1,3‐Bis(4‐nitro­phenyl)­triazene

The structure of the title compound, C₁₂H₉N₅O₄, reveals an almost planar mol­ecule (r.m.s. deviation = 0.061 Å), in which the interplanar angle between the phenyl rings is 5.7 (1)° and the largest interplanar angle is that between the phenyl ring and the nitro group of one of the 4‐nitro­phenyl substituents [8.8 (3)°]. The observed mol­ecular conformation suggests a delocalization of π‐electrons extended over the diazo­amine group and the terminal aryl substituents. Intermolecular N—H⃛O interactions between the twofold screw‐related mol­ecules give rise to helical chains along the [010] direction. Intermolecular C—H⃛O interactions then generate sheets of mol­ecules in the (10) plane, and these sheets are held together by N⃛C and O⃛O π–π interactions.     

N‐(4‐Cyano­phenyl)‐α‐(4‐methoxy­phenyl)­nitro­ne

In the crystal structure of the title compound, 4‐cyano‐N‐(4‐methoxy­benzyl­idene)­phenyl­amine N‐oxide, C₁₅H₁₂N₂O₂, the 4‐methoxy­phenyl is approximately coplanar with the nitrone moiety but significantly rotated with respect to the 4‐cyano­phenyl moiety. The extent of this rotation is significantly different for the two crystallographically independent mol­ecules of the asymmetric unit [dihedral angles of 19.4 (1) and 26.5 (1)°]. The geometry about the C=N bond is Z. The two mol­ecules are related to one another by a pseudo inversion centre.     

2,2‐Di­methyl‐1‐(2,4,6‐tri­nitro­phenyl)­hydrazine

The title mol­ecule (DMPH‐H), C₈H₉N₅O₆, was investigated to provide comparison with 2,2‐di­phenyl‐1‐picryl­hydrazine, which unlike DMPH‐H is readily oxidizable to form a well known stable free radical (DPPH). The structure shows essential differences in the configuration of the hydrazine‐N atoms, the ortho‐nitro group orientations and the crystal packing. The bond angles of the di­methyl­amino N atom [107.90 (13), 108.96 (12) and 112.21 (13)°] are consistent with a tetrahedral N atom and sp³ hybridization.     

Conformational preferences in 2‐­nitrophenylthiolates: S‐(2‐nitro­phenyl) 4‐toluenethiosulfonate

In the title compound, C₁₃H₁₁NO₄S₂, the nitro group is rotated by 44.1 (1)° out of the plane of the adjacent aryl ring and the toluene­thio­sulfonate group is almost orthogonal to the plane of the nitrated aryl ring. There are three types of C—H?O hydrogen bond in the structure [C?O range 3.324 (3)–3.503 (3) Å; C—H?O range 160–173°] and these link the mol­ecules into a three‐dimensional framework.     

1‐(4‐Bromo­phenyl)‐3‐(4‐methyl­phenyl)­prop‐2‐en‐1‐one

In the mol­ecule of the title compound, C₁₆H₁₃BrO, the two benzene rings are rotated in opposite directions with respect to the central C—C=C—C part of the mol­ecule. The phenone O atom deviates from the least‐squares plane of the mol­ecule by 0.300 (3) Å. In the crystal structure, mol­ecules are paired through C—H⋯π interactions. The molecular pairs along [001] are hydrogen bonded through three translation‐related co‐operative hydrogen bonds in the `bay area', forming molecular chains, which are further hydrogen bonded through C—H⋯Br weak interactions, forming (010) molecular layers. In the third direction, there are only weak van der Waals interactions. The co‐operative hydrogen bonds in the `bay area' are discussed briefly.     

4‐[3‐(3,4‐Di­methoxy­phenyl)­prop‐2‐enoyl]­phenyl methacryl­ate and 4‐[3‐(2‐bromo­phenyl)­prop‐2‐enoyl]­phenyl methacryl­ate

Chalcones (α,β‐unsaturated ketones) are effective antitumour agents. It has been proved that having halogen or methoxy groups substituted in various positions of the phenyl ring enhances the activity of chalcones many times. The title compounds, C₂₁H₂₀O₅ and C₁₉H₁₅BrO₃, respectively, were chosen for crystallographic study in order to determine their structures and conformations. In both compounds, the keto group is in the s‐cis conformation and is almost planar. There are weak intramolecular interactions in both structures.     

Red,orange and yellow crystals of 4,5‐­bis(4‐methoxy­phenyl)‐2‐(3‐nitro­phenyl)‐1H‐imidazole

Red non‐solvate crystals of the title compound from ethanol, C₂₃H₁₉N₃O₄, orange solvate crystals from tert‐butanol, C₂₃H₁₉N₃O₄·C₄H₁₀O, yellow solvate crystals from dioxane–water, C₂₃H₁₉N₃O₄·0.5C₄H₈O₂, and intense yellow solvate crystals from benzene–N,N′‐dimethylformamide, C₂₃H₁₉N₃O₄·C₆H₆, differ from each other in their molecular conformation and hydrogen‐bonding scheme. The bathochromic shifts of the crystal color are explained by the molecular planarity and charge‐transfer effect among the imidazole mol­ecules.     

