The title compound, C9H7NO2S crystallizes with two independent mol-ecules (A and B) in the asymmetric unit with Z = 8. Both mol-ecules are almost planar with a dihedral angle between the isoxazole and thio-phen rings of 3.67 (2)° in mol-ecule A and 10.00 (1) ° in mol-ecule B. The packing of mol-ecules A and B is of an ABAB⋯ type along the b-axis direction, the configuration about the C=C bond is Z. In the crystal, the presence of C-H⋯O, C-H⋯ N and π-π inter-actions [centroid-centroid distances of 3.701 (2) and 3.766 (2) Å] link the mol-ecules into a three-dimensional architecture. An analysis of Hirshfeld surfaces shows the importance of C-H⋯O and C-H⋯N hydrogen bonds in the packing mechanism of the crystalline structure.

In the title compound, C25H22N2O3S·0.04H2O, the central cyclo-hexane ring adopts a chair conformation. In the crystal, mol-ecules are linked by N-H⋯O, C-H⋯O, and C-H⋯N hydrogen bonds, forming the mol-ecular layers parallel to the bc plane, which inter-act by the van der Waals forces between them. A Hirshfeld surface analysis indicates that the contributions from the most prevalent inter-actions are H⋯H (41.2%), C⋯H/H⋯C (20.3%), O⋯H/H⋯O (17.8%) and N⋯H/H⋯N (10.6%).

The title compounds, 8-{1-[3-(cyclo-pent-1-en-1-yl)benz-yl]piperidin-4-yl}-2-meth-oxy-quinoline, C27H30N2O (I), and 8-{4-[3-(cyclo-pent-1-en-1-yl)benz-yl]piperazin-1-yl}-2-meth-oxy-quinoline, C26H29N3O (II), differ only in the nature of the central six-membered ring: piperidine in I and piperazine in II. They are isoelectronic (CH cf. N) and isotypic; they both crystallize in the triclinic space group P with very similar unit-cell parameters. Both mol-ecules have a curved shape and very similar conformations. In the biaryl group, the phenyl ring is inclined to the cyclo-pentene mean plane (r.m.s. deviations = 0.089 Å for I and 0.082 Å for II) by 15.83 (9) and 13.82 (6)° in I and II, respectively, and by 67.68 (6) and 69.47 (10)°, respectively, to the mean plane of the quinoline moiety (r.m.s. deviations = 0.034 Å for I and 0.038 Å for II). The piperazine ring in I and the piperidine ring in II have chair conformations. In the crystals of both compounds, mol-ecules are linked by C-H⋯π inter-actions, forming chains in I and ribbons in II, both propagating along the b-axis direction. The principal contributions to the overall Hirshfeld surfaces involve H⋯H contacts at 67.5 and 65.9% for I and II, respectively. The major contribution to the inter-molecular inter-actions in the crystals is from dispersion forces (E dis), reflecting the absence of classical hydrogen bonds.

The title compound, C24H24N2O5S, crystallizes with two independent mol-ecules (A and B) in the asymmetric unit. In the central ring systems of both mol-ecules, the tetra-hydro-furan rings adopt envelope conformations, the pyrrolidine rings adopt a twisted-envelope conformation and the six-membered ring is in a boat conformation. In mol-ecules A and B, the nine-membered groups attached to the central ring system are essentially planar (r.m.s. deviations of 0.002 and 0.003 Å, respectively). They form dihedral angles of 64.97 (9) and 56.06 (10)°, respectively, with the phenyl rings. In the crystal, strong inter-molecular O-H⋯O hydrogen bonds and weak inter-molecular C-H⋯O contacts link the mol-ecules, forming a three-dimensional network. In addition weak π-π stacking inter-actions [centroid-to centroid distance = 3.7124 (13) Å] between the pyrrolidine rings of the nine-membered groups of A mol-ecules are observed. Hirshfeld surface analysis and two-dimensional fingerprint plots were used to qu-antify the inter-molecular inter-actions present in the crystal, indicating that the environments of the two mol-ecules are very similar. The most important contributions for the crystal packing are from H⋯H (55.8% for mol-ecule A and 53.5% for mol-ecule B), O⋯H/H⋯O (24.5% for mol-ecule A and 26.3% for mol-ecule B) and C⋯H/H⋯C (12.6% for mol-ecule A and 15.7% for mol-ecule B) inter-actions.

In the title compound, C15H15Br2NO2, two bridged tetra-hydro-furan rings adopt envelope conformations with the O atom as the flap. The pyrrolidine ring also adopts an envelope conformation with the spiro C atom as the flap. In the crystal, the mol-ecules are linked into dimers by pairs of C-H⋯O hydrogen bonds, thus generating R 2 2(18) rings. The crystal packing is dominated by H⋯H, Br⋯H, H⋯π and Br⋯π inter-actions. One of the Br atoms is disordered over two sites with occupation ratio of 0.833 (8):0.167 (8).

