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.