Synthesis and characterisation of a calix[4]pyrrole functional polystyrene via 'click chemistry' and its use in the extraction of halide anion salts

A polystyrene with pendant calix[4]pyrroles was prepared via click reaction strategy. First, a poly(styrene-co-chloromethylstyrene) with approximately 12% of chloro groups was prepared by conventional free radical polymerisation. The chloro groups were then converted to azido groups using NaN₃ in N,N-dimethylformamide. An alkyne-functionalised calix[4]pyrrole was then coupled to the azido-functionalised polystyrene by click chemistry with high efficiency. The resulting polystyrene with pendant calix[4]pyrroles was used to extract fluoride and chloride anions (as their tetrabutylammonium salts) from their aqueous solutions to organic media.