2,4-Diamino-6-methyl-1,3,5-triazin-1-ium hydrogen oxalate

Crystal structure and Hirshfeld surface analysis of 2,4-di-amino-6-methyl-1,3,5-triazin-1-ium tri-chloro-acetate monohydrate

In the crystal structure, the cations form hydrogen-bonded zigzag chains through centrosymmetric cyclic (8) N—H⋯N associations while the water mol­ecule acts as a double acceptor, linking the cations of the chain peripherally through amine N—H⋯O hydrogen bonds, closing cyclic (8) motifs, and as a double O—H⋯O donor, linking the anions, giving an overall three-dimensional structure.

The asymmetric unit of the title mol­ecular salt, C₄H₈N₅⁺·C₂Cl₃O₂⁻·H₂O, coomprises a 2,4-di­amino-6-methyl-1,3,5-triazin-1-ium cation, a tri­chloro­acetate anion and a water mol­ecule of solvation. The protonated N atom of the cation forms a hydrogen bond with a carboxyl O atom of the anion, which also acts as a hydrogen-atom acceptor with the water mol­ecule. The cations form centrosymmetric dimeric units through R₂²(8) N—H⋯N bond pairs and are extended into zigzag chains along the c-axis direction, also through similar cyclic R₂²(8) dual N—H⋯N hydrogen-bonding inter­actions. The water mol­ecule acts as a dual acceptor forming N—H⋯O hydrogen bonds between the amine groups of the cations, forming cyclic R₂³(8) motifs. The second H atom of the water mol­ecule also acts as a donor in an O—H⋯O hydrogen bond with the second carboxyl O atom, linking the chains along the b-axis direction. These interactions give rise to an overall three-dimensional supra­molecular structure. A Hirshfeld surface analysis was employed in order to study the inter­molecular inter­actions.

Supramolecular interactions in carboxylate and sulfonate salts of 2,6-diamino-4-chloropyrimidinium

Two new salts, namely 2,6-diamino-4-chloropyrimidinium 2-carboxy-3-nitrobenzoate, C₄H₆ClN₄⁺·C₈H₄NO₆^-, (I), and 2,6-diamino-4-chloropyrimidinium p-toluenesulfonate monohydrate, C₄H₆ClN₄⁺·C₇H₇O₃S^-·H₂O, (II), have been synthesized and characterized by single-crystal X-ray diffraction. In both crystal structures, the N atom in the 1-position of the pyrimidine ring is protonated. In salt (I), the protonated N atom and the amino group of the pyrimidinium cation interact with the carboxylate group of the anion through N-H...O hydrogen bonds to form a heterosynthon with an R₂²(8) ring motif. In hydrated salt (II), the presence of the water molecule prevents the formation of the familiar R₂²(8) ring motif. Instead, an expanded ring [i.e. R₃²(8)] is formed involving the sulfonate group, the pyrimidinium cation and the water molecule. Both salts form a supramolecular homosynthon [R₂²(8) ring motif] through N-H...N hydrogen bonds. The molecular structures are further stabilized by π-π stacking, and C=O...π, C-H...O and C-H...Cl interactions.

A novel potentiometric self-plasticizing polypyrrole sensor based on a bidentate bis-NHC ligand for determination of Hg(ii) cation

In this approach, a new potentiometric self-plasticizing polypyrrole sensor was constructed based on a bidentate bis-NHC ligand for the purpose of Hg²⁺cation determination.