N‑(6-Methyl-2-pyridyl)mesitylenesulfonamide: An Efficient Template for Polyiodides

A series of (poly-)­iodides featuring I–, I3–, I5–, and I7– anions and even the challenging I42– dianion have been synthesized and structurally characterized by X-ray diffraction. The V-shaped sulfapyridine derivative N-(6-methyl-2-pyridyl)­mesitylenesulfonamide acts as the countercation in all compounds. Depending on stoichiometry and solvent, the different products are reproducibly accessible as phase-pure solids. N–H···I hydrogen bonds connect cations and iodide or triiodide anions to salts with related packing features. The same interactions allow for the stabilization of the much less popular tetraiodide, subtending this linear species between two cations. Monocationic pairs of (formally hemiprotonated) sulfonamides pack according to a common pattern and exert a pronounced templating effect on the formation of penta- and heptaiodides; their influence is based on charge, size, and shape matching. The higher polyiodides can readily be discerned by their Raman spectra.