Preparation and First Characterisation of a Pillared γ-Zirconium Phosphate Derivative Containing Dibenzo 18-Crown-6 Groups Covalently Bound to Inorganic Layers

Abstract

A pillared crown ether derivative of γ-zirconium phosphate containing 4,4′-bis(dihydroxyphosphor-y1)dibenzo-18-crown-6 groups covalently bound to inorganic layers has been prepared by a topotactic reaction in 1:1 water-acetone mixture at 80°C. It was found that the original γ-zirconium phosphate was already completely converted into a pillared phase (interlayer distance 1.9 nm) when ∼15% of the interlayer dihydrogen phosphate groups were replaced with 4,4′-bis(dihydroxyphosphoryl)dibenzo-18-crown-6. The interlayer distance of this phase was found to increase progressively up to 2.1 nm with the gradual increase of the replacement to 50%. For higher replacement, a discontinuous transition of this latter phase to a new one (interlayer distance 2.6 nm) was finally observed. Some preliminary computer structural models of the crown ether conformations in the interlayer regions of these pillared phases were derived.

Key Words:

• γ-zirconium phosphate
• γ-zirconium phosphate phosphonates
• 4,4′-bis(dihydroxyphosphoryl)dibenzo-18-crown-6