4,4′‐Di­bromo­benzo­phenone at 293 and 103 K

The structure of 4,4′‐di­bromo­benzo­phenone, C₁₃H₈Br₂O, was determined at two different temperatures (293 and 103 K). A phase transition was not detected in this temperature range. Its crystal structure was found to be isostructural with that of the di­iodo analogue, but not with the structure of the di­chloro derivative.     

5,8‐Di­methoxy‐2,3‐bis(2‐pyridyl)­quinoxaline

In the crystal structure of the title compound, C₂₀H₁₆N₄O₂, the two pyridine rings subtend dihedral angles of 39.0 (1) and 43.4 (2)° with the mean quinoxaline plane and 67.6 (1)° with each other. The orientation of the pyridine rings is such that their N‐donors face each other (cis–cis conformation) with a separation of 3.169 (2) Å. There exist significant π–π interactions responsible for the formation of stacks along the crystallographic a axis of the crystal.     

Di­bromo­[(–)‐sparteine‐κ2N,N′]­zinc(II)

In the title compound, di­bromo­[(6R,7S,8S,14S)‐1,3,4,7,7a,8,9,10,11,13,14,14a‐dodeca­hydro‐7,14‐methano‐2H,6H‐dipyrido­[1,2‐a:1′,2′‐e][1,5]­diazo­cine‐κ²N,N′]­zinc(II), [ZnBr₂(C₁₅H₂₆N₂)], the chiral nitro­gen‐chelating alkaloid (?)‐l ‐sparteine acts as a bidentate ligand, with two bromide ligands occupying the remaining coordination sites, producing a slightly distorted tetrahedral structure. The dihedral angle between the N—Zn—N and Br—Zn—Br planes is 82.4 (1)°. The distortion of the tetrahedral coordination is demonstrated by the fact that the midpoint of the N?N line does not lie in the Br—Zn—Br plane, but is tilted towards one of the N atoms by 0.164 Å. Similarly, the midpoint of the Br?Br line is tilted towards one of the Br atoms by 0.117 Å.     

2,6‐Di­phenyl­pyridine‐4‐carboxyl­ic acid

The distinctive feature of the crystal structure of 2,6‐di­phenyl­pyridine‐4‐carboxyl­ic acid, C₁₈H₁₃NO₂, is the formation of intermolecular O—H?O hydrogen bonds that lead to the formation of centrosymmetric cyclic dimers with R(8) topology. Molecules related by translation along the b axis exhibit strong π–π stacking of aromatic rings, with an average interplanar distance of 3.3 Å.     

(1R*,2R*)‐1,2‐(2,3‐Di­methoxy­butane‐2,3‐dioxy)cyclo­hexane

The title compound, 2,3‐di­methoxy‐2,3‐di­methyl‐5,6,7,8‐tetra­hydro‐4‐oxa­chroman, C₁₂H₂₂O₄, was synthesized as a model compound for substituted diequatorial fixed vicinal trans‐cyclo­hexane­diols.     

Secondary interactions in 3‐bromo­pyridinium tri­bromo­acetate

The title compound, C₅H₅BrN⁺·C₂Br₃O₂⁻, crystallizes with Z′ = 2. The residues pack in two distinct (but interconnected) types of layer, namely, layers parallel to (102), in which the residues are connected by classical N—H⋯O hydrogen bonds, C—H⋯O interactions and Br⋯Br contacts, and anion layers parallel to the ab plane, connected by Br⋯O interactions. The two formula units are topologically equivalent with respect to all these contacts.     

5,6‐Di­phenyl­thieno­[2,3‐d][1,3]dithiole‐2‐thione

The title compound, C₁₇H₁₀S₄, has two independent mol­ecules in the asymmetric unit. In both mol­ecules, the fused heterocycle is almost planar and the phenyl groups make dihedral angles of 42.88 (9) and 52.79 (8)° with the fused heterocycle in one mol­ecule, and angles of 40.62 (9) and 52.28 (8)° in the other. The crystal packing is governed by short intermolecular S?S interactions, the shortest contact being 3.333 (1) Å.     

