Abnormal Proton Positioning of Water Framework in the Presence of Paramagnetic Guest within Ion-Doped Clathrate Hydrate Host

The unique host guest interactions of ionic clathrate hydrates, as distinct from those of other nonionic clathrate hydrates, need to be investigated to understand their inherent physicochemical features, but direct observation of ionic host geometry has not yet been attempted. In this study, we first report the distortions of the water-water connection in the charged cages caused by orbital mixing between a paramagnetic guest and an ion-doped host, and by electrostatic repulsion between the cationic host and guest via the direct observation with using synchrotron high-resolution powder diffraction analysis. The present findings well explain the mechanisms of unique phenomena occurring in ionic clathrate hydrates with paramagnetic guests.