Crystal structure of 2,6-bis(3-hydroxy-3-methylbut-1-yn-1-yl)pyridine monohydrate

In the title pyridine derivative, C15H17NO2·H2O, the two OH groups are oriented in directions opposite to each other with respect to the plane of the pyridine ring. In the crystal, hydrogen bonds between the pyridine molecule and the water molecule, viz. Ohydroxy—H...Owater, Ohydroxy—H...Ohydroxy, Owater—H...Ohydroxy and Owater—H···Npyridine, result in the formation of a ribbon-like structure running along [011].

SOLVATION CONTRIBUTIONS OF PYRIDINE FUNCTIONAL GROUPS IN TRANSFER ENTHALPY OF AMINE FROM METHANOL TO ACETONITRILE, DIMETHYL SULFOXIDE AND DIMETHYLFORMAMIDE

Quantum-chemical calculations of the energy and structure of pyridine molecule (Py) in the free state, methanol (MeOH), acetonitrile (AN), dimethyl sulfoxide (DMSO) and dimethylformamide (DMF) have been performed using the density functional theory (DFT) at the B3LYP with the 6-31G basic set supplemented by polarization and diffuse functions and within the model of the self-consistent reactive field (PCM). It was found that the transfer of the pyridine molecule from the free state to the MeOH, AN, DMF and DMSO media leads to: an increase in bond distances only between nitrogen and carbon atoms of amine; significant changes in the charges on the carbon atoms associated with the reaction center (the growth of positive charges varies in the series: DMF = DMSO < MeOH = AN); an increase in the positive charge on hydrogen atoms, which varies in the series: MeOH = AN < DMF = DMSO. A comparative analysis of the results from quantum chemical calculations was carried out with data on transfer enthalpies of amine from MeOH to AN, DMF and DMSO (ΔtrH°(Py)MeOH → solv) which were obtained by calorimetric method. It was found that the resolvation of the nitrogen atom gives the major contribution to the change in the solvate state of pyridine when the composition of the solvent MeOH → DMF and MeOH → AN changes. In case of transfer of Py from MeOH to DMSO, contributions from the resolvation of the nitrogen atom and the hydrocarbon radical to the overall energy of the resolvation of molecule are approximately the same.Forcitation:Kuz’mina I.A., Volkova M.A., Kuz’mina K.I., Belova N.V., Sharnin V.A. Solvation contributions of pyridine functional groups in transfer enthalpy of amine from methanol to acetonitrile, dimethyl sulfoxide and dimethylformamide. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 3. P. 4-9

Crystal structure of 2-(azaniumylmethyl)pyridinium bis(hydrogen squarate)

The asymmetric unit of the title compound, C6H10N22+·2C4HO4−, comprises two hydrogen squarate (Hsq−; systematic name: 2-hydroxy-3,4-dioxocyclobutanolate) anions and a 2-(azaniumylmethyl)pyridinium dication. The squaric acid molecules each donate an H atom to the N atoms of the pyridine ring and the aminomethyl units of a 2-(aminomethyl)pyridine molecule, forming the 1:2 salt. The Hsq−anions are linked by strong O—H...O hydrogen bonds and an N—H...O hydrogen bond links the 2-(azaniumylmethyl)pyridinium cation to one of the squaric acid anions. The crystal structure features additional N—H...O and O—H...O hydrogen bonds, π–π stacking and unusual weak C—O...π(ring) interactions.

2-Carboxylatopyridinium–4-nitrophenol (1/1)

In the title 1:1 adduct, C6H5NO3·C6H5NO2, both molecules are almost planar (r.m.s. deviations for the non-H atoms = 0.027 and 0.023 Å for 4-nitrophenol and 2-carboxylatopyridinium, respectively). The pyridine molecule crystallizes as a zwitterion (nominal proton transfer from the carboxylic acid group to the N atom in the ring). In the crystal, inversion dimers of the zwitterions linked by pairs of N—H...O hydrogen bonds generateR22(10) loops; two 4-nitrophenol molecules link to the dimer by O—H...O hydrogen bonds, generating a four-molecule aggregate. These are linked by C—H...O interactions, forming a three-dimensional network.

Aquachloridotriphenyltin(IV)–2-[1-(4-pyridylmethyl)-1H-imidazol-2-yl]pyridine (1/1)

In the title compound, [Sn(C6H5)3Cl(H2O)]·C14H12N4, Ph3SnCl(H2O) and 2-[1-(4-pyridylmethyl)-1H-imidazol-2-yl]pyridine molecules cocrystallize in the same structure. Each Sn atom displays a distorted trigonal–bipyramidal geometry composed of three phenyl groups, one Cl− ion and one coordinated water molecule, which links, via hydrogen bonding, the Ph3SnCl(H2O) molecule to the cocrystallized 2-[1-(4-pyridylmethyl)-1H-imidazol-2-yl]pyridine molecule to generate an infinite chain structure.

Monoclinic polymorph of the 1:1 adduct of sulfathiazole with pyridine

The asymmetric unit of the title compound, C9H9N3O2S2·C5H5N, contains a sulfathiazole and a pyridine molecule linked via N—H...N hydrogen bonds, as in the tetragonal polymorph. The monoclinic polymorph is unstable in air at ambient conditions and loses pyridine giving sulfathiazole. The monoclinic polymorph belongs to the class of disappearing polymorphs; it was the first polymorph to be obtained, but could not be obtained again, after the tetragonal polymorph was crystallized.