2,4‐Di­methoxy­benzoic acid and 2,5‐di­methoxy­benzoic acid

The title compounds (both C₉H₁₀O₄) have nearly planar structures, and the methyl and/or carboxylic acid groups lie out of the molecular plane, as dictated by steric interactions. 2,5‐Di­methoxy­benzoic acid (2,5‐DMBA) forms an unusual intramolecular hydrogen bond between the carboxylic acid group and the O atom of the methoxy group in the 2‐position [O⋯O = 2.547 (2) Å and O—H⋯O = 154 (3)°]. 2,4‐DMBA forms a typical hydrogen‐bond dimer with a neighboring mol­ecule.     

2,6‐Di­phenylthiapyran‐4‐one

In the title compound, 2,6‐di­phenyl­thia­cyclo­hexan‐4‐one, C₁₇H₁₆OS, mirror site symmetry is retained by the mol­ecule in the solid state in the absence of C—H?X hydrogen bonds. The crystal structure is stabilized by van der Waals interactions, the shortest S?O and C?O contacts being 3.567 (2) and 3.512 (3) Å, respectively.     

Di­bromo­tetra‐μ3‐methoxo‐di‐μ2‐methoxo‐hexakis­(tetra­hydro­furan‐d8)­tetramagnesium

The crystal structure of the title compound, [Mg₄Br₂(CH₃O)₆(C₄D₈O)₆], consists of discrete mol­ecules with imposed symmetry C_i. The tetranuclear compound exhibits two crystallographically independent Mg atoms having distorted octahedral and trigonal–bipyramidal ­coordination spheres. The Mg atoms are bridged by two μ₃‐OMe and four μ₂‐OMe ligands, and their coordination is completed by two terminal Br and six tetra­hydro­furan ligands.     

1,2‐Di­benzoyl­hydrazine

In the crystal structure of the title compound, C₁₄H₁₂N₂O₂, the molecule lies about a twofold axis; two carbonyl groups and the H atoms of the N—N bond are in a trans orientation with respect to each other. In the crystal, each mol­ecule is linked to the other and viceversa by intermolecular N—H?O hydrogen bonds between the amide hydrogen and the O atoms of neighbouring mol­ecules to form two ten‐membered rings, each of which has the graph‐set motif C4R(10). This extends as a polymeric chain along the c axis.     

2,6‐Di­iodo­pyridine

The title compound, C₅H₃I₂N, crystallizes in the polar space group Fmm2, with crystallographic mm2 symmetry imposed on the mol­ecule. Mol­ecules are linked through C—H?N hydrogen bonding to form chains which are, in turn, joined through weak I?I halogen‐bonding interactions to form layers. The pyridine ring lies parallel to the polar z axis and has the N atom pointing in the +z direction. The layers stack in a polar fashion normal to the a axis and the absolute structure has been determined.     

Bis(2,6‐di­amino‐3,5‐di­bromo­pyridinium) tetra­bromo­cuprate(II)

The title compound, (C₅H₆Br₂N₃)₂[CuBr₄], contains isolated substituted pyridinium cations and [CuBr₄]^2? anions. The di­amino­di­bromo­pyridinium ions are planar, while the Cu^II ions have a distorted compressed tetrahedral coordination with C₂ symmetry. The two independent trans‐Br—Cu—Br angles are 128.9 (1) and 136.0 (1)°, with Cu—Br distances of 2.3939 (15) and 2.3790 (16) Å.     

4,8‐Di­methoxy‐1‐naphthalene­methanol

The title compound, C₁₃H₁₄O₃, crystallized in the centrosymmetric space group C2/c with one mol­ecule as the asymmetric unit. Each hydroxyl O atom is involved in hydrogen bonds with two other hydroxyl O atoms. The resulting chains of interactions propagate along [001]. In these interactions, the hydroxyl H atoms are disordered and the O?O distances are 2.648 (2) and 2.698 (2) Å. Two leading intermolecular C—H?O interactions have H?O distances of 2.80 and 2.84 Å and C—H?O angles of 136 and 144°; these interactions form chain and ring patterns. Taken together with the hydrogen bonds, they result in a three‐dimensional network.     

