Crystal structure of 2-{[5-amino-1-(phenylsulfonyl)-1H-pyrazol-3-yl]oxy}-1-(4-methylphenyl)ethan-1-one

In the title compound, C18H17N3O4S, the pyrazole ring is planar, with the sulfur atom lying 0.558 (1) Å out of the ring plane. The NH2 group is involved in an intramolecular hydrogen bond to a sulfonyl oxygen atom; its other hydrogen atom forms an asymmetric three-centre hydrogen bond to the two oxygen atoms of the —O—CH2—C=O— grouping, via the 21 screw axis, forming a ribbon structure parallel to the b axis. Translationally adjacent, coplanar ribbons form a layer parallel to (10\overline{4}).

2-Chloro-3-nitro-5-(trifluoromethyl)benzoic acid and -benzamide: structural characterization of two precursors for antitubercular benzothiazinones

8-Nitro-1,3-benzothiazin-4-ones are a promising class of new antitubercular agents, two candidates of which, namely BTZ043 and PBTZ169 (INN: macozinone), have reached clinical trials. The crystal and molecular structures of two synthetic precursors, 2-chloro-3-nitro-5-(trifluoromethyl)benzoic acid, C8H3ClF3NO4 (1), and 2-chloro-3-nitro-5-(trifluoromethyl)benzamide, C8H4ClF3N2O3 (2), are reported. In 1 and 2, the respective carboxy, carboxamide and the nitro groups are significantly twisted out of the plane of the benzene ring. In 1, the nitro group is oriented almost perpendicular to the benzene ring plane. In the crystal, 1 and 2 form O—H...O and N—H...O hydrogen-bonded dimers, respectively, which in 2 extend into primary amide tapes along the [101] direction. The trifluoromethyl group in 2 exhibits rotational disorder with an occupancy ratio of 0.876 (3):0.124 (3).

On the aromaticity of uracil and its 5-halogeno derivatives as revealed by theoretically derived geometric and magnetic indexes

The problem of aromaticity in heterocyclic rings of uracil and its 5-halogenoderivatives (5XU) was analyzed theoretically by calculating modified harmonic oscillator model of aromaticity (HOMA) for Heterocycle Electron Delocalization (HOMHED), nucleus-independent chemical shift parameters (NICS) and the so-called scan experiments, using helium-3 atom as a magnetic probe. The impact of halogen electronegativity on C5 atom’s NBO charges was also investigated. Water, as a polar environment, has a negligible impact on 5XU aromaticity. The most stable diketo tautomer shows a very low aromaticity while the “rare” dihydroxy form (tautomer No 6) is aromatic and resembles benzene. This is in agreement with traditional drawing of chemical formula of uracil’s six-membered ring, directly showing three alternating single and double bonds in its tautomer No 6. No good correlation between magnetic and geometric indexes of aromaticity for the studied 5XU tautomers was found. Linear correlation between the magnitude of NICS minimum, as well as the distance of the minimum above uracil ring plane center from 3He NMR chemical shift scan plot with respect to halogen electronegativity were observed. A strong linear dependence of magnetic index of aromaticity and the electronegativity of 5X substituent was observed.

N-(4-Ethoxy-2,5-dinitrophenyl)acetamide

In the title compound, C10H11N3O6, the torsion angles about the bonds to the benzene ring are less than 4°, except for the nitro groups, which are twisted out of the ring plane by 25.27 (3) and 43.63 (2)°. The N—H group forms a bifurcated hydrogen bond, with an intramolecular component to a nitro group O atom and an intermolecular component to the other nitro group, thereby forming chains propagating in the [010] direction. Several weak C—H...O interactions are also present.

2,3-Diethylbenzo[g]quinoxaline

The title compound, C16H16N2, was synthesized by dispersing 3,4-hexanedione in a methanol–water solution containing the acid catalyst NH4HF2, then adding 1,2-diaminonaphthalene. The fused-ring system of the title compound is close to planar (r.m.s. deviation = 0.028 Å); one of the pendant methyl C atoms lies close to the ring plane [deviation = 0.071 (2) Å; N—C—C—C = −0.27 (18)°] whereas the other is significantly displaced [–1.7136 (18) Å; 91.64 (16)°]. The molecules pack in space group I\overline{4} in a distinctive criss-cross motif supported by numerous aromatic π–π stacking interactions [shortest centroid–centroid separation = 3.5805 (6) Å].

