Clean and efficient syntheses of calix[4]arene modified polymer supports

The syntheses of two polymer supported calix[4]arenes 8 and 9, using TentaG el S NH21 and aminomethyl polystyrene, have been significantly improved by the replacement of thionyl chloride and excessive amounts of solvents with carbodiimide coupling reagents. The new, environmentally friendly route red uces the number of synthetic steps from five to three and achieves a high l oading of calix[4]arene, as shown by attenuated total reflectance infrared spectroscopy (ATR-IR), NMR and solid-state NMR. Furthermore, the extraction efficiencies of uranium and cadmium by these polymer supported calix[4]are nes demonstrate an additional green aspect to the work.