Acta Crystallographica Section C Structural Chemistry最新文献

A recent communication on Ru-catalyzed C-H bond arylation with 4-aminoantipyrine (AP) reported the synthesis of AP benzamides. In order to provide additional support to the published structures of AP benzamides, crystallization by high-throughput (HTP) encapsulated nanodroplet crystallization (ENaCt) was undertaken. This allowed for conclusive structure determination by single-crystal X-ray diffraction analysis (SCXRD). This article describes the crystallization and X-ray crystal structure of N-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-2-methylbenzamide, C₁₉H₁₉N₃O₂, as a benzamide bearing 4-aminoantipyrine, providing structural confirmation. X-ray structure analysis reveals intermolecular hydrogen-bonding interactions between the AP benzamide N-H proton and the carbonyl O atom of the AP moiety.

Binary chalcogen halogen EX₄ species represent intriguing systems in terms of chemical bonding theories, such as hypervalency and stereoactivity of lone electron pairs. Instead of a simple molecular EX₄ structure, selenium tetrachloride forms an ionic pair, Cl₃Se⁺Cl^-, that assembles into a tetrameric (SeCl₄)₄ structure, namely, tetra-μ₃-chlorido-dodecachloridotetraselenium. This article describes the charge-density analysis of the tetrameric molecule of β-SeCl₄ based on the aspherical model obtained from Hirshfeld Atom Refinement of the tetrameric molecule and of an explicit cluster of 15 tetramers that simulates the crystal packing. Deformation density, electron localization function (ELF) and Quantum Theory of Atoms in Molecules (QTAIM) were used to evaluate the bonding situation, the electron-density distribution around the Se atom and the interaction energy of the tetramer.

Starting from (p-tolylsulfinyl)ferrocene (1), a mixture of the complete series [CpFe{C₅H_5-n(SOTol-p)_n}] (n = 2-4) (2-4) in all regioisomers was obtained. After chromatographic separation, crystals of 1,2-bis[(4-methylbenzene)sulfinyl]ferrocene, 2a, and 1,3-bis[(4-methylbenzene)sulfinyl]ferrocene, 2b, both [Fe(C₅H₅)(C₁₉H₁₇O₂S₂)], as well as of 1,2,3-tris[(4-methylbenzene)sulfinyl]ferrocene, [Fe(C₅H₅)(C₂₆H₂₃O₃S₃)], 3a, and 1,2,3,4-tetrakis[(4-methylbenzene)sulfinyl]ferrocene ethyl acetate 0.75-solvate, [Fe(C₅H₅)(C₃₃H₂₉O₄S₄)]·0.75C₄H₈O₂, 4, could be isolated. Their molecular and crystal structures are compared with each other and also with the so far unreported structures of related 1,2-bis(phenylsulfanyl)ferrocene, [Fe(C₅H₅)(C₁₇H₁₃S₂)], 5, and 1,2,3,4-tetrakis(phenylsulfanyl)ferrocene, [Fe(C₅H₅)(C₂₉H₂₁S₄)], 6. In all the sulfinyl structures, the O atoms of the S=O groups are in equatorial positions, except for that in tetrasubstituted 4. All the arene rings of these compounds (except for one ring in 4) are in axial positions directed away from the Fe atom, mostly in a near perpendicular orientation with respect to the plane of the cyclopentadienyl ring. The main intermolecular interactions in the crystals are C-H...H-C, C-H...π and C-H...O, while C-H...S interactions are much less important, except for tetrasulfanyl compound 6. π-π interactions (intramolecular) are only important in compound 3a. Hirshfeld analysis shows that dispersion terms are dominant for the interaction energies of all six compounds. In general, the calculated total interaction energies increase with increasing number of substituents and are higher for the sulfinyl than for the sulfanyl groups.

Biologically active compounds are highly sought-after materials for developing novel structures applicable to industry. Cytosine and pyridine-2,3-dicarboxylic acid (quinolinic acid) are notably significant environmentally. Cytosine, a pyrimidine derivative, features a six-membered ring with a ketone and an amino group, constituting a fundamental nitrogenous base found in deoxyribonucleic acid (DNA). The present synthesis yielded a salt of dipyridine-2,3-dicarboxylic acid with cytosine, wherein a proton was transferred from a carboxyl group of quinolinic acid to a ring N atom in the cytosine molecule giving the salt 6-amino-2-oxo-2,3-dihydropyrimidin-1-ium 3-carboxypyridine-2-carboxylate, C₄H₆N₃O⁺·C₇H₄NO₄^-. A Hirshfeld surface analysis was conducted to examine the contribution of contacts within the salt. The structure of the salt was compared to other structures containing quinolinic acid in the Cambridge Structural Database (CSD).

