In the title hydrated Schiff base, C13H12N4O3·H2O, the dihedral angle between the aromatic rings is 5.06 (11)° and an intra­molecular O—H⋯N hydrogen bond closes an S(6) ring. In the crystal, Ow—H⋯O and Ow—H⋯N (w = water) hydrogen bonds link the components into centrosymmetric tetra­mers (two Schiff bases and two water mol­ecules). Longer N—H⋯O hydrogen bonds link the tetra­mers into [010] chains. A weak C—H⋯O hydrogen bond and aromatic π–π stacking between the pyrazine and phenyl rings [centroid–centroid separations = 3.604 (2) and 3.715 (2) Å] are also observed.

In the title compound, C12H9ClN2O, the dihedral angle between the aromatic rings is 1.78 (4)° and an intra­molecular O—H⋯N hydrogen bond closes an S(6) ring. In the crystal, C—H⋯O and C—H⋯N hydrogen bonds connect the mol­ecules into [001] chains.

The title compound, [Co(C18H37N2)2(NCS)4], consists of a cobalt(II) ion positioned on the origin of the triclinic unit cell. It is coordinated by the N atoms of two trans-oriented 1-dodecyl-4-aza-1-azoniabi­cyclo­[2.2.2]octane (DABCO+) cations, which carry n-dodecyl chains at the non-coordinating N atoms. The distorted octa­hedral coordination environment of the CoII ion is completed through four N atoms of iso­thio­cyanate ions, which are arranged within the equatorial plane. Non-classical hydrogen bonding of the types C—H⋯N and C—H⋯S between the filamentous mol­ecules lead to the formation of layers parallel to (001).

In the title complex, [NiCl2(C12H9N3)2]·H2O, a divalent nickel atom is coordinated by two 2-(pyridin-2-yl)-1H-benzimidazole ligands in a slightly distorted octa­hedral environment defined by four N donors of two N,N'-chelating ligands, along with two cis-oriented anionic chloride donors. The title complex crystallized with a water mol­ecule disordered over two positions. In the crystal, a combination of O—H⋯Cl, O—H.·O and N—H⋯Cl hydrogen bonds, together with C—H⋯O, C—H⋯Cl and C—H⋯π inter­actions, links the complex mol­ecules and the water mol­ecules to form a supra­molecular three-dimensional framework. The title complex is isostructural with the cobalt(II) dichloride complex reported previously [Das et al. (2011). Org. Biomol. Chem. 9, 7097–7107].

In the title compound, C16H21N3O4, the 1,4-di­hydro­pyridine ring adopts a flattened boat conformation, with the imidazole substituent in an axial orientation [dihedral angle between ring planes = 82.9 (6)°]. In the crystal structure, pairs of N—H⋯O and N—H⋯N hydrogen bonds with graph-set notation R22(14) connect the mol­ecules into chains running along the c-axis direction.

The title compound, [Bi(C9H6NS2)3], was prepared by reacting BiCl3 and 2-mercapto-4-phenyl­thia­zole (LH) at room temperature in a stoichiometric ratio of 1:4. The mol­ecular structure reveals a slightly distorted square-pyramidal environment around the BiIII atom. Two of the three monoanionic ligands L− coordinate in an N,S-bidentate mode, while one shows a monodentate mode through an S atom. There are no significant inter­molecular inter­actions present in the crystal.

In the title mol­ecule, C18H17FO5, the conformation about the C=C bond of the central enone group is trans. The dihedral angle between the benzene rings is 13.08 (3)°. The hy­droxy group attached to the benzene ring is involved in an intra­molecular O—H⋯O hydrogen bond. In the crystal, weak C—H⋯O hydrogen bonds link the mol­ecules into chains along [001].

The title compound, C25H22N2O2Se, crystallizes in the space group P21/c with one mol­ecule in the asymmetric unit. The compound was synthesized by the addition of phenyl­selenyl bromide to a cyanamide. The phenyl­selenyl portion and the cyano group, as well as the ketone functional group in the cyclo­hexa-2,5-dien-1-one portion of the structure, are disordered, with occupancy factors of 0.555 (14) and 0.445 (14).

