Inclusion compounds of 2,5‐di­phenyl­hydro­quinone

The crystal structures of three 1:2 inclusion compounds that consist of host mol­ecule 2,5‐di­phenyl­hydro­quinone (C₁₈H₁₄O₂) and the guest mol­ecules 2‐pyridone (C₅H₅NO), 1,3‐di­phenyl‐2‐propen‐1‐one (chalcone, C₁₅H₁₂O) and 1‐(4‐meth­oxy­phenyl)‐3‐phenyl‐2‐propen‐1‐one (4′‐methoxy­chal­cone, C₁₆H₁₄O₂) were determined in order to study the ability of guest mol­ecules in inclusion compounds to undergo photoreaction. All of the crystals were found to be photoresistant. The three inclusion compounds crystallize in triclinic space group . In each case, the host/guest ratio is 1:2, with the host mol­ecules occupying crystallographic centers of symmetry and the guest mol­ecules occupying general positions. The guest mol­ecules in each of the inclusion compounds are linked to the host mol­ecules by hydrogen bonds. In the inclusion compound where the guest mol­ecule is pyridone, the host mol­ecule is disordered so that the hydroxy groups are distributed between two different sites, with occupancies of 0.738 (3) and 0.262 (3). The pyridone mol­ecules form dimers via N—H⋯O hydrogen bonds.     

4‐[Bis(1,5‐dimethyl‐1H‐pyrazol‐3‐yl­meth­yl)­amino]phenol monohydrate

The crystal structure of the title compound, C₁₈H₂₃N₅O·H₂O, shows mol­ecules containing a phenol group linked perpendicularly to a roughly planar fragment comprising two pyrazole rings. Mol­ecules are stacked perpendicular to the [101] direction, with their phenol groups disposed alternately. The mol­ecular packing in the crystal is stabilized by hydrogen bonding involving water mol­ecules.     

1,8,14,20‐Tetra­oxa‐11,23‐dithia­tricyclo­[21.3.0.09,13]hexa­cosa‐9,12,21,24‐tetra­ene

Mol­ecules of the title compound, C₂₀H₂₈O₄S₂, the first compound with a tetra­oxacyclo­hexa­cosane ring to be structurally characterized, lie on crystallographic centres of inversion, but have approximate C_2h mol­ecular symmetry. The parallel thio­phene rings are almost exactly planar; the overall conformation of the mol­ecule is chair‐like. The mol­ecules have voids that could, in principle, accommodate small guest mol­ecules, although in the crystal structure access to these voids is blocked by neighbouring mol­ecules.     

(Z)‐2‐(3‐Methoxy­benzyl­idene)‐1‐aza­bicyclo­[2.2.2]octan‐3‐one

The crystal structure of the title compound, C₁₅H₁₇NO₂, contains two nearly identical but crystallographically independent mol­ecules, each with a double bond connecting an aza­bicyclic ring system to a 3‐methoxy­benzyl­idene moiety. The space group is triclinic P. The benzene ring is twisted by 18.44 (5) and 22.35 (4)° with respect to the plane of the double bond connected to the azabicyclic ring system for the two mol­ecules. In addition to C—H⋯π inter­actions, mol­ecules are held together in the solid state by van der Waals inter­actions.     

1,2,3‐Trimethoxy‐5,11‐dihydro­indolo[1,2‐b]isoquinoline‐5,11‐dione

The title compound, C₁₅H₁₉NO₅, crystallizes in the monoclinic space group P2₁/c with four mol­ecules in the asymmetric unit, which differ from each other in the orientation of their methoxy groups. Of the three methoxy groups in each molecule, one lies close to the plane of the mol­ecule and the other two have an out‐of‐plane conformation where they point in opposite directions. In the crystal structure, four different types of π‐stacks are observed and the mol­ecules pack in two different types of stacking sheets, with alternating mol­ecules A and B in one ribbon and alternating mol­ecules C and D in the other. The supramolecular structure is supported by C—H⋯O and π–π inter­actions.     

rac‐(Z)‐Ethyl 2‐bromo‐2‐[(3R,5R)‐3‐bromo‐5‐methyl­tetra­hydro­furan‐2‐yl­idene]acetate

In the title compound, C₉H₁₂Br₂O₃, a (tetra­hydro­furan‐2‐yl­idene)acetate, the double bond has the Z form. In the tetra­hydro­furan group, the relative configuration of the Br atom in the 3‐position and the methyl group in the 5‐position is anti. The compound crystallizes with two independent mol­ecules per asymmetric unit and, in the crystal structure, the individual mol­ecules are linked to their symmetry‐equivalent mol­ecules by C—H⋯O hydrogen bonds, so forming centrosymmetric hydrogen‐bonded dimers.     

