Outer-sphere-CT-Wechselwirkungen in organisch-anorganischen Ionenpaaren, IIa. Isolierung metastabiler Precursorkomplexe und thermischer OSCT-Elektronentransfer zwischen einem organischen π-Radikaldikation und Hexahalogeno-selenat(IV)-Komplexen: Erstmalige Erzeugung von SeCl6 ⨪

Abstract

Deeply coloured 1:1 electrolytes of the type Tris(dimethylamino)cyclopropendiylium )2+SeX6 2- (X = Cl, Br) have been obtained as metastable products of a kinetically controlled redox reaction and are compared with their Tellurium counterparts. According to UV and polarographic evidence there is strong OSCT -interaction between the SOMO of the organic moiety as acceptor and the alg*-HOMO of the ns2 anion as donor. The alg* donor capacity of ns2 anions of type EIX6 2- increases with decreasing atomic weight both of the central atom El and the ligand X. This trend and be rationalized on the basis o f a simple qualitative MO argument. Upon gentle heating the SeX6 2- systems are oxidized by their own counter cation. The novel SeX6⨪-species thus generated either disproportionates (X = Br) or acts as a selective radical halogenating agent (X = Cl) for the organic cation.