Synthesis of new proton-ionizable lariat ethers and calix[4]arene ligands for separation of metal cations

A series of novel proton-ionizable dibenzo-22-crown-7 lariat ethers, i.e. sym-(alkyl)dibenzo-22-crown-7-oxyacetic acids, 3-[sym-(alkyl) dibenzo-22-crown-7-oxy]-propanesulfonates, N-trifluoromethanesulfonyl sym-(alkyl)dibenzo-22-crown-7-oxyacetamides and monoethyl sym-[(alkyl)dibenzo-22-crown-7-oxy]-methylphosphonic acids, have been synthesized as part of the systematic investigation of the effect of structural features on the metal cation complexation and selectivity. Also, several series of novel di-ionizable calix[4]arene, i.e. di-ionizable p-tetraallylcalix[4]arene ligands, di-ionizable p-diallylcalix[4]arene ligands, cone di-ionizable p-tert-butylcalix[4]arene-crown-4 ligands, 1,3-alternate di-ionizable p-tert-butyl-calix[4]arene-crown-4 ligands, cone di-ionizable p-tert-butylcalix[4]arene-benzocrown-4 ligands and 1,3-alternate di-ionizable p-tert-butyl-calix[4]arene-benzocrown-4 ligands, have been prepared in an effort to investigate the effect of subtituents, crown size and conformations on metal cation complexation and selectivity.