The structure of the title salt, C6H10N22+·2C7H7O3S−, consists of a unique benzene-1,2-diaminium dication charge balanced by a pair of crystallographically independent 4-methyl­benzene-1-sulfonate anions. The cations and anions are inter­linked by several N—H⋯O hydrogen bonds.

In the title compound, C19H13IO2, the dihedral angle between the naphthyl ring system and the pendant iodo­phenyl ring is 72.48 (11)°. In the crystal, C—H⋯π inter­actions and I⋯O [3.293 (2) Å] halogen bonds are observed, which combine to generate a herringbone packing motif.

The title compound, C20H18N4O2, known as bis­pyrazolone, was crystallized from dimethyl sulfoxide. The structure has ortho­rhom­bic (Pbca) symmetry at 150 K, and displays both intra- and inter­molecular hydrogen bonding through C—H⋯O and N—H⋯O contacts, respectively. None of the phenyl and pyrazolone rings in the mol­ecule are coplanar. The dihedral angle between the pyrazolone rings is 66.18 (5)°.

Caesium tetra­fluorido­bromate(III), CsBrF4, was crystallized in form of small blocks by melting and recrystallization. The crystal structure of CsBrF4 was redetermined from single-crystal X-ray diffraction data. In comparison with a previous study based on powder X-ray diffraction data [Ivlev et al. (2013). Z. Anorg. Allg. Chem. 639, 2846–2850], bond lengths and angles were determined with higher precision, and all atoms were refined with anisotropic displacement parameters. It was confirmed that the structure of CsBrF4 contains two square-planar [BrF4]− anions each with point group symmetry mmm, and a caesium cation (site symmetry mm2) that is coordinated by twelve fluorine atoms, forming an anti­cubocta­hedron. CsBrF4 is isotypic with CsAuF4.

The title hemihydrate, C12H9N5·0.5H2O, was isolated from the condensation reaction of quinoline-2-carbaldehyde with 4-amino-4H-1,2,4-triazole. The Schiff base mol­ecule adopts an E configuration about the C=N bond and is approximately planar, with a dihedral angle between the quinoline ring system and the 1,2,4-triazole ring of 12.2 (1)°. In the crystal, one water mol­ecule bridges two Schiff base mol­ecules via O—H⋯N hydrogen bonds. The Schiff base mol­ecules are inter­connected by π–π stacking inter­actions [centroid-centroid distances of 3.7486 (7) and 3.9003 (7) Å] into columns along [1overline{1}0].

In the title compound, C21H20BrNO4S, a key inter­mediate in the synthesis of the widely used β-lactamase inhibitor tazobactam, the five-membered thia­zolidine ring adopts an envelope conformation and the four-membered azetidine ring is in a distorted planar conformation. The crystal structure features C—H⋯O hydrogen bonds and a weak C—H⋯π inter­action.

The title carbonate hydrate, Cs2Mg4(CO3)5·10H2O, was crystallized at room temperature out of aqueous solutions containing caesium bicarbonate and magnesium nitrate. Its monoclinic crystal structure (P21/n) consists of double chains of composition 1∞[Mg(H2O)2/1(CO3)3/3], isolated [Mg(H2O)(CO3)2]2– units, two crystallographically distinct Cs+ ions and a free water mol­ecule. The crystal under investigation was twinned by reticular pseudomerohedry.

