Synthesis of a Hexachloro Sulfate(IV) Dianion Enabled by Polychloride Chemistry

Abstract

The preparation and structural characterization of [NEt3Me]2[SCl6] is described, which is the first example of a [SCl6]2− dianion and of a halosulfate anion of the type [SxXy]z− in general. This dianion belongs to the group of 14‐valence electron AB6E systems and forms an octahedral structure in the solid‐state. Interestingly, co‐crystallization with CH2Cl2 affords [NEt3Me]2[SCl6]⋅4 CH2Cl2 containing [SCl6]2− dianions with c4v symmetry. As suggested by quantum‐chemical calculations, the distortion of the structure is not caused by a stereochemically active lone pair but by enhanced hydrogen bonding interactions with CH2Cl2. At elevated temperatures, [NEt3Me]2[SCl6] decomposes to various sulfur chlorine compounds as shown by Raman spectroscopy. Cooling back to room temperature results in the selective formation of [NEt3Me]2[SCl6] which is comparable to the well‐studied SCl4.