J ‐Aggregate von 4‐Iod‐bis(dimethylamino)heptamethinium‐triiodid Synthese, Struktur und optische Eigenschaften

J-Aggregates of 4-Iodo-bis(dimethylamino)heptamethine Triiodide. — Synthesis, Structure, and Optical Properties Iodination of heptamethincyanine 2a gives the title compound 3. Its cations display all-trans configuration in solution and in the crystalline state. In contrast to cations of 2a, those of 3 form one-dimensional J aggregates, as proved by X-ray analysis and optical reflection spectroscopy.