The structure of the title compound, H3O+·C2F6NO4S2−·C12H24O6 or [H3O+·C12H24O6][N(SO2CF3)2−], which is an ionic liquid with a melting point of 341–343 K, has been determined at 113 K. The asymmetric unit consists of two crystallographically independent 18-crown-6 mol­ecules, two hydro­nium ions and two bis­(tri­fluoro­methane­sulfon­yl)amide anions; each 18-crown-6 mol­ecule complexes with a hydro­nium ion. In one 18-crown-6 mol­ecule, a part of the ring exhibits conformational disorder over two sets of sites with an occupancy ratio of 0.533 (13):0.467 (13). One hydro­nium ion is complexed with the ordered 18-crown-6 mol­ecule via O—H⋯O hydrogen bonds with H2OH⋯OC distances of 1.90 (6)–2.19 (7) Å, and the other hydro­nium ion with the disordered crown mol­ecule with distances of 1.85 (6)–2.36 (6) Å. The hydro­nium ions are also linked to the anions via O—H⋯F hydrogen bonds. The crystal studied was found to be a racemic twin with a component ratio of 0.55 (13):0.45 (13).

The title compound, C21H39NS2, crystallizes with two mol­ecules in the asymmetric unit, both having a linear 18-carbon alkyl chain bound through a thio­ether group. No π–π stacking or hydrogen bonding is observed. The orientation of the alkyl chains facilitates inter­molecular inter­actions between te chains. The structure is metrically ortho­rhom­bic but crystallizes in the monoclinic space group P21 and was found to be twinned by pseudomerohedry (emulating ortho­rhom­bic symmetry) and by inversion. The twin factions refined to 0.37 (4), 0.13 (4), 0.31 (5), and 0.19 (4).

The title compound, C11H10N2O2S2, crystallizes with one complete mol­ecule in the asymmetric unit. In the crystal, weak hydrogen bonding is observed between the N-oxide moieties and several C—H units.

The title compound, C16H9N3O2S2, was synthesized via a condensation reaction in refluxing acetic acid. The dihedral angles between the mean plane of the quinoxaline unit and the thienyl rings are 35.16 (5)° and 24.94 (3)°.

The title compound, C16H9N3O2S2, was synthesized via a condensation reaction in refluxing acetic acid. One thienyl ring is nearly coplanar with the quinoxaline unit [dihedral angle = 3.29 (9)°], the other makes an angle of 83.96 (4)°.

The title naphthalene derivative, C24H20O2, features 4-methy­oxy-substituted benzene rings in the 1 and 4 positions of the naphthalene ring system. There are two crystallographically independent mol­ecules (A and B) in asymmetric unit. The independent mol­ecules have very similar conformations in which the naphthalene ring systems are only slightly bent, exhibiting dihedral angles between the constituent benzene rings of 3.76 (15) and 3.39 (15)° for A and B, respectively. The pendent 4-methyoxybenzene rings are splayed out of the plane through the naphthalene ring system to which they are connected [range of dihedral angles = 59.63 (13) to 67.09 (13)°]. In the crystal, the mol­ecular packing is consolidated by inter­molecular C—H⋯π inter­actions, leading to supra­molecular chains along the b axis. The chains assemble without directional inter­actions between them.

The tricyclic core in the title compound, C26H34O4Si2, shows disorder of the furan ring and deviates slightly from planarity, with the largest displacement from the least-squares plane [0.166 (2) Å] for the major disordered part of the methine C atom. To this C atom the likewise disordered vinyl group is attached, lying nearly perpendicular to the tricyclic core. In the crystal, mutual C—H⋯π inter­actions between the methine group of the furan ring and the central ring of the tricyclic core of an adjacent mol­ecule lead to inversion-related dimers.

In the extended structure of the title mol­ecular salt, C6H9N2+·C7H7O3S−, the cations and anions are linked by N—H⋯O hydrogen bonds to generate [010] chains.

In the title compound [systematic name: 5-methyl-1,3-bis­(2-oxoprop­yl)pyrimidine-2,4(1H,3H)-dione], C11H14N2O4, the two 2-oxopropyl groups are nearly perpendicular to the planar thymine unit. One methyl group of oxopropyl substituent is disordered. In the crystal, C—H⋯O inter­actions help to connect the mol­ecules into (001) layers.