Two succinic acid derivatives of 2‐ethyl‐6‐methylpyridin‐3‐ol

Crystals of bis(2‐ethyl‐3‐hydroxy‐6‐methylpyridinium) succinate–succinic acid (1/1), C₈H₁₂NO⁺·0.5C₄H₄O₄²⁻·0.5C₄H₆O₄, (I), and 2‐ethyl‐3‐hydroxy‐6‐methylpyridinium hydrogen succinate, C₈H₁₂NO⁺·C₄H₅O₄⁻, (II), were obtained by reaction of 2‐ethyl‐6‐methylpyridin‐3‐ol with succinic acid. The succinate anion and succinic acid molecule in (I) are located about centres of inversion. Intermolecular O—H...O, N—H...O and C—H...O hydrogen bonds are responsible for the formation of a three‐dimensional network in the crystal structure of (I) and a two‐dimensional network in the crystal structure of (II). Both structures are additionally stabilized by π–π interactions between symmetry‐related pyridine rings, forming a rod‐like cationic arrangement for (I) and cationic dimers for (II).     

rac‐5‐Diphenylacetyl‐2,2,4‐trimethyl‐2,3,4,5‐tetrahydro‐1,5‐benzothiazepine and rac‐5‐formyl‐2,2,4‐trimethyl‐2,3,4,5‐tetrahydro‐1,5‐benzothiazepine

rac‐5‐Diphenylacetyl‐2,2,4‐trimethyl‐2,3,4,5‐tetrahydro‐1,5‐benzothiazepine, C₂₆H₂₇NOS, (I), and rac‐5‐formyl‐2,2,4‐trimethyl‐2,3,4,5‐tetrahydro‐1,5‐benzothiazepine, C₁₃H₁₇NOS, (II), are both characterized by a planar configuration around the heterocyclic N atom. In contrast with the chair conformation of the parent benzothiazepine, which has no substituents at the heterocyclic N atom, the seven‐membered ring adopts a boat conformation in (I) and a conformation intermediate between boat and twist‐boat in (II). The molecules lack a symmetry plane, indicating distortions from the perfect boat or twist‐boat conformations. The supramolecular architectures are significantly different, depending in (I) on C—H...O interactions and intermolecular S...S contacts, and in (II) on a single aromatic π–π stacking interaction.     

2,3‐Difluoro‐4‐formyl­phenyl­boronic acid

The mol­ecule of the title compound, 2,3‐F₂‐4‐(CHO)C₆H₂B(OH)₂ or C₇H₅BF₂O₃, contains a formyl group coplanar with the benzene ring. The boronic acid group is twisted with respect to the benzene ring plane. The mol­ecules are organized into infinite chains via inter­molecular O—H⋯O hydrogen bonds. These chains are additionally connected via strong O—H⋯O hydrogen bonds, producing a folded layer structure perpendicular to the a axis. These layers are paired due to B⋯F inter­actions.     

rac‐Eudesm‐7(11)‐en‐4‐ol

The isolation and structural determination of rac‐eudesm‐7(11)‐en‐4‐ol, C₁₅H₂₆O, from the steam distillate of the flowers of Dipterocarpus cornutus Dyer (Dipterocarpaceae) is described. The structure was determined from spectroscopic data and a single‐crystal X‐ray study. Two similar independent mol­ecules comprise the asymmetric unit of the structure.     

4,5‐Di­azafluoren‐9‐one benzoyl­hydrazone monohydrate

The title compound, C₁₈H₁₂N₄O·H₂O, adopts the keto tautomeric form and the azomethine C=N double bond is in the E configuration. The dihedral angle between the planes of the di­aza­fluorene moiety and the phenyl ring is 11.3 (1)°. In the solid state, the mol­ecules form infinite chain‐like structures via O—H?N hydrogen bonds involving the water mol­ecules and di­aza­fluorene moieties.     

N,N′‐Butane‐1,4‐diylbis­(bromo­acetamide)

The title compound, C₈H₁₄Br₂N₂O₂, lies about an inversion centre and adopts a pleated conformation, with the C(O)—NH—CH₂—CH₂ and NH—CH₂—CH₂—CH₂ torsion angles of the butane­diamine residue being −89.5 (6) and −62.1 (7)°, respectively. These data are useful in discerning the structure of polymers containing such a unit. A skew conformation is found for the Br—CH₂—C(O)—NH torsion angle [−124.2 (4)°]. The mol­ecular packing is stabilized by strong hydrogen bonds between amide groups and also by weak CH₂⋯OC inter­actions. In this way, each mol­ecule inter­acts with its six closest neighbours through eight hydrogen bonds.