Crystal structure and Hirshfeld surface analysis of 2-{[(E)-(3-cyclobutyl-1H-1,2,4-triazol-5-yl)imino]methyl}phenol

The title compound, C13H14N4O, was developed using the reaction of salicylaldehyde and 3-amino-5-cyclobutyl-1,2,4-triazole in ethanol under microwave irradiation. This eco-friendly microwave-promoted method proved to be efficient in the synthesis of 2-{[(E)-(3-cyclobutyl-1H-1,2,4-triazol-5-yl)imino]methyl}phenol in good yields and purity. The title compound is a Schiff base that exists in the phenol–imine tautomeric form and adopts an E configuration. The three independent molecules in the asymmetric unit (A, B and C) are not planar, the cyclobutyl and the phenol-imine rings are twisted to each other making a dihedral angle of 67.8 (4)° in molecule A, 69.1 (2)° in molecule B and 89.1 (2)° in molecule C. In each molecule an intramolecular O—H...N hydrogen bond is present, forming an S(6) ring motif. A Hirshfeld surface analysis was performed to investigate the contributions of the different intermolecular contacts within the supramolecular structure. The major interactions are H...H (53%), C...H (19%) and N...H (17%) for molecule A, H...H (50%), N...H (20%) and C...H (20%) for molecule B and H...H (57%), C...H (14%) and N...H (13%) for molecule C.

Bis(2,4-dioxopentan-3-ido-κ2 O,O′)dioxidomolybdenum(VI): a redetermination

The title compound, [Mo(C5H7O2)2O2] or cis-[MoO2(acac)2] (acac is acetylacetonate), contains a molybdenum(VI) atom coordinated by two acetylacetonate ligands and two doubly bonded oxido ligands in a distorted octahedral shape. The molecule is chiral and the asymmetric unit contains two independent molecules (one Δ, one Λ). Extensive C—H...O contacts are present throughout the structure. Data were collected at 100 K, providing higher precision of unit-cell parameters and atomic positions than previous determinations [Kamenar et al. (1973). Cryst. Struct. Commun. 2, 41–44.; Krasochka et al. (1975). Zh. Strukt. Khim. 16, 696–698].

Crystal structure, Hirshfeld surface and photophysical analysis of 2-nitro-3-phenyl-9H-carbazole

The title compound, C18H12N2O2, was synthesized from a dinitrobiphenylbenzene derivative using a novel modification of the Cadogan reaction. The reaction has several possible ring-closed products and the title compound was separated as the major product. The X-ray crystallographic study revealed that the carbazole compound crystallizes in the monoclinic P\overline{1} space group and possesses a single closed Cadogan ring. There are two independent molecules in the asymmetric unit. In the crystal, the molecules are linked by N—H...O hydrogen bonding.

Synthesis and crystal structure of 1-hydroxy-8-methyl-9H-carbazole-2-carbaldehyde

Two crystallographically independent molecules are present in the asymmetric unit of the title compound, C14H11NO2, with virtually identical geometries. The carbazole units are planar. The hydroxy group at position 1, carbaldehyde group at position 2, and methyl group at position 8 (with the exception of two H atoms) are coplanar with the attached benzene rings. The dihedral angle between the two benzene rings is 2.20 (9)° in molecule A and 2.01 (9)° in molecule B. The pyrrole ring makes dihedral angles of 0.82 (10) and 1.40 (10)° [0.84 (10) and 1.18 (10)° in molecule B] with the (–CH3)-substituted and (–OH and –CHO) substituted benzene rings, respectively. The molecular structure is stabilized by the intramolecular O—H...O hydrogen bonds, while the crystal structure features N—H...O and C—H...O hydrogen bonds. A range of π–π contacts further stabilizes the crystal structure.