The title compound, (C15H23N2)2[MnBr4], comprises two N-adamantyl-N'-ethyl­imidazolium cations and one tetra­hedral [MnBr4]2− anion. Next to Coulombic inter­actions, weak hydrogen bonds of the type C—H⋯Br consolidate the crystal packing, building up a three-dimensional network.

The relative stereo- and regiochemistry of the racemic title compound, C25H19NO7, were established from the crystal structure. The fused benzene ring forms dihedral angles of 77.3 (1) and 60.3 (1)° with the hy­droxy-substituted benzene ring and the nitro-substituted benzene ring, respectively. The dihedral angle between the hy­droxy-substituted benzene ring and the nitro-substituted benzene ring is 76.4 (1)°. An intra­molecular O—H⋯O hydrogen bond closes an S(6) ring. In the crystal, weak C—H⋯O hydrogen bonds connect the mol­ecules, forming layers parallel to (100). Within these layers, there are weak π–π stacking inter­actions with a ring centroid–ring centroid distance of 3.555 (1) Å.

The structure of the tertiary amine tris­(1H-benzimidazol-2-ylmeth­yl)amine (C24H21N7, abbreviated ntb) has been previously reported twice as solvates, namely the monohydrate and the aceto­nitrile–methanol–water (1/0.5/1.5) solvate, both with the tripodal conformation formed via multiple hydrogen bonds. Now, we report the tri­methanol adduct, ntb·3CH3OH, where the amine has the stair conformation featuring one benzimidazole group oriented in the opposite direction from the other two. The asymmetric unit contains one-half amine, completed through the mirror plane m in space group Pmn21 to form the ntb mol­ecule, with the H atom for each imidazole moiety equally disordered between both N sites available in the imidazole ring. The asymmetric unit also contains one and a half methanol mol­ecules, one being placed in general position with the hy­droxy H atom disordered over two sites with occupancy ratio 1:1, while the other lies on the m mirror plane, and has thus its hy­droxy H atom disordered by symmetry. As in the previously reported solvates, all imine and amine groups of the ntb mol­ecules and the methanol mol­ecules are involved in N—H⋯O and O—H⋯N hydrogen bonds. In the title compound, however, the involved H atom is systematically a disordered H atom provided by an imidazole group or a methanol mol­ecule.

In the title compound, C14H14O, the seven-membered ring is in a pseudo-chair conformation. In the crystal, mol­ecules are linked by weak C—H⋯O hydrogen bonds forming layers parallel to (010). In addition, there are weak π–π stacking inter­actions between inversion-related naphthalene ring systems, with a ring centroid–ring centroid distance of 3.518 (5) Å.

In the title compound, C19H16O, the pyran ring is in a half-chair conformation. The essentially planar naphthalene ring system (r.m.s. deviation = 0.020 Å) forms a dihedral angle of 14.37 (5)° with the fused benzene ring. In the crystal, pairs of mol­ecules are connected into inversion dimers by weak C—H⋯O hydrogen bonds to generate R22(6) loops.

Irradiation of 1-(1-benzo­cyclo­butenyl­idene)benzo­cyclo­butene gives indeno­indene and its head-to-head photodimer nona­cyclo­[9.7.7.72,10.01,11.02,10.03,8.012,17.019,24.026,31]dotriaconta-3,5,7,12,14,16,19,21,23,26,28,30-dodeca­ene, C32H24. The mol­ecule is built from four essentially planar indane units attached to an elongated cyclo­butane ring. In the crystal, C—H⋯π inter­actions connect mol­ecules into layers parallel to the bc plane.

