Cover Feature: Unusual Caesium Monensinate A: Crystallographic Evidence for the Formation of Dinuclear Coordination Species in the Solid State (Chem. Eur. J. 18/2025)

The Cover Feature shows the crystal structure of a caesium complex of the polyether ionophorous antibiotic monensin. It features two bridging Cs+ ions trapped in the hydrophilic cavity of two monensinate anions, in contrast to the mononuclear “closed” constructs of the other alkali ions. MD modelling unveils the effect of solvent polarity (methanol vs. chloroform) on monensin cyclization and its ability to form “open”, “semi-open” and “closed” structures with alkali ions, thus explaining the behaviour of the complexes in the two solvents. More information can be found in the Research Article by N. Petkov, I. Pantcheva and co-workers (DOI: 10.1002/chem.202404453).