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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]

A consistent set of data were obtained using a combination of electrochemical NMR and computational methods to support the fact that backfolded linkages result in dendrimers that are more encapsulating yet smaller than their extended counter parts. The conclusion was made by direct comparison of sets of dendimers that differed only in the relative structural element.

The rate coefficients for reactions of hydroxyl radical with aromatic hydrocarbons are measured in acetonitrile using a novel laser flash photolysis method. Comparison of kinetic data obtained in acetonitrile with those obtained in aqueous solution demonstrates an unexpected solvent effect on the reactivity of hydroxyl ion.

Quinones permeate our biotic environment, contributing to both homeostasis and cytotoxicity. All quinones generate reactive oxygen species through redox cycling, while partially substituted quinones also undergo arylation (Michael adduct formation) yielding covalent bonds with nucleophiles such as cysteinyl thiols. In contrast to reactive oxygen species, the role of arylation in quinone cytotoxicity is not well understood. We found that the arylating quinones, including unsubstituted 1,4-benzoquinone (1,4-BzQ) and partially substituted vitamin E congener γ-tocopherol quinone (γ-TQ), were cytotoxic, with γ-TQ > 1,4-BzQ, whereas the fully substituted nonarylating vitamin E congener α-tocopherol quinone was not. In vitro, both arylating quinones formed Michael adducts with the thiol nucleophile N-acetylcysteine (NAC) at rates where 1,4-BzQ > γ-TQ. In cultured cells, concurrent addition of NAC eliminated 1,4-BzQ caused toxicity, but preincubation was required for the same NAC detoxification effect on γ-TQ. These data clearly established the role of arylation in quinone toxicity and revealed that arylating quinone structure affects cytotoxicity by governing detoxification through the rate of adduct formation. Furthermore, arylating quinones induced endoplasmic reticulum (ER) stress by activating the pancreatic ER kinase (PERK) signaling pathway including elF2α, ATF4, and C/EBP homologous protein (CHOP). Detoxification by NAC greatly attenuates CHOP induction in arylating quinone-treated cells, suggesting that ER stress is a cellular mechanism for arylating quinone cytotoxicity. [ABSTRACT FROM AUTHOR]

Identification and quantitative estimation of quinone metabolites of gamma-tocopherol (gamma-T) and its derivative gamma-carboxyethyl hydroxychroman (gamma-CEHC) are complicated by their functions as arylating electrophiles. We hypothesize that their biological properties are expressed through arylating quinone electrophile addition (Michael reaction) with thiol nucleophiles in cells and tissues. Glutathione (GSH) reacted with gamma-tocopheryl quinone (gamma-TQ) to form the hydroquinone adduct, which was identified by electrospray time-of-flight MS (ESI-TOF-MS). Tetramethylammonium hydroxide (TMAH) thermochemolysis reduced and methylated quinones and cleaved and methylated thioether adducts. These relatively nonpolar derivatives were readily separated by GC and identified by MS fragmentation patterns. gamma-CEHC was synthesized and oxidized to a product identified as the quinone lactone (gamma-CEHC-QL). TMAH methylated both gamma-CEHC-QL and its GSH adduct without opening the lactone ring, and these products were separated by GC and identified by MS fragmentation patterns. gamma-CEHC-QL reacted with both the cysteinyl enzyme papain and fetal bovine serum, and TMAH thermochemolysis showed that each product mixture contained unreacted precursor and thioether adduct. Cytotoxicities of phenolic precursors, gamma-T and gamma-CEHC, and their quinones, gamma-TQ and gamma-CEHC-QL, respectively, were compared in COS1, NT2, 3T3, and N2a cell lines. Phenolic precursor gamma-T had a small effect only with NT2 and 3T3 cells while gamma-CEHC had no effect in any cell line. Arylating quinones were highly cytotoxic in all cell lines with gamma-TQ showing a significantly greater cytotoxicity than gamma-CEHC-QL. These data are consistent with our arylating electrophile hypothesis as an explanation for some biological activities of Ts through their quinone metabolites.