The title salt, (PMIM)2[Ni(P2S8)2] (PMIM = 3-methyl-1-propyl-1H-imidazol-3-ium, C7H13N2+), consists of a nickel–thio­phosphate anion charge-balanced by a pair of crystallographically independent PMIM cations. It crystallizes in the monoclinic space group P21/n. The structure exhibits the known [Ni(P2S8)2]2− anion with two unique imidazolium cations in the asymmetric unit. Whereas one PMIM cation is well ordered, the other is disordered over two orientations with refined occupancies of 0.798 (2) and 0.202 (2). The salt was prepared directly from the elements in the ionic liquid [PMIM]CF3SO3. Whereas one of the PMIM cations is well behaved (it does not exhibit disorder even in the propyl side chain), the other is found in two overlapping positions. The refined occupancies for the two orientations are roughly 80:20. Here, too, there appears to be little disorder in the propyl arm.

Crystals of the dimethyl sulfoxide (DMSO) solvate of [1–9-NαC]-linusorb B3 (Cyclo­linopeptide A; CLP-A; C57H84N9O9·C2H6OS), a cyclic polypeptide were obtained following peptide extraction and purification from flaxseed oil. There are four intramolecular N—H⋯O hydrogen bonds. In the crystal, the mol­ecules are linked in chains along the a axis by N—H⋯O hydrogen bonds. Each DMSO O atom accepts a hydrogen bond from an NH group at the Phe6 location in the CLP-A mol­ecule.

In the title compound, C19H18O2, the pyran ring is in a half-chair conformation. The fused ring system comprising the benzene and cyclo­hexene rings is essentially planar (r.m.s. deviation = 0.053 Å) and forms a dihedral angle of 27.95 (6)° with the other benzene ring. In the crystal, O—H⋯O hydrogen bonds connect the mol­ecules into chains propagating along [001].

A quinazolinthione, C17H14N2OS, was synthesized by the condensation reaction of 6,7,8,9-tetra­hydro-11H-pyrido[2,1-b]quinazolin-11-thione with furfural. The mol­ecule crystallizes in the monoclinic system (Cc space group) and has an E configuration with respect to the exocyclic C=C bond. In the crystal, mol­ecules are linked through C—H⋯π(furan) inter­actions, forming zigzag chains propagating along the [001] direction.

The mol­ecule of the title compound, C30H22N4, exhibits inversion symmetry adopting the shape of a St Andrew's Cross. It shows dihedral angles between adjacent aryl units of around 50° whereas torsion angles of ca 10° are found along the aryl­ene vinyl­ene path.

In the title compound, C14H11ClN2O2S, the dihedral angle between the pyrrolo­[1,2-c]pyrimidine ring system (r.m.s. deviation = 0.008 Å) and the benzene ring is 80.2 (9)°. In the crystal, inversion dimers linked by pairs of C—H⋯O inter­actions generate R22(16) loops. Several aromatic π–π stacking inter­actions between the pyrrolo­[1,2-c]pyrimidine rings, as well as separately between the pyrrolo and pyrimidine groups [shortest centroid–centroid separation = 3.5758 (14) Å], help to consolidate the packing.

In the title compound, C10H13N5, the piperidine ring adopts a chair conformation with the exocyclic N—C bond in an axial orientation, and the dihedral angle between the mean planes of piperidine and pyrimidine rings is 49.57 (11)°. A short intra­molecular C—H⋯N contact generates an S(7) ring. In the crystal, N—H⋯N hydrogen bonds link the mol­ecules into (100) sheets and a weak aromatic π-π stacking inter­action is observed [centroid–centroid separation = 3.5559 (11) Å] between inversion-related pyrimidine rings.

The reaction of ligand 5,7-di­hydro-1H,3H-dithieno[3,4-b:3',4'-e]pyrazine (L) with CuI lead to the formation of a three-dimensional coordination polymer, incorporating the well known [CuxIx]n staircase motif (x = 4). These polymer [Cu4I4]n chains are linked via the N and S atoms of the ligand to form the three-dimensional coordination polymer poly[(μ4-5,7-di­hydro-1H,3H-dithieno[3,4-b:3',4'-e]pyrazine-κ4N:N':S:S')tetra-μ3-iodido-tetra­copper], [Cu4I4(C8H8N2S2)]n (I). The asymmetric unit is composed of half a ligand mol­ecule, with the pyrazine ring located about a center of symmetry, and two independent copper(I) atoms and two independent I− ions forming the staircase motif via centers of inversion symmetry. The framework is consolidated by C—H⋯I hydrogen bonds.

