A rare case of a 2:2:1 ternary cocrystal of pyridine sulfides and trithiocyanuric acid

Abstract

We report a rare case of a 2:2:1 ternary cocrystal consisting of two trithiocyanuric acid molecules, two bis(pyridin-4-yl) sulfide molecules and 1,4-bis(pyridin-4-yl)tetrasulfane, namely, 1,3,5-triazinane-2,4,6-trithione–4-(pyridin-4-ylsulfanyl)pyridine–1,4-bis(pyridin-4-yl)tetrasulfane (2/2/1), 2C3H3N3S3·2C10H8N2S·C10H8N2S4. This interesting crystal structure with five neutral molecules per asymmetric unit was synthesized and characterized by means of X-ray diffraction (XRD) experiments and quantum-chemical modelling. Among various specific interactions, hydrogen and halogen bridges have a significant role in stabilizing the crystal structure. In particular, the role played by stacking interactions has been revealed by structure analysis and theoretical calculations. Crystallization was spontaneous and reproducible. One of the components, 1,4-bis(pyridin-4-yl)tetrasulfane, has been characterized by XRD for the first time.