2-Thio­cytosinium chloride

The title compound (systematic name: 4-amino-2-thioxo-2,3-dihydro­pyrimidin-1-ium chloride), C₄H₆N₃S⁺·Cl⁻, has two cations and two anions in the asymmetric unit. The two cations have nearly the same structure. Both are nearly planar, the largest distance from the non-H atoms to the least-squares plane through the six-membered ring atoms being 0.010 (2) Å. Both Cl⁻ ions serve as hydrogen-bond acceptors. One thiocytosinium cation forms N—H...Cl hydrogen bonds with three Cl⁻ anions and the other one with four Cl⁻ ions, giving a sheet parallel to (101). There is also an N—H...S inter­molecular hydrogen bond.

1-(1-Naphthyl­sulfon­yl)-1a,2,6,6a-tetra­hydro-1H,4H-1,3-dioxepino[5,6-b]azirine

The solid-state conformation of the title compound, C₁₅H₁₅NO₄S, has been established by X-ray crystallography. The orientation of the sulfonyl moiety is defined by the C—S—N—C torsion angle of −108.24 (16)°. The angle between the naphthyl ring and the direction of the S—N bond is 71.24 (18)°. The dioxepinoaziridine moiety system a boat–chair (BC) conformation. The crystal packing is defined by optimized π–π inter­actions between parallel naphthyl groups.

2-Thio­cytosinium bromide

The structure of the title compound (systematic name: 6-amino-2-thioxo-2,3-dihydro­pyrimidin-1-ium bromide), C₄H₆N₃S⁺·Br^-, has two 2-thio­cytosinium cations and two Br^- anions in the asymmetric unit and is isostructural with 2-thio­cytosinium chloride. Both six-membered rings are essentially planar. S atoms and Br^- anions serve as hydrogen-bond acceptors, forming sheets parallel to (101).