No abstract

The facilitated transfer of alkali metal ions (Na, and Cs þ ) by 25,26,27,28-tetraethoxycarbonylmethoxythiacalix[4]arene across the water/1,2-dichloroethane interface was investigated by cyclic voltammetry. The dependence of the half-wave transfer potential on the metal and ligand concentrations was used to formulate the stoichiometric ratio and to evaluate the association constants of the complexes formed between ionophore and metal ions. While the facilitated transfer of Li þ ion was not observed across the water/1,2-dichloroethane interface, the facilitated transfers were observed by formation of 1 : 1 (metal:ionophore) complex for Na

No abstract

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.

No abstract