Synthesis and structure of cadmium complexes [Ph3EtP] 2 + [Cd2I6]2− · Me2C=O, [Ph3(iso-Pr)P] 2 + [CdI4]2−, [Ph3(isoBu)P] 2n + [Cd2I6] n 2− , and [Ph4P] 2 + [Cd2I6]2−

Abstract

Complexes with cadmium-containing anions [Ph3EtP]2+[Cd2I6]2− (I), [Ph3(iso-Pr)P]2+[CdI4]2− (II), [Ph3(iso-Bu)P]2n+[Cd2I6]n2− (III), and [Ph4P]2+[Cd2I6]2− (IV) were synthesized by the reaction of triphenylalkylphosphonium halides with cadmium iodide. The phosphorus atoms in the cations have a distorted tetrahedral coordination, as well as the cadmium atom in the mononuclear [CdI4]2− anion of complex II. The binuclear [Cd2I6]2− anions contain two terminal (t) CdI2 fragments linked to each other through two bridging (b) iodine atoms (Cd-Ib, 2.8626 and 2.8934 A in I, and 2.8652 and 2.8780 A in IV). The bond lengths Cd-It in I and IV are comparable (2.7245 and 2.7214 A in I and 2.7130 and 2.7252 A in IV). The anions of compound III are polymeric; the structural fragments [Cd2I6]2 (Cd-Ib, 2.8384 A; Cd-It, 2.6739 A) are associated by means of iodine atoms (I(1)…Cd(2A) 2.7973 A).