Synthesis and electrochemical properties of calix[4]arene derivatives containing ferrocene units in the cone and 1,3-alternate conformation

Two novel calix[4]arene receptors containing ferrocene units in cone (L1) and 1,3-alternate (L2) conformations have been synthesized from 25,27-dihydroxy-26,28-bis[(3-aminopropyl)oxy]calix[4]arene 4 or 25,26,27,28-tetra[(3-aminopropyl)oxy]calix[4]arene 6 and ferrocenecarboxaldehyde via condensation, respectively. Their structures have been characterized by 1H, 13C, APT, COSY NMR, FTIR, HSMR, and UV-vis spectral data. The electrochemical behavior of L1 and L2 has been investigated in the presence of F−, Cl−, Br−, H2PO4−, CH3COO− anions. Electrochemical studies show that these receptors electrochemically recognize CH3COO−, H2PO4−, and Cl−, anions. Using an UV-vis study, the selectivity to these anions in DMSO solution was confirmed.