The title compound, C26H22O6, is formed as the major product from the reaction between syn-1,2-bis­(pinacolatoboron)-1,2-bis­(4-methyl­carb­oxy­phen­yl)ethene and excess methyl 4-iodo­benzoate in basic DMSO using a palladium catalyst at 80°C via Suzuki coupling followed by protodeboronation. Crystals were grown by slow evaporation of a hexa­nes solution at room temperature.

An aluminium-deficient Al8Cr5-type inter­metallic with formula Al7.85Cr5.16 (octa­aluminium penta­chromium) was uncovered when high-pressure sinter­ing of a mixture with composition Al11Cr4 was carried out. Structure analysis reveals that there are three co-occupied positions with refined occupancy factors for Al atoms being 0.958, 0.772 and 1/2. The present phase is confirmed to be isotypic with the previously reported rhombohedral Al8Cr5 ordered phase [Bradley & Lu (1937). Z. Kristallogr. 96, 20–37] and structurally closely related to the disordered phases of rhombohedral Al16Cr9.5 and cubic Al8Cr5.

In the title compound, C16H19N3O2Si, the dihedral angle between the coumarin ring system (r.m.s. deviation = 0.031 Å) and the triazole ring is 73.81 (8)°. In the crystal, mol­ecules are linked into [010] chains by weak C—H⋯O inter­actions.

The asymmetric unit of the binuclear title compound, [Cu2(C8H7O3)4(H2O)2], comprises two halves of diaquatetra­kis­(μ-3-meth­oxy­benzoato-κ2O1:O1')dicopper(II) units. The paddle-wheel structure of each complex is completed by application of inversion symmetry, with the inversion centre situated at the midpoint between two CuII atoms in each dimer. The two CuII atoms of each centrosymmetric dimer are bridged by four 3-meth­oxy­benzoate anions resulting in Cu⋯Cu separations of 2.5961 (11) and 2.6060 (12) Å, respectively. The square-pyramidal coordination sphere of each CuII atom is completed by an apical water mol­ecule. Inter­molecular O—H⋯O hydrogen bonds of weak nature link the complexes into layers parallel to (100). The three-dimensional network structure is accomplished by C—H⋯O hydrogen bonds inter­linking adjacent layers.

In the crystal of the title compound, C6H6F8O4, O—H⋯O hydrogen bonds involving the hy­droxy groups connect the mol­ecules, forming a two-dimensional network parallel to (100). These hydrogen-bonding inter­actions appear to drive the O—C—C—O torsion angles into a gauche–trans–trans series of conformations along the backbone of the mol­ecule.

The title hepta­nuclear alkoxido(oxido)vanadium(V) oxide cluster complex, [V7(C10H19O)O17(C18H24N2)3]·CH3CN, was obtained by the reaction of [V8O20(C18H24N2)4] with 4-tert-butyl­cyclo­hexa­nol (mixture of cis and trans) in a mixed CHCl3/CH3CN solvent. The complex has a V7O18N6 core with approximately Cs symmetry, which is composed of two VO4 tetra­hedra, two VO6 octa­hedra and three VO4N2 octa­hedra. In the crystal, these complexes are linked together by weak inter­molecular C—H⋯O hydrogen bonds between the 4,4'-di-tert-butyl-2,2'-bi­pyridine ligand and the V7O18N6 core, forming a one-dimensional network along the c-axis direction. Besides the complex, the asymmetric unit contains one CH3CN solvent mol­ecule. The contribution of other disordered solvent mol­ecules to the scattering was removed using the SQUEEZE option in PLATON [Spek (2015). Acta Cryst. C71, 9–18]. The unknown solvent mol­ecules are not considered in the chemical formula and other crystal data.

