Synthesis of new substituted calix[4]arenes and their complexes with iron(III)

The synthesis of new substituted calix[4]arenes was investigated to increase their solubility in organic solvents. It was observed that these compounds cannot be prepared from phenols substituted with strong electron withdrawing substituents (e.g., -CN, -NO2) and phenols which have a p-acidic group (e.g., -OH, -COOH), or a p-carboxylate group (e.g., -COONa). These compounds were treated with some transition metal salts (e.g., FeCl3.6H2O, CuCl2.2H2O, NiCl2.6H2O or COCl2.6H2O). But only Fe(III) gave complexes with the compounds and the complexes have a metal-ligand ratio of 1:1. Elemental analyses, 1H-NMR and IR data of the new compounds are given. It was concluded that these compounds can be used as organic precipitating reactive for iron(III). © 1991, Taylor & Francis Group, LLC. All rights reserved.