Аннотация:The structures of complexes [CdL1(NCS)2(H2O)2] (I), [Cd(L1)2(H2O)2][CdI4]0.5H2O (II), where L1 is 1,8-bis[(diphenylphosphoryl)methoxy]-3,6-dioxaoctane, and [Cd(μ-L2)I2]n (III), where L2 is 1,3-bis[oxymethyl(diphenylphosphoryl)]propane have been determined by single-crystal X-ray diffraction. The structures of I and II are the first examples of mononuclear cadmium complexes with phosphoryl podand. The structure of III is formed by 1D chains. The synthesis of 2,6-bis[2-(diphenylphosphoryl)- 4-ethylphenoxymethyl]pyridine (L 3 ) is described. The stability constants of complexes of cadmium nitrate with podands L2 and L3 have been determined by spectrophotometric titration in acetonitrile. It has been found that ligand L3 forms in solution not only a 1:1 (M:L) complex (logβ1 = 4.92 ± 0.11) but also a 2:1 binuclear complex (logβ2 = 9.42 ± 0.11), which results in binding of 85.1% of Cd2+ ions at initial reagent concentrations of 0.1 mM. Under the same conditions, podand L2 binds only 37.4% of Cd2+ ions into a 1:1 complex (logβ1 = 3.98 ± 0.21). The ion-selective properties of L1–L3 as active components of polymeric plasticized membranes of ion-selective electrodes have been tested. A high cadmium selectivity of podand L3 has been found, which, apparently, is due to the formation of complexes with high stability constants in solution.
