4,6‐Di­chloro‐2‐(methyl­thio)­pyrimidine

The structure of the title compound, C₃₀H₂₄Cl₁₂N₁₂S₆, (I), comprises six symmetry unique mol­ecules that vary only slightly in their N—C—S—C torsion angle. All the mol­ecules are planar to within less than 3.1°.     

2‐[Benzoyl­(hydroxy­imino)­methyl­amino]­benzoic acid

The structure of the title compound, C₁₅H₁₂N₂O₄, consists of a polymeric arrangement, around inversion centres, of mol­ecules linked through O—H⋯N and O—H⋯O hydrogen bonds; there are also intramolecular hydrogen bonds. All these hydrogen‐bond interactions result in the formation of infinite chains parallel to the [010] direction. The oxime group has an E conformation.     

Di­methyl(2‐methyl­phenyl)­ammonium hydroxo­tris­(penta­fluoro­phenyl)­borate

In the title compound, [(CH₃)₂(C₇H₇)NH][(C₆F₅)₃B(OH)] or C₉H₁₄N⁺·C₁₈HBF₁₅O^?, the distorted tetrahedral borate anions are strongly hydrogen bonded to the substituted ammonium cations. The N?O separation in the N—H?O hydrogen bond is 2.728 (3) Å.     

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.     

2‐(2‐Oxoimidazolidinyl)ethyl 2‐methyl­prop‐2‐enoate

In the crystal structure of the title compound, C₉H₁₄N₂O₃, the molecules are linked by N—H?O=C bonds into chains parallel to [001]. Large crystals are readily obtained, presumably because of the hydrogen bonds and an energetically stable conformation of the mol­ecule.     

4‐[4‐(Di­methyl­amino)­benzyl­idene­amino]‐3,5‐bis(2‐pyridyl)‐4H‐1,2,4‐triazole

The title compound, C₂₁H₁₉N₇, is a poly­pyridine ligand that is suitable for assembling complex metal systems capable of photoinduced electron transfer. The solid‐state structure has been determined at room temperature by single‐crystal X‐ray diffraction. The mol­ecule is not flat and both the bis­(pyridyl)­triazole and the benzyl­id­ene­amine fragments show significant distortions from planarity.     

1,4‐Di­methyl­pyridinium hexakis­(di­methyl­form­amide‐κO)­calcium(II) dodecamolybdophosphate

In the title compound, (C₇H₁₀N)[Ca(C₃H₇NO)₆][PMo₁₂O₄₀], two types of cations {viz. 1,4‐di­methyl­pyridinium and a [Ca(DMF)₆]²⁺ complex cation (DMF is di­methyl­form­amide)} and dodecamolybdophosphate (tetra­conta­oxo­phos­phido­dodeca­molybdate) anions form an infinite three‐dimensional assembly via electrostatic forces.     

trans‐Di­chlorotetrakis(4‐methyl­pyridine)­silicon bis­(triiodide) chloro­form solvate

At 173 K, the dication of the title compound, C₂₄H₂₈Cl₂N₄Si²⁺·2I₃^?·CHCl₃, is located on a crystallographic fourfold rotation axis. The chloro ligands occupy axial positions and the four 4‐methyl­pyridine ligands lie in the equatorial plane. The almost linear I₃^? ion is located on a crystallographic mirror plane and displays two significantly different I—I bond lengths. Furthermore, chloro­form mol­ecules, which are disordered about a centre of inversion, fill the remaining gaps in the crystal structure.     

1‐(2‐Hydroxy‐4,6‐di­methyl­phenyl)­ethanone

In the crystal of the title compound, C₁₀H₁₂O₂, there are two symmetry‐independent mol­ecules, which are essentially superimposable. Each mol­ecule exhibits an intramolecular O—H?O hydrogen bond, with O?O separations of 2.483 (4) and 2.468 (4) Å.     

(E,E,E)‐1,3,5‐Tris[4‐(acetyl­sulfan­yl)­styr­yl]­benzene toluene hemisolvate

The first crystal structure of a three‐terminal sulfur end‐capped oligo­phenyl­ene­vinyl­ene, C₃₆H₃₀O₃S₃·0.5C₇H₈, has been determined at 122 (1) K. The mol­ecular threefold symmetry is not utilized in the crystal structure. It is confirmed that the double bonds have been fully transformed into a trans configuration by iodine treatment.     

3‐Acetoxy‐2‐(acetyl­amino)pyridinium‐1‐squarate

The title compound, alternatively known as 3‐acetoxy‐2‐(acetylamino)pyridinium betaine of squaric acid, C₁₃H₁₀N₂O₆, has been synthesized. The bond distances within the squarate ring indicate two possible resonance structures. The mean planes of the pyridinium and squarate systems are inclined at an angle of 24.0 (2)° with respect to one another due to a strong intramolecular hydrogen‐bonding interaction between the amide NH group and a squarate O atom. In the extended structure, there are additional weak π–π and π–ring interactions, which also stabilize the crystal structure.     