In the mol-ecular structure of the title compound, C20H21N3O7, the quinoline ring system is slightly bent, with a dihedral angle between the phenyl and the pyridine rings of 3.47 (7)°. In the crystal, corrugated layers of mol-ecules extending along the ab plane are generated by C-H⋯O hydrogen bonds. The inter-molecular inter-actions were qu-anti-fied by Hirshfeld surface analysis and two-dimensional fingerprint plots. The most significant contributions to the crystal packing are from H⋯H (42.3%), H⋯O/O⋯H (34.5%) and H⋯C/ C⋯H (17.6%) contacts. Mol-ecular orbital calculations providing electron-density plots of the HOMO and LUMO as well as mol-ecular electrostatic potentials (MEP) were computed, both with the DFT/B3LYP/6-311 G++(d,p) basis set. A mol-ecular docking study between the title mol-ecule and the COVID-19 main protease (PDB ID: 6LU7) was performed, showing that it is a good agent because of its affinity and ability to adhere to the active sites of the protein.

Co-crystallization from methanol of 3-amino-1H-pyrazole with 3,5-di-nitro-benzoic acid produces 3-amino-1H-pyrazol-2-ium 3,5-di-nitro-benzoate monohydrate, C3H6N3 +·C7H3N2O6 -·H2O, (I), while similar co-crystallization of this pyrazole with an equimolar qu-antity of fumaric acid produces bis-(3-amino-1H-pyrazol-2-ium) fumarate-fumaric acid (1/1), 2C3H6N3 +·C4H2O4 2-·C4H4O4, (II). The reaction of 3-amino-1H-pyrazole with a dilute solution of nitric acid in methanol yields a second, ortho-rhom-bic polymorph of 3-amino-1H-pyrazol-2-ium nitrate, C3H6N3 +·NO3 -, (III). In each of (I)-(III), the bond distances in the cation provide evidence for extensive delocalization of the positive charge. In each of (I) and (II), an extensive series of O-H⋯O and N-H⋯O hydrogen bonds links the components into complex sheets, while in the structure of (III), the ions are linked by multiple N-H⋯O hydrogen bonds into a three-dimensional arrangement. Comparisons are made with the structures of some related compounds.

The synthesis, isolation and crystal structures of nickel(II) carbonyl, aceto-nitrile and ammonia complexes supported by a dianionic, pyridine dipyrrolide pincer ligand [pyrr2py]2-, namely, carbonyl[2,2'-(pyridine-2,6-di-yl)bis-(3,5-di-p-tolyl-pyrrolido-κN)]-nickel(II), [Ni(C41H33N3)(CO)], ammine[2,2'-(pyridine-2,6-di-yl)bis-(3,5-di-p-tolyl-pyrrolido-κN)]nickel(II), [Ni(C41H33N3)(NH3)], and (aceto-nitrile-κN)[2,2'-(pyridine-2,6-di-yl)bis-(3,5-di-p-tolyl-pyrrolido-κN)]nickel(II), [Ni(C41H33N3)(CH3CN)], as well as the free ligand 2,6-bis-(3,5-di-p-tolyl-pyrrol-2-yl)pyridine, C41H35N3 or [pyrr2py]H2 are reported. The nickel complexes are four-coordinate and adopt a square-planar geometry. The CO stretch of the nickel-bound carbon monoxide ligand of [pyrr2py]Ni(CO) has been observed at 2101 cm-1. The ammonia and aceto-nitrile complexes, [pyrr2py]Ni(NH3) and [pyrr2py]Ni(NCMe) feature all-nitro-gen coordination spheres around nickel consisting of different N-donor ligand types.

The structure of the racemic version of the natural product Goniotamirenone C [racemic anti-6-(2-chloro-1-hy-droxy-2-phenyl-eth-yl)-2H-pyran-2-one, C13H11ClO3] at 150 K is reported. The compound crystallizes with monoclinic (P21/n) symmetry and with Z' = 2. One independent mol-ecule is ordered while the other independent mol-ecule exhibits an inter-esting whole-mol-ecule enanti-omeric disorder with occupancies of 0.846 (4) and 0.154 (4). The independent mol-ecules are hydrogen bonded with -OH⋯O=C linkages into chains that run parallel to the a axis. This structural analysis corrects our previous assignment as the syn isomer [Meesakul et al. (2020 ▸). Phytochemistry, 171, 112248-112255].

In the title bicyclic trinuclear pyrazolate amino-alcohol complex, [Cu3(C5H7N2)2(C6H14NO3)2]Br2·1.5H2O, the central Cu atom lies on a center of symmetry and is involved in the formation of two five-membered rings. It has a coordination number of 4, is in a distorted tetra-hedral environment and is connected by the bridging oxygen atoms of the deprotonated OH groups of different amino-alcohol groups, and by the N atoms of deprotonated di-methyl-pyrazole ligands. The peripheral Cu atom is in a trigonal-bipyramidal coordination environment formed by the nitro-gen atom of the deprotonated bridging di-methyl-pyrazole unit, the bridging oxygen atom of the deprotonated OH group, two oxygen atoms of the protonated hy-droxy groups and the nitro-gen atom of tri-ethano-lamine. One of the C atoms and the Br- anion were found to be disordered over two positions with occupancy factors of 0.808 (9):0.192 (9) and 0.922 (3):0.078 (3), respectively.