Tetradiazo(o-carboxy)phenylcalix[4]arene for Determination of Pb~(2+) Ion

摘要

A new azocalix[4]arene, 5,14,17,23-tetra[(2-benzoic acid)(azo)phenyl] calix[4]arene (2), has been prepared by hydrolysis of its ester derivative and characterized by ~1H NMR, IR, UV-Vis spectroscopy and elemental analysis. Based on UV spectral changes, we found that 2 exhibits Pb~(2+) ion selectivity. In basic media, Pb~(2+) forms a 1:1 complex with the ligand. Beer's law is obeyed in the range of 2.0 X 10~(-6)- 2.4 X 10~(-5) mol L~(-1) of Pb~(2+). The molar absorptivity (epsilon) of 2-Pb~(2+) complex is 1.89 X 10~4 L mol~(-1) cm~(-1) at 440 nm, and the detection limit is 1.6 X 10~(-6) mol L~(-1).