(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.     

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.     

(E,E)‐2,5‐Diprop­oxy‐1,4‐bis­[2‐(2,4,6‐trimethoxy­phen­yl)ethen­yl]benzene

The title compound, C₃₀H₃₄O₈, crystallizes in the space group P with one‐half of a mol­ecule in the asymmetric unit. A three‐dimensional network is generated by OCH₃⋯π and CH⋯π inter­actions. The conformation of the C—C bond exocyclic to the central benzene ring is different from that of every other known derivative. A comparison of the geometry of the title mol­ecule and of its solid‐state structure with other 2,4,6‐trimeth­oxy‐substituted PPV [i.e. poly(p‐phenylenevinylene)] oligomers, in particular the isoprop­oxy‐substituted compound, is provided.     

Di­chloro­bis­[2‐(o‐tolyl­iminio­methyl)­phenolato‐O]­zinc(II)

In the mononuclear title compound, [ZnCl₂(C₁₄H₁₃NO)₂], the Zn^II ion is located on a twofold axis of the monoclinic space group so that the whole mol­ecule has a twofold symmetry. The Zn^II ion has a tetrahedral coordination consisting of two chlorine ions and the O atoms of the ligands. The coordination angles around zinc have values between 102.89 (8) (O—Zn—O) and 115.83 (5)° (Cl—Zn—O). The Zn—O and Zn—Cl bond lengths are 1.977 (2) and 2.2401 (7) Å, respectively. There are intra‐ and intermolecular hydrogen bonds in the structure.     

Tri­phenyl(3,4,5‐tri­iodo­phenyl)­methane

The crystal structure of the title compound, alternatively called 1,2,3‐triiodo‐5‐(triphenylmethyl)benzene, C₂₅H₁₇I₃, is analysed in terms of I⋯I and I⋯π interactions and the herring‐bone T motif between phenyl groups. There are two mol­ecules in the asymmetric unit, denoted A and B. Inversion‐related A mol­ecules are connected via an I⋯π interaction (3.641 Å, to a C—C bond mid‐point) to form an I⋯π dimer, and these dimers are connected through symmetry‐independent B mol­ecules via I⋯I [3.5571 (15) Å] and I⋯π (3.561 Å, to a C—C bond mid‐point) interactions.     

2,4‐Di­hydroxy‐1,3‐bis­(methoxy­carbonyl­methoxy)­calix­[4]­arene and 1,3‐bis­(ethoxy­carbonyl­methoxy)‐2,4‐di­hydroxy­calix­[4]­arene chloro­form solvate

The two title calix­[4]­arene compounds, C₃₄H₃₂O₈, (I), and C₃₆H₃₆O₈·CH₃Cl, (II), respectively, which differ only in the size of the alkyl function on the pendant ester group, are compared. Compound (I) forms a novel supramolecular array, whilst (II) fails to do so due to accommodating a chloro­form guest molecule in the lower‐rim cavity.     

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.     

(E)‐4‐[2‐(3,4,5‐Trimethoxyphenyl)ethenyl]nitrobenzene and its `bridge‐flipped' analogues

The solid‐state structures of three push–pull acceptor‐π‐donor (A‐π‐D) systems differing only in the nature of the π‐spacer have been determined. (E)‐1‐Nitro‐4‐[2‐(3,4,5‐trimethoxyphenyl)ethenyl]benzene, C₁₇H₁₇NO₅, (I), and its `bridge‐flipped' imine analogues, (E)‐3,4,5‐trimethoxy‐N‐(4‐nitrobenzylidene)aniline, C₁₆H₁₆N₂O₅, (II), and (E)‐4‐nitro‐N‐(3,4,5‐trimethoxybenzylidene)aniline, C₁₆H₁₆N₂O₅, (III), display different kinds of supramolecular networks, viz. corrugated planes, a herringbone pattern and a layered structure, respectively, all with zero overall dipole moments. Only (III) crystallizes in a noncentrosymmetric space group (P2₁2₁2₁) and is, therefore, a potential material for second‐harmonic generation (SHG).     

Amido­bis­[η5‐1,3‐bis­(tri­methyl­silyl)­cyclo­penta­dienyl]­titanium(III)

The title compound, [Ti(C₁₁H₂₁Si₂)₂(NH₂)], crystallizes as a bent metallocene, with the NH₂ group oriented to maximize the π interaction between the N atom and the Ti^III center. The increased π bonding is reflected in a short Ti—N bond length of 1.933 (3) Å.     

2‐Hydro­xy‐5‐[(E)‐(4‐methoxy­phenyl)­diazenyl]­benzoic acid

The title compound, C₁₄H₁₂N₂O₄, shows an E conformation about the diazenyl N atoms. The crystal structure features layers of mol­ecules with the primary connection between the layers afforded by carboxyl­ic acid dimer motifs; no evidence for extensive π–π stacking between the layers was found.     

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.     

