Cytosinium orotate dihydrate

The title compound, C₄H₆N₃O⁺·C₅H₃N₂O₄⁻·2H₂O or Cyt⁺·Or⁻·2H₂O, was synthesized by a reaction between cytosine (4-amino-2-hy­droxy­pyrimidine, Cyt) and orotic acid (2,4-dihy­droxy-6-carb­oxy­pyrimidine, Or) in aqueous solution. The two ions are joined by two N⁺—H...O⁻ (±)-(CAHB) hydrogen bonds, forming a dimer with graph-set motif R₂²(8). In the crystal, the ion pairs of the asymmetric unit are joined by four N—H...O inter­actions to adjacent dimers, forming hydrogen-bonded rings with R₂²(8) graph-set motif in a two-dimensional network. The formation of the three-dimensional array is facilitated by water mol­ecules, which act as bridges between structural sub-units linked in R₃²(8) and R₃²(7) hydrogen-bonded rings. The orotate anion is essentially planar, as the dihedral angle between the planes defined by the carboxylate group and the uracil fragment is 4.0 (4)°.

4-Meth­oxy­benzamidinium bromide

The title salt, C₈H₁₁N₂O⁺·Br⁻, was synthesized by the reaction between 4-meth­oxy­benzamidine (4-amidino­anisole) and hydro­bromic acid. In the cation, the amidinium group has two similar C—N bonds [1.304 (2) and 1.316 (2) Å], and its plane forms a dihedral angle of 31.08 (5)° with the benzene ring. The ions are associated in the crystal into a three-dimension hydrogen-bonded supra­molecular network featuring N—H⁺...Br⁻ inter­actions.

Benzamidinium 2-meth­oxy­benzoate

The title mol­ecular salt, C₇H₉N₂^+.C₈H₇O₃⁻, was synthesized by reaction between benzamidine (benzene­carboximidamide) and 2-meth­oxy­benzoic acid. In the cation, the amidinium group has two similar C—N bonds [1.3070 (17) and 1.3145 (16) Å] and is almost coplanar with the benzene ring, making a dihedral angle of 5.34 (12)°. In the anion, the meth­oxy substituent forces the carboxyl­ate group to be twisted by 69.45 (6)° with respect to the plane of the aromatic fragment. In the crystal, the components are connected by two N⁺—H...O⁻ (±)CAHB (charge-assisted hydrogen bonds), forming centrosymmetric ionic dimers with graph-set motif R₂²(8). These ionic dimers are then joined in ribbons running along the b-axis direction by another R₄²(8) motif involving the remaining N⁺—H...O⁻ hydrogen bonds. Remarkably, at variance with the well known carb­oxy­lic dimer R₂²(8) motif, the carboxyl­ate–amidinium pair is not planar, the dihedral angle between the planes defined by the CN₂⁺ and CO₂⁻ atoms being 18.57 (12)°.