Ionic cocrystals of dithiobispyridines: the role of I…I halogen bonds in the building of iodine frameworks and the stabilization of crystal structures. Issue 8 (7th July 2021)

• Record Type: Journal Article
• Authors: Wzgarda-Raj, Kinga; Nawrot, Martyna; Rybarczyk-Pirek, Agnieszka J.; Palusiak, Marcin
• Is Part Of: Acta crystallographica. Volume 77:Issue 8(2021)
• Page Start: 458
• Page End: 466
• Publication Date: 2021-07-07
• Subjects: pyridine -- cocrystal -- salt -- hydrogen bonding -- halogen bonding -- supramolecular chemistry -- quantum chemistry -- proton transfer -- crystal structure -- proton sponge; Crystallography -- Periodicals; Crystals -- Periodicals; 548.3
• DOI: 10.1107/S2053229621006306
• Languages: English
• ISSNs: 2053-2296

Abstract

Abstract : 2‐Mercapto‐ and 4‐mercaptopyridine in iodine solution condense into dithiopyridines. In the crystalline state, these compounds exist as protonated molecules embedded in a network of iodine molecules and iodide anions. All the molecular components are stabilized by various intermolecular interactions, viz. hydrogen, halogen and chalcogen bonds. Abstract : It has been confirmed that mercaptopyridines undergo spontaneous condensation in redox reaction with iodine‐forming dithiopyridines. In the solid state, these compounds are protonated at the N atoms and cocrystallize with iodine forming salt structures, namely, 2‐[(pyridin‐2‐yl)disulfanyl]pyridinium triiodide sesquiiodine, C10 H9 N2 S2 + ·I3 − ·1.5I2, and 4, 4′‐(disulfanediyl)dipyridinium pentaiodide triiodide, C10 H10 N2 S2 2+ ·I5 − ·I3 − . Dithiopyridine cations are packed among three‐dimensional frameworks built from iodide anions and neutral iodine molecules, and are linked by hydrogen, halogen and chalcogen interactions. Quantum chemical computations indicated that dithiopyridines exhibit anomalously high nitrogen basicity which qualify them as potential proton sponges.