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    Facilitated transfer of alkali metal ions by a tetraester derivative of thiacalix[4]arene at the liquid-liquid interface
    (WILEY-V C H VERLAG GMBH, 2008) Akgemci, Emine Güler; Bingöl, Haluk; Ersöz, Mustafa; Stibor, Ivan
    The facilitated transfer of alkali metal ions (Na+, K+, Rb+, and Cs+) by 25,26,27,28-tetraetboxycarbonylmethoxy-thiacalix[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+ 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+, K+, and Rb+ ions except for Cs+ ion. In the case of Cs+ a 1:2 (metal: ionophore) complex was obtained from its special electrochemical response to the variation of ligand concentrations in the organic phase. The logarithms of the complex association constants, for facilitated transfer of Na+, K+, Rb+, and Cs+, were estimated as 6.52, 7.75, 7.91 (log beta(1)degrees), and 8.36 (log V), respectively.
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    Synthesis of Flavin-Calix[4]arene Conjugate Derivatives
    (WILEY-V C H VERLAG GMBH, 2011) Sayın, Serkan; Akkuş, Gülderen Uysal; Cibulka, Radek; Stibor, Ivan; Yılmaz, Mustafa
    The synthesis of two new flavin substituted calix[4]arene derivatives, 9 and 10, is described. The first flavin substituted calix[4]arene derivative 9 was synthesized by the reaction of 3-methylalloxazine (5) with 25,27-bis(3-bromopropoxy)-26,28-dihydroxy-5,11,17,23-tetra(tert-butyl) calix[4] arene (4) in high yield (92%). The other derivative 10 was prepared from 3-methylalloxazine-1-acetic acid (7) and 25,27-bis(3-cyanopropoxy)calix[4]arene (3). All new compounds were characterized by a combination of FTIR and H-1-NMR spectroscopy, and elemental-analysis techniques.