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Triiodide salts are of interest for a variety of applications, including but not limited to electrochemical and photochemical devices, as antimicrobials and disinfectants, in supramolecular chemistry and crystal engineering, and in ionic liquids and deep eutectic solvents. Our work has focused on the design of salt–solvate cocrystals and deep eutectic solvents in which the triiodide anion interacts as a halogen bond acceptor with organoiodine molecules. To understand structure–property relationships in these hybrid materials, it is essential to have benchmark structural and physical data for the parent triiodide salt component. Herein, we report the structure and thermal properties of eight new triiodide salts, three of which exhibit polymorphism: tetrapentylammonium triiodide (1a and 1b), tetrahexylammonium triiodide (2), trimethylphenylammonium triiodide (3), trimethylbenzylammonium triiodide (4), triethylbenzylammonium triiodide (5), tri-n-butylbenzylammonium triiodide (6), 3-methylbenzothizolium triiodide (7a and 7b), and 2-chloro-1-methylpyridinium triiodide (8a and 8b). The structural features of the triiodide anion, Raman spectroscopic analysis, and melting and thermal decomposition behavior of the salts, as well as a computational analysis of the polymorphs, are discussed. The polymorphic pairs here are distinguished by symmetric versus asymmetric triiodide anions, as well as different packing patterns. Computational analyses revealed more subtle differences in their isosurface plots. Importantly, this study provides reference data for these new triiodide salts for comparison to hybrid cocrystals and deep eutectic solvents formed from their combination with various organoiodines. [ABSTRACT FROM AUTHOR]

We recently reported the first examples of S−Cl⋅⋅⋅O halogen bonding complemented by short F⋅⋅⋅F contacts between neighboring chains that resulted in stabilized crystals of ClSO2(CF2)4SO2Cl and ClSO2(CF2)6SO2Cl. More recently, other researchers studied our crystallographic data further using an Independent Gradient Model (IGM), and they suggested if one goes beyond IUPAC's proposed 'less than the sum of the van der Waals radii' criterion that even more noncovalent interactions between fluorine atoms on neighboring chains as well as Cl⋅⋅⋅Cl, Cl⋅⋅⋅S, O⋅⋅⋅F, and O⋅⋅⋅S attractive interactions can be found. With that said, we have prepared samples of the related BrSO2(CF2)nSO2Br derivatives (where n=4, 6, 8, and others), which give rise to even stronger S−Br⋅⋅⋅O halogen bonding interactions complemented minimally by O⋅⋅⋅F and F⋅⋅⋅F intermolecular interactions as shown by X‐ray crystallography and computational chemistry using IGM isosurface plots. Additional spectroscopic characterization (multinuclear NMR, FT‐IR, and MS) of the disulfonyl bromide derivatives BrSO2(CF2)4SO2Br, BrSO2(CF2)6SO2Br, and BrSO2(CF2)8SO2Br has also been obtained as well as some preliminary spectroscopic evidence for BrSO2(CF2)2SO2Br and BrSO2CF2O(CF2)2OCF2SO2Br. The implication of these results toward the preparation of the corresponding disulfonyl iodides is discussed. [ABSTRACT FROM AUTHOR]