Bis[4‐(3‐pyridylmethyl­eneamino)­phenyl]methane

In the title Schiff base compound, C₂₅H₂₀N₄, the two rigid parts adopt an angular conformation, thus making the compound a potential non‐linear ditopic ligand for the construction of interesting coordination polymers.     

4‐Chloro‐N‐(4‐cyano‐2‐nitro­phenyl)‐3‐nitro­benz­amide

The structure of the title compound, C₁₄H₇ClN₄O₅, comprises two nearly coplanar phenyl rings connected via an amido moiety.     

1,3‐Bis(4‐methyl­phen­yl)triazene, 1‐(4‐chloro­phen­yl)‐3‐(4‐fluoro­phen­yl)triazene and 1‐(4‐fluoro­phen­yl)‐3‐(4‐methyl­phen­yl)triazene

The title 4,4′‐disubstituted diphen­yl‐1,3‐triazines, C₁₄H₁₅N₃, (I), C₁₂H₉ClFN₃, (II), and C₁₃H₁₂FN₃, (III), each contain a triazene group (–N=N—NH–) having an extended conformation. The dihedral angles between the two benzene rings in (I), (II) and (III) are 4.3, 3.4 and 6.5°, respectively. The mol­ecules are almost entirely planar, with maximum deviations from the mean planes of 0.1087 (2), −0.1072 (7) and 0.1401 (3) Å, respectively. In each compound, the molecules are linked by N—H⋯N hydrogen bonds to form chains and pack similarly in the crystal structures.     

3‐Butyl‐1‐(5‐nitro­benzo­[c][1,2]­thia­zol‐3‐yl)‐3‐phenyl­triazene

The mol­ecule of the title compound, C₁₇H₁₇N₅O₂S, consists of three π systems, viz. two aromatic rings and the triazene moiety, which are mutually deconjugated although coplanar. The n‐butyl chain is roughly perpendicular to the molecular plane, with the terminal methyl­ene and methyl groups disordered between two equally populated positions. The mol­ecules in the crystal associate in an antiparallel fashion, forming dimers across the centre of symmetry, the principal intradimer interaction being stacking of the π‐electron portions of the mol­ecules.     

1‐(2‐{4‐[6‐Hydro­xy‐2‐(4‐hydroxy­phenyl)­benzo­[b]­thiol‐3‐yl­carbonyl]­phenoxy}ethyl)­piperidinium chloride

The title compound, raloxifene hydro­chloride, C₂₈H₂₈NO₄S⁺·Cl^?, belongs to the benzo­thio­phene class of antiosteoporotic drugs. In the molecular cation, the 2‐phenol ring sustains a dihedral angle of 45.3 (1)° relative to the benzo­[b]­thio­phene system. The benzo­[b]­thio­phene and phenyl ring planes are twisted with respect to the carbonyl plane, with the smallest twist component occurring between the phenyl and carbonyl planes. The N atom bears the positive charge in the molecular cation and the piperidine ring adopts an almost perfect chair conformation. The Cl^? anion is involved in the formation of N—H?Cl and O—H?Cl intermolecular hydrogen bonds, which lead to the formation of a layer of molecular cations.     

trans‐Bis­[1‐methyl‐3‐(p‐nitro­phenyl)­triazenido 1‐oxide‐κ2N3,O]­di­pyridine­nickel(II)

In the centrosymmetric title complex, [Ni(C₇H₇N₄O₃)₂(C₅H₅N)₂], the coordination geometry about the Ni²⁺ ion is octahedral, with two deprotonated 1‐methyl‐3‐(p‐nitro­phenyl)­triazenide 1‐oxide ions, viz. [O₂N­C₆H₄­NNN(O)­CH₃]^?, acting as bidentate ligands (four‐electron donors). Two neutral pyridine (py) mol­ecules complete the coordination sphere in positions trans to each other. The triazenide 1‐oxide ligand is almost planar, the largest interplanar angle of 8.80 (12)° being between the phenyl ring of the p‐nitro­phenyl group and the plane defined by the N₃O moiety. The Ni—N_triazenide, Ni—O and Ni—N_py distances are 2.0794 (16), 2.0427 (13) and 2.1652 (18) Å, respectively.     

