Shaping solid-state supramolecular cavities: chemically induced accordion-like movement of gamma zirconium phosphate containing polyethylenoxide pillars

The hydrophilic oxygen atoms of polyethylenoxide chains inserted as pillars in γ-zirconium phosphate form hydrogen bonds with the acid groups of the host. As a result the pillars are almost perpendicular to the γ layers. Upon changing the pH level of the supernatant solution the hydrogen bonds are broken and the pillars become almost perpendicular to the layers (shown schematically). Thus there is a reversible enlargement–shortening of the interlayer space.