A substituted EDOT precursor: diethyl 3,4‐di­hydroxy­thio­phene‐2,5‐di­carboxyl­ate

The title compound, C₁₀H₁₂O₆S, has been obtained as dark‐yellow chunk‐shaped crystals, together with the expected thin white needles. The structures of the two phases are identical. Two independent mol­ecules compose the asymmetric unit: one mol­ecule is totally planar, whereas a methyl group of the second mol­ecule points out of the plane. Each mol­ecule participates in several intra‐ and intermolecular hydrogen bonds and short contacts. The overall structure can be regarded as parallel sheets of mol­ecules. Within a sheet, mol­ecules are connected to one another in an infinite network via numerous short intermolecular contacts. Sheets are connected via hydrogen bonds and short contacts, in particular involving the methyl groups.     

2‐Hydroxy‐3‐(3‐oxobut­yl)naphthalene‐1,4‐dione

The title compound, C₁₄H₁₂O₄, forms crystals which appear monoclinic but are actually twinned triclinic. The asymmetric unit consists of two similar mol­ecules, which differ only in the conformation of the 3‐oxobutyl side chain. The mol­ecular conformation is characterized by an intra­molecular O—H⋯O hydrogen bond between the hydroxy group and the adjacent carbonyl O atom. The crystal structure is stabilized by O—H⋯O hydrogen bonds connecting the mol­ecules into zigzag chains running along the b axis.     

Comparison of conventional and synchrotron X‐ray structure deter­minations of the adduct 1,2,4,5‐tetrahydroxybenzene–2,5‐dihydroxy‐1,4‐benzoquinone (1/1) and a conventional X‐ray structure determination of 1,2,4,5‐tetrahydroxybenzene monohydrate

The X‐ray structure of 1,2,4,5‐tetra­hydroxy­benzene (benzene‐1,2,4,5‐tetrol) monohydrate, C₆H₆O₄·H₂O, (I), reveals columns of 1,2,4,5‐tetra­hydroxy­benzene parallel to the b axis that are separated by 3.364 (12) and 3.453 (11) Å. Molecules in adjacent columns are tilted relative to each other by 27.78 (8)°. Water mol­ecules fill the channels between the columns and are involved in hydrogen‐bonding interactions with the 1,2,4,5‐tetra­hydroxy­benzene mol­ecules. The crystal structure of the adduct 1,2,4,5‐tetra­hydroxy­benzene–2,5‐di­hydroxy‐1,4‐benzo­quinone (1/1), C₆H₆O₄·C₆H₄O₄, (II), reveals alternating mol­ecules of 1,2,4,5‐tetra­hydroxy­benzene and 2,5‐di­hydroxy‐1,4‐benzo­quinone (both lying on inversion centers), and a zigzag hydrogen‐bonded network connecting mol­ecules in three dimensions. For compound (II), the conventional X‐ray determination, (IIa), is in very good agreement with the synchrotron X‐ray determination, (IIb). When differences in data collection temperatures are taken into account, even the displacement parameters are in very good agreement.     

4‐(4‐Chloro­benzyl­ideneamino)‐1,5‐dimethyl‐2‐phenyl‐1H‐pyrazol‐3(2H)‐one and 4‐(2‐chloro­benzyl­idene­amino)‐1,5‐dimethyl‐2‐phenyl‐1H‐pyrazol‐3(2H)‐one

The two title compounds, both with formula C₁₈H₁₆ClN₃O, are structurally similar Schiff bases derived from the condensation of 4‐chloro­benzaldehyde or 2‐chloro­benzaldehyde with 4‐amino­anti­pyrine in methanol solution. As expected, both compounds adopt trans configurations about the central C=N bonds. In the crystal structure of the 4‐chloro analogue, mol­ecules are linked through weak C—H⋯O hydrogen bonds, forming chains running along the a axis. In the crystal structure of the 2‐chloro analogue, mol­ecules are linked through weak C—H⋯O and C—H⋯Cl hydrogen bonds, forming layers parallel to the ab plane.     

(4S)‐3‐[(2R,3S)‐3‐Hydr­oxy‐2‐methyl‐3‐phenyl­propion­yl]‐4‐isopropyl­oxazolidin‐2‐one

The mol­ecule of the title compound, C₁₆H₂₁NO₄, is chiral and has three asymmetric centres. The absolute configuration was not determined via diffraction measurements on the crystal, but was established from the known absolute configuration of the starting material. In the crystal structure, the mol­ecules assemble through inter­molecular hydrogen bonds into a macrostructure with helical channels.     

l‐Phenyl­alanyl‐l‐isoleucine 0.88‐hydrate

The asymmetric unit in the crystal structure of the title compound, C₁₅H₂₂N₂O₃·0.88H₂O, contains two peptide mol­ecules with completely different conformations. The structure is divided into hydro­phobic and hydro­philic layers, with channels of water mol­ecules at the layer interface.     

