Synthesis and binding properties of two polymeric thiacalix[4]arenes

Two new polymeric thiacalix[4]arenes were synthesized by the reaction of 5,11,17,23-tetra-tert-butyl-25,27-bis[(4-aminobenzyloxy)-26,28-dihydroxy]thiacalix[4]-arene 3 with terephthaloyl dichloride and 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrahydroxy-thiacalix[4]arene 1 with chloromethylated polystyrene (Merrifield's resin). Complexation studies were made by using liquid-liquid and solid-liquid extraction procedures. It was found that the soluble polymeric thiacalix[4]arene derived from terephthaloyl dichloride is better at removing alkali (Li+, Na+, K+, and Cs+) and heavy metal (Cu2+, Cd2+, Hg2+, Pb2+, Co2+ and Ni2+) cations than the precursor thiacalix[4]arenes. Both the soluble polymer and the cross-linked polymer derived from Merrifield's resin are more efficient at removing transition metals from solution than the precursor thiacalix[4]arene.