Silver and thallium ion complexation with allyloxycalix[4]arenes

A series of six calix[4]arene derivatives bearing allyl groups and/or benzy l groups functionalized at the phenolic oxygen atoms were synthesized and t heir cation-binding abilities for silver(I) and thallium(I) ions were evalu ated through solvent extraction experiments. The results showed that both s ilver(I) and thallium(I) picrates were readily extracted by the tetrasubsti tuted p-t-butylcalixarene derivatives, while no extraction of sodium or pot assium picrates was observed. The high extractability of thallium(I) picrat e by these ligands was independent of the functional groups present, but th e extraction of silver picrate seemed to be dependent on the conformational rigidity of the calixarene; those locked into the cone conformation showed the highest extractability for silver picrate.