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The crystals of two new salts, 2,6-diamino-4-chloropyrimidin-1-ium 5-chlorosalicylate, C4H6ClN4 +.C7H4ClO3 -, (I), and bis(2,6-diamino-4-chloropyrimidin-1- ium) naphthalene-1,5-di-sulfonate, 2C4H6ClN4 +.C10H6O6S2 2-, (II), have been synthesized and characterized by single-crystal X-ray diffraction. In both compounds, the N atom of the pyrimidine group in between the amino substituents is protonated and the pyrimidinium cation forms a pair of N-- H. . .O hydrogen bonds with the carboxylate/sulfonate ion, leading to a robust R2 2(8) motif (supramolecular heterosynthon). In compound (I), a selfcomplementary base pairing involving the other pyrimidinium ring nitrogen atom and one of the amino groups via a pair of N--H. . .N hydrogen bonds [R2 ²(8) homosynthon] is also present. In compound (II), the crystallographic inversion centre coincides with the inversion centre of the naphthalene-1,5- disulfonate ion and all the sulfonate O atoms are hydrogen-bond acceptors, generating fused-ring motifs and a quadruple DDAA array. A halogen-bond (Cl. . .Cl) interaction is present in (I) with a distance and angle of 3.3505 (12) Å and 151.37 (10)°, respectively. In addition, a C--Cl. . .π interaction and a π-π interaction in (I) and a π-π interaction in (II) further stabilize these crystal structures. [ABSTRACT FROM AUTHOR]

The asymmetric unit of the title co-crystal, C12H9N5O·C7H6O3, contains one molecule of N6-benzoyladenine (BA) and one molecule of 4-hydroxybenzoic acid (HBA). The N6-benzoyladenine (BA) has an N(7)--H tautomeric form with nonprotonated N-1 and N-3 atoms. This tautomeric form is stabilized by a typical intramolecular N--H⋯O hydrogen bond between the carbonyl (C＝O) group and the N(7)--H hydrogen on the Hoogsteen face of the purine ring, forming a graph-set S(7) ring motif. The primary robust R²2(8) ring motif is formed in the Watson-Crick face via N--H⋯O and O--H⋯N hydrogen bonds (involving N1, N6--H and the carboxyl group of HBA).Weak interactions, such as, C--H⋯π and π-π are also observed in this crystal structure. [ABSTRACT FROM AUTHOR]

In the crystal structure of the title compound, 5-fluorocytosinium picrate, C4H5FN3O+·C6H2N3O7-, one N heteroatom of the 5-fluorocytosine (5FC) ring is protonated. The 5FC ring forms a dihedral angle of 19.97 (11)° with the ring of the picrate (PA-) anion. In the crystal, the 5FC+ cation interacts with the PA- anion through three-centre N--H⋯O hydrogen bonds, forming two conjoined rings having R2¹(6) and R1²(6) motifs, and is extended by N--H⋯O hydrogen bonds and C--H⋯O interactions into a two-dimensional sheet structure lying parallel to (001). Also present in the crystal structure are weak C--F⋯π interactions. [ABSTRACT FROM AUTHOR]

In the title salt, C6H9ClN3+·C6H3O4S-, the cations and anions are linked via O-H⋯O and N-H⋯O hydrogen bonds, forming R66(37) ring motifs that are inter?connected with each other, producing sheets. Separate parallel inversion-related sheets are linked through N-H⋯N and [pi]-[pi] stacking inter?actions [centroid-centroid distance = 3.5414 (13) Å], forming double layers parallel to (101). Weak C-H⋯O and C-H⋯S hydrogen bonds, as well as C-H⋯π inter?actions, connect the double layers into a three-dimensional network. [ABSTRACT FROM AUTHOR]

The asymmetric unit of the title co-crystal, C12H9N5O0.5C6H10O4, consists of one molecule of N6-benzoyladenine (BA) and one half-molecule of adipic acid (AA), the other half being generated by inversion symmetry. The dihedral angle between the adenine and phenyl ring planes is 26.71 (7)°. The N6-benzoyladenine molecule crystallizes in the N(7)--H tautomeric form with three non-pro tonated N atoms. This tautomeric form is stabilized by intramolecular N--H⋯O hydrogen bonding between the carbonyl (CO) group and the N(7)--H hydrogen atom on the Hoogsteen face of the purine ring, forming an S(7) ring motif. The two carboxyl groups of adipic acid interact with the Watson-Crick face of the BA molecules through O--H⋯N and N--H⋯O hydrogen bonds, generating an R2²(8) ring motif. The latter units are linked by N--H⋯N hydrogen bonds, forming layers parallel to (105. A weak C--H⋯O hydrogen bond is also present, linking adipic acid molecules in neighbouring layers, enclosing R²2(10) ring motifs and forming a three-dimensional structure. C=O⋯π and C--H⋯π interactions are also present in the structure. [ABSTRACT FROM AUTHOR]

The asymmetric unit of the title compound, 4C4H4FN3O•C3H6N6, comprises of two independent 5-fluoro-cytosine (5FC) molecules (A and B) and one half-molecule of melamine (M). The other half of the melamine molecule is generated by a twofold axis. 5FC molecules A and B are linked through two different homosynthons [R2² (8) ring motif]; one is formed via a pair of N--H⋯O hydrogen bonds and the second via a pair of N--H⋯N hydrogen bonds. In addition to this pairing, the O atoms of 5FC molecules A and B inter-act with the N2 amino group on both sides of the melamine molecule, forming a DDAA array of quadruple hydrogen bonds and generating a supramolecular pattern. The 5FC (molecules A and B) and two melamine molecules interact via N--H⋯O, N--H⋯N and N--H⋯O, N--H⋯N, C--H⋯F hydrogen bonds forming R66(24) and R44(15) ring motifs. The crystal structure is further strengthened by C--H⋯F, C--F⋯π and π--π stacking interactions. [ABSTRACT FROM AUTHOR]

In the title molecular salt, C12H10N5O+·NO3-, the adenine unit has an N9-protonated N(7)--H tautomeric form with non-protonated N¹ and N³ atoms. The dihedral angle between the adenine ring system and the phenyl ring is 51.10(10)°. The typical intra­molecular N7--H···O hydrogen bond with an S(7) graph-set motif is also present. The benzoyl­adeninium cations also form base pairs through N--H···O and C--H···N hydrogen bonds involving the Watson-Crick face of the adenine ring and the C and O atoms of the benzoyl ring of an adjacent cation, forming a supra­molecular ribbon with R2²(9) rings. Benzoyl­adeninum cations are also bridged by one of the oxygen atoms of the nitrate anion, which acts as a double acceptor, forming a pair of N--HH···O hydrogen bonds to generate a second ribbon motif. These ribbons together with p-p stacking inter­actions between the phenyl ring and the five- and six-membered adenine rings of adjacent mol­ecules generate a three-dimensional supra­molecular architecture. [ABSTRACT FROM AUTHOR]