Structural analysis of calix[n]arene-iron(III) complexes (n=4,?6,?8) and thermal decomposition of the parent calix[n]arenes

Abstract

In this study, six new calix[n]arene-Fe3+ complexes (n?=?4,?6,?8) were synthesized with parent calix[n]arenes in a DMF solution of FeCl3?•?H2O. The properties and coordination characteristics of the six parent calix[n]arene-Fe3+ complexes were determined by elemental analyses, TG-DTA, UV-vis, FT-IR and 1H NMR spectroscopy. According to UV-vis analysis, in the six complexes the iron(III) coordinated by oxygen donor atoms from calix[n]arene ligands and DMF molecules. The complexes behave as 1?:?1 and 1?:?2 electrolytes in the case of calix[n]arenes (n?=?4,?6) (1-4) and calix[8]arene (5, 6), respectively. 1H NMR studies demonstrate that 1 and 2 are more stable than 3, 4, 5 and 6 in DMF, and indicate cone conformation of the calix[4]arene ligands (1 and 2).