The title compound, C16H16N2, was synthesized by dispersing 3,4-hexa­nedione in a methanol–water solution containing the acid catalyst NH4HF2, then adding 1,2-di­aminona­phthalene. The fused-ring system of the title compound is close to planar (r.m.s. deviation = 0.028 Å); one of the pendant methyl C atoms lies close to the ring plane [deviation = 0.071 (2) Å; N—C—C—C = −0.27 (18)°] whereas the other is significantly displaced [–1.7136 (18) Å; 91.64 (16)°]. The mol­ecules pack in space group Ioverline{4} in a distinctive criss-cross motif supported by numerous aromatic π–π stacking inter­actions [shortest centroid–centroid separation = 3.5805 (6) Å].

The reaction of ligand 3,4,8,10,11,13-hexa­hydro-1H,6H-bis­([1,4]di­thio­cino)[6,7-b:6',7'-e]pyrazine (L) with CuI led to the formation of a two-dimensional coordination polymer, incorporating a [Cu2I2] motif. These units are linked via the four S atoms of the ligand to form the title two-dimensional coordination poly­mer, poly[[μ4-3,4,8,10,11,13-hexa­hydro-1H,6H-bis­([1,4]di­thio­cino)[6,7-b:6',7'-e]pyrazine]di-μ-iodido-dicopper(I)], [Cu2I2(C12H16N2S4)]n, (I). The asymmetric unit is composed of a ligand mol­ecule, two copper(I) atoms and two I− ions. Both copper(I) atoms are fourfold S2I2 coordinate with almost regular trigonal-pyramidal environments. In the crystal, the layers, lying parallel to (102), are linked by C—H⋯I hydrogen bonds, forming a supra­molecular framework.

The crystal structure of (NH4)2V3O8 has been reported twice using single-crystal X-ray data [Theobald et al. (1984). J. Phys. Chem. Solids, 45, 581–587; Range et al. (1988). Z. Naturforsch. Teil B, 43, 309–317]. In both cases, the orientation of the ammonium cation in the asymmetric unit was poorly defined: in Theobald's study, the shape and dimensions were constrained for NH4+, while in Range's study, H atoms were not included. In the present study, we collected a highly redundant data set for this ternary oxide, at 0.61 Å resolution, using Ag Kα radiation. These accurate data reveal that the NH4+ cation is disordered by rotation around a non-crystallographic axis. The rotation axis coincides with one N—H bond lying in the mirror m symmetry element of space-group type P4bm, and the remaining H sites were modelled over two disordered positions, with equal occupancy. It therefore follows that the NH4+ cations filling the space available in the (001) layered structure formed by (V3O8)2– ions do not form strong N—H⋯O hydrogen bonds with the mixed-valent oxidovanadate(IV,V) anions. This feature could have consequences for the Li-ion inter­calation properties of this material, which is used as a cathode for supercapacitors.

The title compound {systematic name: N-[2-(5-meth­oxy-1H-indol-3-yl)eth­yl]-N-(prop-2-en-1-yl)prop-2-en-1-amine), C17H22N2O, has a single tryptamine mol­ecule in the asymmetric unit. The mol­ecules are linked by strong N—H⋯N hydrogen bonds into zigzag chains with graph-set notation C(7) along the [010] direction.

In the title compound, C20H21NO, the dihedral angle between the phenyl ring is 47.5 (1)° and the piperidine ring adopts a chair conformation. In the crystal, mol­ecules are linked by C—H⋯π inter­actions into dimers with the mol­ecules related by twofold symmetry.

The title compound, C52H40N2, is disposed about a centre of inversion and the conformation about the imine bond [1.268 (3) Å] is E. The terminal benzene ring is approximately perpendicular to the central 1,4-di­aza­butadiene mean plane, forming a dihedral angle of 81.2 (3)°. Weak C—H⋯π and π–π [inter-centroid distance = 4.021 (5) Å] inter­actions help to consolidate the packing.