducing power of electrons released from alkali metals into liquid ammonia. We have succeeded to characterize the key intermediates of the Birch reduction process─the solvated electron and dielectron and the benzene radical anion─using cyclic voltammetry and photoelectron spectroscopy, aided by electronic structure calculations. In this way, we not only quantify the electron binding energies of these species, which are decisive for the mechanism of the reaction, but also use Birch reduction as a case study to directly connect the two seemingly unrelated experimental techniques.