The reaction of thiourea and 1,3-dimethylthiourea towards organoiodines: oxidative bond formation and halogen bonding

Halogen, chalcogen, and hydrogen bonding in organoiodine cocrystals of heterocyclic thiones: imidazolidine-2-thione, 2-mercaptobenzimidazole, 2-mercapto-5-methylbenzimidazole, 2-mercaptobenzoxazole, and 2-mercaptobenzothiazole

Through the combination of heterocyclic thiones with variation in the identity of the heterocyclic elements, namely, imidazolidine-2-thione, 2-mercaptobenzimidazole, 2-mercapto-5-methylbenzimidazole, 2-mercaptobenzoxazole, and 2-mercaptobenzothiazole with the common halogen-bond donors 1,2-, 1,3-, and 1,4-diiodotetrafluorobenzene, 1,3,5-trifluorotriiodobenzene, and tetraiodoethylene, a series of 18 new crystalline structures were characterized. In most cases, N-H...S hydrogen bonding was observed, with these interactions in imidazole-containing structures typically resulting in two-dimensional motifs (i.e. ribbons). Lacking the second N-H group, the thiazole and oxazole hydrogen bonding resulted in only dimeric pairs. C-I...S and C-I...I halogen bonding, as well as C=S...I chalcogen bonding, served to consolidate the packing by linking the hydrogen-bonding ribbons or dimeric pairs.

The Halogen Bonding Proclivity of the sp3 Sulfur Atom as a Halogen Bond Acceptor in Cocrystals of Tetrahydro-4H-thiopyran-4-one and Its Derivatives

In this work, we present a systematic study of the capability of the sp³ hybridized sulfur atom for halogen bonding both in a small building block, tetrahydro-4H-thiopyran-4-one, and two larger ones derived from it, Schiff bases with a morpholine fragment on the other end of the molecule. These three building blocks were cocrystallized with six perhalogenated aromates: 1,4-diiodotetrafluorobenzene, 1,3,5-triiodotrifluorobenzene, 1,3-diiodotetrafluorobenzene, 1,2-diiodotetrafluorobenzene, iodopentafluorobenzene, and 1,4-dibromotetrafluorobenzene. Out of the 18 combinations, only 7 (39%) yielded cocrystals, although with a high occurrence of the targeted I···S halogen bonding motif in all cocrystals (71%), and in imine cocrystals the I···O_morpholine motif (100%) as well as, surprisingly, the I···N_imine motif (100%). The I···S halogen bonds presented in this work feature lower relative shortening values than those for other types of sulfur atoms; however, the sp³ sulfur atom could potentially be more specific an acceptor for halogen bonding.

Isolation of unique heterocycles formed from pyridine-thiocarboxamides as diiodine, iodide, or polyiodide salts

The reaction of pyridine-thiocarboxamides with I2 provided a variety of novel heterocyclic products as iodide, triiodide, and/or pentaiodide salts. Bismuth triiodide was incorporated as a crystallization aid to access other structural types.