Anagostic Interactions in Alkyl-Fluorenyl-Substituted N‐Heterocyclic Carbene Complexes of Palladium(II)

Two imidazolylidene (Im) complexes of the general formula trans-[PdX2(Im)(pyridine)] (X=Cl (2), Br (3)), in which the N-heterocyclic carbene ligand has one of its nitrogen atoms substituted by a bulky 9-propyl-9-fluorenyl group (PrF), have been prepared and fully characterised by spectroscopic methods and single-crystal X-ray structure analyses. In the solid state, the Im ring plane and the coordination plane of each complex are nearly orthogonal, thereby minimising the steric interactions between the N-substituents and the halide atoms. In both structures two methylenic C–H bonds sit near the dz2 axis point to the palladium atom, resulting in CH⋯Pd separations of 2.58/2.95Å in 2 and 2.74/2.74Å in 3. NMR measurements and DFT calculations indicate that these methylene groups are involved in anagostic CH⋯M interactions but not in significant H⋯X bonding.

Structure and Hirshfeld surface analysis of the salt N,N,N-trimethyl-1-(4-vinylphenyl)methanaminium 4-vinylbenzenesulfonate

In the title compound, the asymmetric unit comprises an N,N,N-trimethyl-1-(4-vinylphenyl)methanaminium cation and a 4-vinylbenzenesulfonate anion, C12H18N+·C8H7O3S−. The salt has a polymerizable vinyl group attached to both the cation and the anion. The methanaminium and vinyl substituents on the benzene ring of the cation subtend angles of 86.6 (3) and 10.5 (9)° to the ring plane, while the anion is planar excluding the sulfonate O atoms. The vinyl substituent on the benzene ring of the cation is disordered over two sites with a refined occupancy ratio of 0.542 (11):0.458 (11). In the crystal, C—H...O hydrogen bonds dominate the packing and combine with a C—H...π(ring) contact to stack the cations and anions along the a-axis direction. Hirshfeld surface analysis of the salt and of the individual cation and anion components is also reported.

Crystal structure of a 1:1 adduct of triphenyltin chloride with 3-cyclohexhyl-2-phenyl-1,3-thiazolidin-4-one

In the centrosymmetric (racemic) title compound, chlorido(3-cyclohexhyl-2-phenyl-1,3-thiazolidin-4-one-κO)triphenyltin(IV), [Sn(C6H5)3Cl(C15H19NOS)], the tin(IV) atom exhibits a trigonal–bipyramidal coordination geometry with the three phenyl groups in equatorial positions and the chloride anion and ligand oxygen atom present at axial sites [O—Sn—Cl = 175.07 (14)°]. The thiazolidinone ring of the ligand adopts an envelope conformation with the S atom as the flap. The dihedral angles between the heterocycle ring plane (all atoms) are 44.3 (9)° with respect to the pendant C-phenyl plane and 34.3 (11)° to the N-cyclohexyl ring (all atoms). The C-phenyl and N-cyclohexyl ring are close to orthogonal to each other, with a dihedral angle of 81.1 (4)° between them. In the crystal, molecules are linked by weak C—H...Cl hydrogen bonds to generate [001] chains.

Structural and Thermoelectric Properties of Cu Substituted Type I Clathrates Ba8CuxSi~32−xGa~14

With an attempt to improve the thermoelectric properties of type I clathrates in the Ba-Ga-Si system, we introduce Cu into the framework of the crystal structure. Single crystals are prepared in Ga-flux and characterized by X-ray diffraction techniques and transport measurements for the structural and thermoelectric properties. Our composition analyses show that only a small amount of Cu is determined in the clathrates. The single crystal X-ray diffraction data refinements confirm that Ga atoms prefer the 6c and 24k sites and avoid the 16i sites in the crystal structure. The small amount of Cu affects the crystal structure by compressing the tetrakaidecahedral cage along the direction perpendicular to the six-atom-ring plane. This could be the reason for the high charge carrier concentration, and low electrical resistivity and Seebeck coefficient. We analyze the principal mechanism for our observation and conclude that the Cu substitution can adjust some subtle details of the structure, maintaining the Zintl rule in the type I clathrates.

Crystal structure and Hirshfeld surface analysis of 1-[(1-butyl-1H-1,2,3-triazol-4-yl)methyl]-3-methylquinoxalin-2(1H)-one

The title compound, C16H19N5O, is built up from a planar quinoxalinone ring system linked through a methylene bridge to a 1,2,3-triazole ring, which in turn carries ann-butyl substituent. The triazole ring is inclined by 67.09 (4)° to the quinoxalinone ring plane. In the crystal, the molecules form oblique stacks along thea-axis direction through intermolecular C—HTrz...NTrz(Trz = triazole) hydrogen bonds, and offset π-stacking interactions between quinoxalinone rings [centroid–centroid distance = 3.9107 (9) Å] and π–π interactions, which are associated pairwise by inversion-related C—HDhydqn...π(ring) (Dhydqn = dihydroquinoxaline) interactions. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H...H (52.7%), H...N/N...H (18.9%) and H...C/C...H (17.0%) interactions.