This work focused on analyzing the properties of N-(5-nitrothiazol-2-yl)furan-2-carboxamide (C₈H₅N₃O₄S, NTFC) as a possible inhibitor of the rheumatoid arthritis process. The synthesis of NTFC was carried out and good-quality crystals were obtained and studied by NMR (¹H and ¹³C), DEPT 135, UV-Vis, IR, MS and single-crystal X-ray diffraction. The structure of NTFC consists of two rings, thiazole and furan, and a central C-N-C(=O)-C segment, which appears to be planar. This central amide segment forms angles of 2.61 (10) and 7.97 (11)° with the planes of the thiazole and furan rings, respectively. The crystal structure of NTFC exhibits N-H...N, N-H...O and C-H...O hydrogen bonds, and C-H...π and π-π interactions that facilitate self-assembly and the formation of hydrogen-bonded dimers, which implies the appearance of R₂²(8) graph-set motifs in this interaction. The stability of the dimeric unit is complemented by the formation of strong intramolecular C-S...O interactions of chalcogen character, with an S...O distance of 2.6040 (18) Å. Hirshfeld surface (HS) analysis revealed that O...H/H...O interactions were dominant, accounting for 36.8% of the total HS, and that N-H...N interactions were fundamental to the formation of the dimeric structure. The molecular electrostatic potential (MEP) map showed a maximum energy of 46.73 kcal mol^-1 and a minimum of -36.06 kcal mol^-1. The interaction energies of molecular pairs around NTFC are highest for those interactions linked by N-H hydrogen bonds. The properties of the NTFC ligand as a potential inhibitor of the DHODH (dihydroorotate dehydrogenase) enzyme were evaluated by molecular docking, showing coupling energies very close to those obtained with the control drug for rheumatoid arthritis, i.e. leflunomide.

2,4,6-Triaminopyrimidine is an interesting and challenging molecule due to the presence of multiple hydrogen-bond donors and acceptors. Its noncovalent interactions with a variety of carboxylic acids provide several supramolecular aggregates with frequently occurring molecular synthons. The present work focuses on the supramolecular interactions of 2,4,6-triaminopyrimidinium 3-(indol-3-yl)propionate-3-(indol-3-yl)propionic acid (1/1), C₄H₈N₅⁺·C₁₁H₁₀NO₂^-·C₁₁H₁₁NO₂, (I), 2,4,6-triaminopyrimidinium 2-(indol-3-yl)acetate, C₄H₈N₅⁺·C₁₀H₈NO₂^-, (II), 2,4,6-triaminopyrimidinium 5-bromothiophene-2-carboxylate, C₄H₈N₅⁺·C₅H₂BrO₂S^-, (III), and 2,4,6-triaminopyrimidinium 5-chlorothiophene-2-carboxylate, C₄H₈N₅⁺·C₅H₂ClO₂S^-, (IV). All four salts exhibit robust homomeric and heteromeric R₂²(8) ring motifs. Salts (I) and (II) develop sextuple [in (I)] and quadruple [in (I) and (II)] hydrogen-bonded arrays through fused-ring motifs. Salt (II) exhibits a rosette-like architecture. Salt (IV) is isostructural and isomorphous with salt (III), exhibiting an identical crystal structure with a different composition and an identical supramolecular architecture. In salts (III) and (IV), a linear hetero-tetrameric motif is formed and, in addition, both salts exhibit halogen-π interactions which enhance the crystal stability. All four salts develop a supramolecular hydrogen-bonded pattern facilitated by several N-H...O and N-H...N hydrogen bonds with multiple furcated donors and acceptors.

The introduction of the cerium(III) analogue (1-Ce, Ln = Ce) of (tert-butoxido)chloridopentakis(tetrahydrofuran)lanthanide(III) tetraphenylborate tetrahydrofuran disolvate, [Ln{OC(CH₃)₃}Cl(C₄H₈O)₅][B(C₆H₅)₄]·2C₄H₈O or [Ln(O^tBu)Cl(THF)₅](BPh₄)·2THF (1-Ln) has been achieved with a structural comparison between the existing solid-state structures of other rare earth analogues and the title compound at 100 and 180 K. The cation in 1-Ce is targeted as the cerium(III) ion possesses the criteria to exhibit slow magnetic relaxation in axial point-charge crystal fields, akin to the dysprosium(III) ion in 1-Dy. AC magnetic susceptibility experiments reveal no such behaviour for 1-Ce, putting the viability of cerium-based SMMs into question.

Three salts, namely, 2,4,6-triaminopyrimidin-1-ium sorbate dihydrate, C₄H₈N₅⁺·C₆H₇O₂^-·2H₂O, (I), 2,4,6-triaminopyrimidin-1-ium N-phenylanthranilate, C₄H₈N₅⁺·C₁₃H₁₀NO₂^-, (II), and 2,4,6-triaminopyrimidin-1-ium p-toluenesulfonate, C₄H₈N₅⁺·C₇H₇O₃S^-, (III), were synthesized, characterized by X-ray diffraction techniques and their supramolecular interactions investigated. In all three crystal structures, protonation of the pyrimidine moiety occurs at the N1 position and is reflected in a widening of the C-N-C bond angle. In salts (I)-(III), the primary acid-base interaction occurs through a pair of N-H...O hydrogen bonds to give a heterodimeric R₂²(8) synthon. Salts (II) and (III) form a discrete centrosymmetric base pair that produces a homodimeric R₂²(8) synthon and salt (I) forms a water-mediated base pair resulting in a tetrameric R₄⁴(12) synthon. The supramolecular patterns exhibited by sulfonate salt (III) mimic the patterns of carboxylate salt (II) and both exhibit a DADA array (D = donor and A = acceptor) quadruple hydrogen-bonded pattern. The crystal structures of salts (I) and (III) are stabilized by offset and face-to-face aromatic π-π stacking interactions, respectively. The resulting architectures in salts (I)-(III) are a supramolecular sheet with a rosette-like architecture in (I), a supramolecular sheet-like architecture in (II) and a three-dimensional supramolecular network in (III).