The host-guest complexation reactions between 5,11,17,23-tetra-tert-butyl-25,27-diethoxycarbonylmethoxy-26,28-dimethoxy calix[4]arene (BDDC4) and alkali and alkaline-earth metal ions were investigated by facilitated ion transfer processes across water/1,2-dichloroethane microinterface by using steady-state cyclic voltammetry and differential pulse voltammetry. The obtained facilitated transfers for Li + , Na + , K + , Rb + and Ca 2 + were evaluated under the different experimental conditions, at the excess concentrations of metal ions with respect to BDDC4 and vice versa. The association constants having 1 : 1 stoichiometry for Li + , Na + , K + and Rb + in 1,2-DCE were determined. Also, we demonstrated that BDDC4 can play an important role for the development of highly selective chemical sensor for Ca 2 + among alkaline-metal ions in the concentration range of 0.1-1.0 mM in aqueous solution.

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Synthesis and electrochemical properties of a novel calix[4]arene derivative for facilitated transfer of alkali metal ions across water/1,2-dichloroethane micro-interface, Supramolecular Chemistry, 23:8, 570-578,The alkali metal ion transfers facilitated by a novel calix[4]arene derivative (OPEC) across the water/1,2-dichloroethane (1,2-DCE) micro-interface supported at the tip of a micropipette were presented. The well-defined voltammetric behaviours except Cs þ was obtained by cyclic voltammetry and differential pulse voltammetry. The bulk concentration of metal ions was much higher than that of OPEC in the performed measurements. The diffusion coefficient of OPEC in the 1,2-DCE phase was calculated as 5.18^0.70 £ 10 26 cm 2 s 21 . On the basis of the changes of the half-wave transfer potentials, the logarithms of the association constants having 1:1 ionophore -ion complex stoichiometry for Li þ , Na þ , K þ and Rb þ in 1,2-DCE were determined as 4.80, 4.62, 4.98 and 5.32, respectively. The facilitated ion transfers were also evaluated by the Randles equivalent circuit used for ac-impedance data analysis.