Bis­[4‐(2‐pyridyl­methyl­ene­amino)­phenyl] ether

The title compound, C₂₄H₁₈N₄O, is a bis‐bidentate Schiff base ligand exhibiting pseudo‐C₂ symmetry. The mol­ecule is twisted about the central ether linkage and exhibits an imine E configuration. In the crystal, the mol­ecules are linked by weak intermolecular C—H?N hydrogen bonds.     

3,5‐Di­methyl‐4‐(2,4,6‐tri­methyl­phenyl­diazenyl)­phenol

In the title compound, C₁₇H₂₀N₂O, (I), the dihedral angle between the two phenyl rings is 15.69 (6)°. An intermolecular hydrogen‐bonding association exists between the hydroxy group and one of the azo N atoms.     

1‐[(4‐Chloro­benzoyl)­methyl]‐4‐(N,N‐di­methyl­amino)­pyridinium bromide sesquihydrate and 1‐[(4‐bromo­benzoyl)­methyl]‐4‐(N,N‐di­methyl­amino)­pyridinium bromide sesquihydrate

The title compounds, C₁₅H₁₆ClN₂O⁺·Br⁻·1.5H₂O and C₁₅H₁₆BrN₂O⁺·Br⁻·1.5H₂O, are isomorphous. The benzene ring is oriented nearly normal to the pyridine ring in both compounds. The molecular packing is mainly influenced by intermolecular O—H⋯O and O—H⋯Br interactions, as well as weak intramolecular C—H⋯O interactions. The H₂OBr⁻ units form an extended water–bromide chain, with a bridging water mol­ecule on a twofold axis.     

Di­methyl 2‐{[2‐(methoxy­carbonyl)‐1‐(methoxy­carbonyl­methyl)pyrrol‐4‐yl]­methyl­ene}propane­dioate

The title compound, C₁₅H₁₇NO₈, is a pyrrole–ethene derivative with potential biological activity. Although a large part of the mol­ecule is planar, there is no structural evidence for any conjugation push–pull effect across the ethyl­enic bond, which is usually observed for substituted ethyl­enes; π‐electron delocalization appears to be restricted to the 2‐(methoxy­carbonyl)­pyrrole moiety.     

The E and Z isomers of 3‐(benzoxazol‐2‐yl)­prop‐2‐enoic acid

The carboxyl­ic acid group and the double bond are coplanar in (E)‐3‐(benzoxazol‐2‐yl)­prop‐2‐enoic acid, C₁₀H₇NO₃, whereas in isomeric (Z)‐3‐(benzoxazol‐2‐yl)­prop‐2‐enoic acid, also C₁₀H₇NO₃, they are almost orthogonal. In both isomers, a strong O—H⋯N hydrogen bond, with the carboxyl­ic acid group as a donor and the pyridine‐like N atom as an acceptor, and weak C—H⋯O interactions contribute to the observed supramolecular structures, which are completed by π–π stacking interactions between oxazole and benzenoid rings.     

9‐(Tri­chloro­acetyl­imino)­acridine monohydrate

The title compound, alternatively called N‐acridin‐9(10H)‐yl­idene‐2,2,2‐tri­chloro­acet­amide mono­hydrate, C₁₅H₉Cl₃N₂O·H₂O, crystallizes in space group P2₁/c with Z = 4. The acridine moieties are arranged in layers, tilted at an angle of 15.20 (4)° relative to the ac plane, while adjacent mol­ecules pack in a head‐to‐tail manner. Acridine and water mol­ecules form columns along the b axis held in place by a network of hydrogen bonds, which is the major factor stabilizing the lattice. The acridine mol­ecule exhibits structural features of both the amino and imino forms, which could be due to the presence of the strong electronegative tri­chloro­acetyl substituent at the exocyclic N atom.     

(E,E)‐2,5‐Di­methoxy‐1,4‐bis­[2‐(3,4,5‐tri­methoxy­phenyl)­ethenyl]­benzene

In the title compound, C₃₀H₃₄O₈, molecular symmetry is coincident with crystallographic inversion symmetry. A three‐dimensional network is generated containing both C—H·π and C—H·n(O) interactions. A comparison of the geometry of this mol­ecule and the structure of a number of 2,4,6‐tri­methoxy‐substituted analogues is provided.     

Aqua­tris­(1,10‐phenan­throline)­(trans‐2,3‐di­methyl­acrylato)­ytterbium(III)

The title mononuclear complex, [Yb(C₅H₇O₂)₃(C₁₂H₈N₂)(H₂O)], is a most uncommon carboxylate complex of a rare earth metal. Each Yb^III ion is eightfold coordinated, being bonded to five O atoms of three dimethylacrylate groups, both N atoms of a phenanthroline and one O atom of a water molecule, giving a distorted square antiprismatic coordination polyhedron.