Chloroselenates with Di- and tetravalent selenium: Se-77-NMR-spectra, syntheses, and crystal structures of (PPh4)(2)SeCl6 center dot 2CH(2)Cl(2), (NMe3Ph)(2)SeCl6, (K-18-crown-6)(2)SeCl6 center dot 2CH(3)CN, PPh4Se2Cl9, (NEt4)(2)Se2Cl10, (PPh4)(2)Se3

摘要

The title compounds were obtained from reactions of selenium and selenium tetrachloride with PPh4Cl, NEt4Cl, NMe3PhCl, or (K-18-crown-6)Cl in dichloromethane or acetonitrile. (PPh4)(2)Se3Cl8. CH2Cl2 was also formed from GeSe, PPh4Cl and chlorine in acetonitrile. The Se-77-NMR spectra of the solutions show the presence of dynamical equilibria which, depending on composition, mainly contain SeCl2, SeCl4, Se2Cl2, SeCl62-, Se2Cl62-, and/or Se2Cl102- Solutions of AsCl3 and (PPh4)(2)Se-4 in acetonitrile upon chlorination with Cl-2 or PPh4AsCl6 yielded (PPh4)(2)Se2Cl6, while (PPh4)(2)As2Se4Cl12 was the product after chlorination with SOCl2. According to the X-ray crystal structure analyses the ions SeCl62-, Se2Cl9-, and Se2Cl102- have the known structures with octahedral coordination of the Se atoms. The structure of the Se3Cl82- ion corresponds to that of Se3Br82- consisting of three SeCl2 molecules associated via two Cl- ions. (PPh4)(2)Se4Cl12. CH2Cl2 is isotypic with the corresponding bromoselenate and contains anions in which three SeCl2 molecules are attached to a SeCl62- ion; there is a peculiar Se-Se interaction. [References: 22]