Bis{bis­[5‐tert‐butyl‐2‐oxido‐3‐(1‐pyridinio­methyl)­phenyl]­methane}­dioxouranium bis­(tri­fluoro­methane­sulfonate) pyridine disolvate: a uranyl bis­(diphenoxide) complex resulting from homooxacalixarene cleavage

The title compound, [UO₂(C₃₃H₃₈N₂O₂)₂](CF₃SO₃)₂·2C₅H₅N, has been obtained by reaction of U^IV tri­fluoro­methane­sulfonate with p‐tert‐butyl­tetrahomodioxacalix­[4]­arene in pyridine. The uranyl ion lies on an inversion centre and is bound to two O atoms from each diphenoxide ligand, which gives the usual square‐planar equatorial environment. The zwitterionic diphenoxide species results from nucleophilic attack by pyridine on the benzylic ether C atoms of the homooxacalixarene, assisted by initial U coordination to the ether groups, with subsequent metal oxidation giving the uranyl moiety.     

trans‐Di­chloro­bis­(tri­phenyl­phosphine‐P)­platinum(II)

Two different crystals (A and B) were used to structurally characterize trans‐[PtCl₂(PPh₃)₂] and to study random and systematic errors in derived parameters. The compound is isomorphous with trans‐[PdCl₂(PPh₃)₂] and with one of the polymorphs of trans‐[PtMeCl(PPh₃)₂] reported previously. Half‐normal probability plot analyses based on A and B show realistic s.u.'s and negligible systematic errors. R.m.s. calculations give very good agreement between A and B, 0.0088 Å. Important geometrical parameters are Pt—P = 2.3163 (11) Å, Pt—Cl = 2.2997 (11) Å, P—Pt—Cl = 87.88 (4) and 92.12 (4)°. Half‐normal probability plots and r.m.s. calculations were also used to compare the title compound with the palladium analogue, showing small systematic differences between the compounds. The torsion angles around the Pt—P bond were found to be very similar to those reported for isomorphous complexes, as well as to the torsion angles around the Pt—As bond in trans‐[PtCl₂(AsPh₃)₂]. The NMR coupling constants for the title compound are similar to Pt—P coupling constants reported for analogous trans complexes.     

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)‐ and {(Z)‐2‐[α,β‐bis­(methoxy­carbonyl)­vinyl]­cyclo­pentadien‐1‐yl­idene}tri­phenyl­phospho­rane

The Ramirez yl­ide undergoes electrophilic substitution with di­alkyl acetyl­ene­di­carboxyl­ates, yielding a mixture of the Z and E adducts. The crystal structure analyses of the two adducts formed using di­methyl­acetyl­ene, viz. di­methyl (E)‐ and (Z)‐1‐[2‐(tri­phenyl­phospho­ranyl­idene)­cyclo­pentadien‐1‐yl]­ethyl­ene­di­carboxyl­ate, both C₂₉H₂₅O₄P, explain an unusual chemical shift observed for the vinyl H atom of the Z adduct, which had previously precluded a definitive assignment of the isomers. In addition, the structures explain why only one of the isomers reacts further with acetyl­ene esters to produce azulenes with a rare substitution pattern.     

3,3‐Bis(2‐methoxy­phenyl)‐3H‐benzo­[f]­chromene

The substituent methoxy group at the phenyl ortho position in the title compound, C₂₇H₂₂O₃, has an insignificant effect on the length of the Csp³—O bond and on the non‐planarity of the pyran ring. The cause of the changes in the photochemical properties is discussed.     

3,6‐Di­chloro‐4‐[2‐(4‐thia­morpholino)­ethanesulfanyl]­pyridazine and 3,6‐bis­(pyrazol‐1‐yl)‐4‐[2‐(4‐thia­mor­pho­lino)­ethanesulfanyl]­pyridazine

The trans–trans conformations adopted by the derivatized bis­(bidentate) chelating N₄‐donor ligand 3,6‐bis­(pyrazol‐1‐yl)‐4‐[2‐(4‐thia­morpholino)­ethanesulfanyl]­pyridazine, C₁₆H₁₉N₇S₂, and an intermediate in its formation, 3,6‐di­chloro‐4‐[2‐(4‐thia­morpholino)­ethanesulfanyl]­pyridazine, C₁₀H₁₃Cl₂N₃S₂, con­trast with the cis–cis conformation found previously for 3,6‐bis­(thio­phen‐2‐yl)­pyridazine [Ackers, Blake, Hill & Hubberstey (2002). Acta Cryst. C 58 , o640–o641], which places all four heteroatoms on the same side of the mol­ecule.     

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.     

Bis­[1,3‐bis­(tri­methyl­silyl)­allyl]­cobalt(II), a stable electron‐deficient allyl complex

The title compound, bis­[(1,2,3‐η)‐(2E)‐1,3‐bis­(tri­methyl­silyl)­prop‐2‐enyl]­cobalt(II), [Co(C₉H₂₁Si₂)₂], is a homoleptic allyl complex with η³‐bound ligands. The Co—C distances range from 1.996 (3) to 2.096 (3) Å and the allyl ligands adopt staggered, nearly parallel, arrangements around the Co atom. The tri­methyl­silyl groups are in syn–anti conformations; the steric shielding they provide to the metal is probably responsible for the thermal stability of the compound.     

Di‐μ‐chloro‐bis­{bis­[2,5‐bis­(4‐methoxy­phenyl)‐1,3,4‐oxadiazole‐κ2C2′,N]iridium(III)] dichloro­methane disolvate

In the title compound, [Ir₂(C₁₆H₁₃N₂O₃)₄Cl₂]·2CH₂Cl₂, the two Ir atoms, 3.7075 (6) Å apart, are bridged by two Cl atoms which straddle a twofold axis of rotation through the two Ir atoms. Each Ir centre resides in a distorted octa­hedral environment completed by two chelating 2,5‐bis­(4‐methoxy­phenyl)‐1,3,4‐oxadiazole ligands, with trans‐N—N and cis‐C—C dispositions. In the stacking structure, there are two types of hydrogen bonds, involving the meth­oxy substitutent, an N atom of the oxadiazole ring and the dichloro­methane solvent mol­ecules.