N‐[1‐(Penta­fluoro­phenyl)­ethyl]­acetamide

The title compound, C₁₀H₈F₅NO, crystallizes as a racemate with four symmetry‐independent mol­ecules in the asymmetric unit. The four mol­ecules form two hydrogen‐bonded pairs. Each pair is a building unit of an independent C(4) chain propagating parallel to the ab plane.     

Ethyl N‐[2‐(hydroxy­acetyl)­phenyl]­carbamate,ethyl N‐[2‐(hydroxy­acetyl)‐4‐iodo­phenyl]­carbamate and ethyl N‐[2‐(hydroxy­acetyl)‐4‐methyl­phenyl]­carbamate

In ethyl N‐[2‐(hydroxy­acetyl)phenyl]carbamate, C₁₁H₁₃NO₄, all of the non‐H atoms lie on a mirror plane in the space group Pnma; the mol­ecules are linked into simple chains by a single C—H⋯O hydrogen bond. The mol­ecules of ethyl N‐[2‐(hydroxy­acetyl)‐4‐iodo­phenyl]carbamate, C₁₁H₁₂INO₄, are linked into sheets by a combination of O—H⋯I and C—H⋯O hydrogen bonds and a dipolar I⋯O contact. Ethyl N‐­[2‐(hydroxy­acetyl)‐4‐methyl­phenyl]carbamate, C₁₂H₁₅NO₄, crystallizes with Z′ = 2 in the space group P; pairs of mol­ecules are weakly linked by an O—H⋯O hydrogen bond and these aggregates are linked into chains by two independent aromatic π–π stacking inter­actions.     

Bis­[3‐(o‐methoxy­phenyl)‐1‐methyl­triazene 1‐oxidato‐O,N3,O′]­zinc(II)

In the title compound, [Zn(C₈H₁₀N₃O₂)₂], the Zn atom displays a highly distorted octahedral coordination involving O and N atoms of two bidentate planar ligands approximately orthogonal to each other; the dihedral angle between the ligand planes is 84.95 (4)°. The ligand mol­ecules show great asymmetry in their bonding to the Zn²⁺ ion, with Zn—O bond distances ranging between 2.056 (2) and 2.534 (2) Å. The planar phenyl ring and the trigonal–planar geometry about the triazene N atom bonded to the phenyl ring suggest a resonance interaction extending over adjacent atoms.     

[4‐(Tri­fluoro­methyl)­phenyl]­aceto­nitrile

The crystal structure of the title compound, C₉H₆F₃N, at 123 K contains mol­ecules linked together via several C—H?F and C—H?N contacts, the strongest of which are 2.58 and 2.65 Å, respectively. Apparently, an F atom in the CF₃ group is able to compete with a cyano N atom for aromatic H atoms but is less prone to interact with the more acidic methyl­ene H atoms. The Ph–CH₂CN torsion angle is ?6.4 (2)° and the planar phenyl ring exhibits a typical deformation of the endo angles at the ipso‐C atoms, due to the difference in the electron‐withdrawing power of the CF₃ and CH₂CN substituents.     

1‐(2‐Hydro­xy‐4‐methoxy­phenyl)‐3‐(2,3,4‐tri­methoxy­phenyl)­prop‐2‐en‐1‐one

The title compound, C₁₉H₂₀O₆, crystallizes in the centrosymmetric space group P2₁/c with one mol­ecule in the asymmetric unit. The mol­ecule is approximately planar and the dihedral angle between the phenyl rings is 11.0 (1)°. The H atoms of the central propenone group are trans. There is an intramolecular O—H⃛O hydrogen bond and the mol­ecules are crosslinked by four intermolecular C—H⃛O hydrogen bonds, producing a three‐dimensional network.     

(E)‐1‐(2‐Hydro­xy‐4‐methoxy­phenyl)‐2‐(3,4,5‐tri­methoxy­phenyl)­ethene

In the crystal structure of the title compound, C₁₈H₂₀O₅, all geometric parameters fall within experimental error of the expected values. Analysis of the molecular‐packing plots reveals an infinite one‐dimensional linear array running parallel to the c axis, formed by an O—H⃛O intermolecular hydrogen‐bonding interaction. The stilbene framework and most of the substituents are approximately coplanar.     

Ethyl 2‐form­amido‐2‐(4‐iodo­benzyl)‐3‐(4‐iodo­phenyl)­propionate and ethyl 2‐(3‐bromo­benzyl)‐3‐(3‐bromo­phenyl)‐2‐form­amidopropionate

The title compounds, C₁₉H₁₉I₂NO₃ and C₁₉H₁₉Br₂NO₃, are derivatives of α‐amino­isobutyric acid with halogen substituents at the para and meta positions, respectively. The ethoxycarbonyl and formamide side chains attached to the C_α atom of the mol­ecule adopt extended and folded conformations, respectively. The crystal structures are stabilized by N—H⃛O, C—H⃛O, C—Br⃛O and C—I⃛O interactions.