2,5‐Di‐2‐thienyl­thia­zolo­[4,5‐d]­thia­zole

The mol­ecules of the title compound, C₁₂H₆N₂S₄, lie on centres of symmetry. The thio­phene and thia­zole rings are almost planar and their planes make a dihedral angle of 1.68 (8)°. In the crystal structure, there is a relatively short intermolecular S⋯S contact distance of 3.5786 (9) Å.     

R(30) rectangular rings in 2,5‐dioxopiperazine‐1,4‐di­acetic acid

Molecules of the title 2,5‐dioxopiperazinedione derivative, C₈H₁₀N₂O₆, occupy centres of symmetry in the crystal structure. The six‐membered ring has an almost planar conformation, with the substituent on nitrogen nearly perpendicular to the ring. The ideal geometry of the isolated mol­ecule, as determined by ab initio HF–LCAO quantum‐mechanical calculations, is slightly more puckered than that observed in the solid state. In the crystal structure, a strong hydrogen bond joins neighbouring mol­ecules, thus forming a network of rectangular (30) rings.     

Disodium 2,5‐bis(phenylamino)terephthalate deca­hydrate,an inter­mediate in the industrial synthesis of quinacridone pigments

The title compound, 2Na⁺·C₂₀H₁₄N₂O₄²⁻·10H₂O, is an inter­mediate in the industrial synthesis of red and violet quinacridone pigments. The structure is remarkable for two reasons. First, one of the Na⁺ ions is surrounded octa­hedrally by five water mol­ecules and a phenyl group, although the crystal contains many more water mol­ecules than are required for complete coordination of both Na⁺ ions with six water mol­ecules each. Secondly, although the anion has almost exact mol­ecular inversion symmetry, it is positioned on a general position; this is one of the very few exceptions to the observation of Kitajgorodskij [Advances in Structure Research by Diffraction Methods–Fortschritte der Strukturforschung mit Beugungsmethoden (1970), Vol. 3, pp. 173–247] that mol­ecules with inversion centres always lie on crystallographic inversion centres.     

1,3,5,7‐Tetraselena‐2,4,6,8(2,5)‐tetrathiophenaoctaphane

The novel title tetraselenacalix[4]arene, C₁₆H₈S₄Se₄ or [(C₄H₂S)Se]₄, has a centrosymmetric cyclic molecular structure with approximate C_2h molecular symmetry. The four thienyl rings are joined together by Se bridges and exhibit a syn–syn–anti–anti arrangement around the mol­ecule. The lattice consists of skewed stacks of mol­ecules, with chalcogen–chalcogen close contacts binding the stacks together, forming a two‐dimensional network of mol­ecules.     

trans‐4‐Bromo‐ONN‐azoxy­benzene at 100 K

The crystal structure of the α isomer of trans‐4‐bromo­azoxy­benzene [systematic name: trans‐1‐(bromophenyl)‐2‐phenyl­diazene 2‐oxide], C₁₂H₉BrN₂O, has been determined by X‐ray dif­frac­tion. The geometries of the two mol­ecules in the asymmetric unit are slightly different and are within ∼0.02 Å for bond lengths, ∼2° for angles and ∼3° for torsion angles. The azoxy bridges in both mol­ecules have the typical geometry observed for trans‐azoxy­benzenes. The crystal network contains two types of planar mol­ecules arranged in columns. The torsion angles along the Ar—N bonds are only 7 (2)°, on either side of the azoxy group.     

Naphthalene‐1,7‐diol

The asymmetric unit of the title compound, C₁₀H₈O₂, contains two planar symmetry‐independent mol­ecules linked by an O—H⋯O hydrogen bond. In the crystal structure, mol­ecules are linked into infinite chains of rings, formed by a combination of O—H⋯O and C—H⋯O hydrogen bonds, and additionally reinforced by π–π stacking inter­actions. Adjacent chains are connected by weak C—H⋯π inter­actions.     

2‐Anilinomethyl­ene‐3‐oxobutane­nitrile: an X‐ray and density functional theory study

Mol­ecules of the title compound, C₁₁H₁₀N₂O, are effectively planar. In the crystal structure, they are stabilized primarily by electrostatic inter­actions, as the dipole moment of the mol­ecule is 4.56 D. In addition, the mol­ecules are linked by weak C—H⋯N and C—H⋯O hydrogen bonds. An analysis of bonding conditions in the mol­ecule was carried out using natural bond orbital (NBO) formalism.     

4‐Bromo‐2‐{[4‐(3‐mesityl‐3‐methyl­cyclo­butyl)thia­zol‐2‐yl]hydrazono­meth­yl}phenol,with N—H⋯N,C—H⋯π and π–π inter­actions

The title compound, C₂₄H₂₆BrN₃OS, crystallizes in the triclinic space group P, with two independent mol­ecules in the asymmetric unit. The mol­ecules adopt an E geometry about the azomethine C=N double bond. The structure is stabilized as dimers by N—H⋯N hydrogen bonding. C—H⋯π and π–π inter­actions are also effective in the crystal packing.