Synthesis and Structural Characterization of Isostructural 4-(4-Aryl)-2-(5-(4-fluorophenyl)-3-(1-(4-fluorophenyl)-5-methyl-1H-1,2,3-triazol-4-yl)-4,5-dihydro-1H-pyrazol-1-yl)thiazoles

4-(4-Chlorophenyl)-2-(5-(4-fluorophenyl)-3-(1-(4-fluorophenyl)-5-methyl-1H-1,2,3-triazol-4-yl)-4,5-dihydro-1H-pyrazol-1-yl)thiazole (4) and 4-(4-fluorophenyl)-2-(5-(4-fluorophenyl)-3-(1-(4-fluorophenyl)-5-methyl-1H-1,2,3-triazol-4-yl)-4,5-dihydro-1H-pyrazol-1-yl)thiazole (5) have been synthesized in high yields. Crystallization of 4 and 5 from dimethylformamide solvent produced samples suitable for structure determination by single crystal diffraction. The materials are isostructural with triclinic, PĪ and symmetry and comprise two independent molecules in the asymmetric unit. The two independent molecules in the asymmetric unit assume similar conformation. The molecule is essentially planar apart from one of the two fluorophenyl groups, which is oriented roughly perpendicular to the plane of the rest of the molecule.

Phase behaviour and crystal structures of 2′,3′-difluorinated p-terphenyl derivatives

The crystal structures of difluorine derivatives of p-terphenyls (nTm) have been determined by single-crystal X-ray diffraction. For the unsymmetrical substituted compounds 2′,3′-difluoro-4-methyl-p-terphenyl (1T0, C19H14F2) and 4-ethyl-2′,3′-difluoro-4′′-methyl-p-terphenyl (1T2, C21H18F2), the crystal structure is disordered, with molecules statistically entering the crystal in up and down orientations, with full superposition of all the atoms, except for those of the terminal groups (H/methyl for 1T0 and methyl/ethyl for 1T2). For triclinic 2′,3′-difluoro-4,4′′-dimethyl-p-terphenyl (1T1, C20H16F2), with the space group P\overline{1}, the two crystallographically independent molecules have the same conformation, which is different from monoclinic 1T0 (space group C2) and 1T2 (space group C2/c). A common feature of the conformation of the three compounds is the noncoplanar twisted arrangement of the three rings of the p-terphenyl moiety. Two-dimensional (2D) Hirshfeld fingerprint plots are consistent with H...H and C...H contacts in the crystal packing. For the three compounds, the phase behaviour has been investigated by POM (Petra/Osiris/Molinspiration) and differential scanning calorimetry (DSC) analysis. 1T2 is mesogenic, with enantiotropic nematic behaviour.

cis-Bis(L-DOPA-κ2 N,O)copper(II) monohydrate: synthesis, crystal structure, and approaches to the analysis of pseudosymmetry

The crystal structure of the cis isomer of cis-bis(L-DOPA-κ2 N,O)copper(II) monohydrate (L-DOPA is 3,4-dihydroxy-L-phenylalanine) (CuLD), [Cu(C9H10NO4)2]·H2O, is a singular example of a structurally characterized, homoleptic, crystalline metal L-DOPA complex. CuLD crystallizes in the space group P21, with Z′ = 2. The two independent molecules are square planar, and are interconnected by a linear hydrogen-bonded chain containing 12 independent hydrogen bonds. The copper ions in both molecules have weak apical intermolecular Cu...O interactions [2.739 (2) and 2.973 (2) Å] with catechol –OH groups. A survey of the Cambridge Structural Database suggested that cis and trans isomers of Cu(NH2–C–CO2)2 amino acid complexes are equally likely to occur. 12 strong O—H...O and N—H...O hydrogen bonds stabilize an unusual linear arrangement of the Cu complexes. The Cu...Cu′ distances along the chain are nearly equal [5.0739 (3) and 5.1107 (3) Å] and the Cu...Cu′...Cu angles are nearly linear [176.75 (1)°]. The MATCH procedure available in the Oxford University Crystals for Windows package was used to carry out a detailed analysis of the relationship between the two independent molecules. MATCH has some particular advantages in studying the details of pseudosymmetry, which include: (i) no atomic-order requirements; (ii) the pseudosymmetry matrix is readily available, which allows quick insight into the symmetry elements involved and their location; and (iii) the differences between molecular centroids, as well as between all atomic positions and torsion angles, are listed. A tutorial presentation is designed to attract new users to the technique. In the present case, a search for a pseudosymmetric relationship between the two independent molecules showed that they are related by a pseudo-42 axis along the crystallographic c direction. A detailed analysis shows that the pseudo-42 symmetry is disrupted by torsions about the CH2—C(ipso) bonds, and that there is no supergroup that can be used to describe the crystal structure.