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The design of a pharmaceutical cocrystal is based on the identification of specific hydrogen-bond donor and acceptor groups in active pharmaceutical ingredients (APIs) in order to choose a `complementary interacting' molecule that can act as an efficient coformer. 5-Fluorouracil (5FU) is a pyrimidine derivative with two N-H donors and C=O acceptors and shows a diversity of hydrogen-bonding motifs. Two 1:1 cocrystals of 5-fluorouracil (5FU), namely 5-fluorouracil-4-methylbenzoic acid (5FU-MBA), C4H3FN2O2·C8H8O2, (I), and 5-fluorouracil-3-nitrobenzoic acid (5FU-NBA), C4H3FN2O2·C7H5NO4, (II), have been prepared and characterized by single-crystal X-ray diffraction. In (I), the MBA molecules form carboxylic acid dimers [ R22(8) homosynthon]. Similarly, the 5FU molecules form two types of base pair via a pair of N-H...O hydrogen bonds [ R22(8) homosynthon]. In (II), 5FU interacts with the carboxylic acid group of NBA via N-H...O and O-H...O hydrogen bonds, generating an R22(8) ring motif (heterosynthon). Furthermore, the 5FU molecules form base pairs [ R22(8) homosynthon] via N-H...O hydrogen bonds. Both of the crystal structures are stabilized by C-H...F interactions. [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]

The asymmetric unit of the title compound, 2C5H3ClO2S·C10H8N2, is comprised of a molecule of 3-chlorothiophene-2-carboxylic acid (3TPC) and half of a molecule of 4,4′-bipyridine (BPY). A distinctive O--H′N-based synthon is present. Cl′Cl and π-π stacking interactions further stabilize the crystal structure, forming a two-dimensional network parallel to the bc plane. [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]

Background Design of new metal complexes is an interesting field for development of new functional molecular based materials. In this process by the usage of mixed functional ligands one can precisely tune the physical and chemical properties of those metal complexes. However, it is difficult to obtain the desired complex in many cases for factors like different coordination abilities of the ligands and the types of anions have a great influence on the structure. Results A series of five copper(II) complexes [Cu(Bipy) (5-TPC) 2(H2O)] (1), [Cu(Phen) (5-TPC) 2(H2O)] (2), [Cu(NO3) (4,7-Phen) (5-TPC) (H2O)].H2O (3), [Cu(Bipy) 2(5-TPC)]2.(ClO4)2 (4), and [Cu2(Bipy)4(H2PO4)] (5) (where Bipy = 2,2'-bipyridine, Phen = 1,10-phenanthroline, 4,7-Phen = 4,7-hydroxy-1,10-phenanthroline, 5-TPC = 5-chloro-2 thiophene carboxylate) has been synthesized and characterised using single crystal X-ray diffraction studies. In all the compounds, the N,N' ligand coordinates in a bidentate chelating manner and the copper has a square pyramidal geometry. Conclusions Complexes (1,2) are expected to be isostructural due to similarity of the N.N'-chelating ligands used, but due to the difference in supramolecular architectures no similar unit cells were observed. This is important in crystal engineering point of view. Complexes (1-4) possess the neutral mononuclear and complex (5) possesses a dinuclear entity. These entities are connected by intermolecular interactions like X...π, H...X, (X = Cl) generating supramolecular architectures. [ABSTRACT FROM AUTHOR]

The two centrosymmetric dinuclear copper paddle-wheel complexes tetrakis(μ-4-hydroxybenzoato-κ2 O: O′)bis[aquacopper(II)] dimethylformamide disolvate dihydrate, [Cu2(C7H5O3)4(H2O)2]·2C3H7NO·2H2O, (I), and tetrakis(μ-4-methoxybenzoato-κ2 O: O′)bis[(dimethylformamide-κ O)copper(II)], [Cu2(C8H7O3)4(C3H7NO)2], (II), crystallize with half of the dinuclear paddle-wheel cage unit in the asymmetric unit and, in addition, complex (I) has one dimethylformamide (DMF) and one water solvent molecule in the asymmetric unit. In both (I) and (II), two CuII ions are bridged by four syn, syn-η1:η1:μ carboxylate groups, showing a paddle-wheel cage-type structure with a square-pyramidal coordination geometry. The equatorial positions of (I) and (II) are occupied by the carboxylate groups of 4-hydroxy- and 4-methoxybenzoate ligands, and the axial positions are occupied by aqua and DMF ligands, respectively. The three-dimensional supramolecular metal-organic framework of (I) consists of three different R22(20) and an R44(36) ring motif formed via O-H...O and O W-H W...O hydrogen bonds. Complex (II) simply packs as molecular species. [ABSTRACT FROM AUTHOR]