Di-μ-hydroxido-bis­[di­bromido­(di­methyl­formamide-κO)ethyl­tin(IV)], [Sn2Br4(C2H5)2(OH)2(C3H7NO)2], was prepared from ethyl­tin(IV) bromide and N,N-di­methyl­formamide (DMF) in air. The crystal structure exhibits the typical structural features of dimeric Lewis-base-stabilized monoorganotin(IV)–dihalide–hydroxides, RSnHal2(OH), i.e. two octa­hedrally coordinated Sn atoms are linked together via two bridging hydroxide groups, resulting in a centrosymmetric four-membered rhomboid-like Sn–OH ring with acute angles at the Sn atom, obtuse angles at the O atoms and two different tin–oxygen bond lengths. With the shorter bond trans to the ethyl group, this observation underlines once more the so-called trans-strengthening effect in monoorganotin(IV) com­pounds with octa­hedrally coordinated Sn atoms. Differences and similarities in the bond lengths and angles in the four-membered Sn–OH rings have been worked out for the rings in dimeric diorganotin(IV)–halide–hydroxides, [R2SnHal(OH)]2, and hydrates of dimeric tin(IV)–trihalide–hydroxide–aqua–hydrates, [SnHal3(OH)(H2O)]2·nH2O.

The title compound, [Co(C3H4N2)(C30H30N10)](BF4)2, is a five-coordinate CoII complex based on the neutral ligands tris­[(1-benzyl­triazol-4-yl)meth­yl]amine (tbta) and imidazole. It exhibits a distorted trigonal bipyramidal geometry in which the equatorial positions are occupied by the three N-atom donors from the triazole rings of the tripodal tbta ligand. The apical amine N-atom donor of tbta and the N-atom donor of the imidazole ligand occupy the axial positions of the coordination sphere. Two tetra­fluoro­borate anions provide charge balance in the crystal.

Two 2,4,6-tri­methyl­aniline-based trifuloro­methane­sulfonate (tri­fluoro­methane­sulfonate) salts were synthesized and characterized by single-crystal X-ray diffraction. N,2,4,6-Tetra­methyl­anilinium tri­fluoro­methane­sulfonate, [C10H14NH2+][CF3O3S−] (1), was synthesized via methyl­ation of 2,4,6-tri­methyl­aniline. N-Iso­propyl­idene-N,2,4,6-tetra­methyl­anilinium tri­fluoro­meth­ane­sulfonate, [C13H20N+][CF3O3S−] (2), was synthesized in a two-step reaction where the imine, N-iso­propyl­idene-2,4,6-tri­methyl­aniline, was first prepared via a dehydration reaction to form the Schiff base, followed by methyl­ation using methyl tri­fluoro­methane­sulfonate to form the iminium ion. In compound 1, both hydrogen bonding and π–π inter­actions form the main inter­molecular inter­actions. The primary inter­action is a strong N—H⋯O hydrogen bond with the oxygen atoms of the tri­fluoro­methane­sulfonate anions bonded to the hydrogen atoms of the ammonium nitro­gen atom to generate a one-dimensional chain. The [C10H14NH2+] cations form dimers where the benzene rings form a π–π inter­action with a parallel-displaced geometry. The separation distance between the calculated centroids of the benzene rings is 3.9129 (8) Å, and the inter­planar spacing and ring slippage between the dimers are 3.5156 (5) and 1.718 Å, respectively. For 2, the [C13H20N+] cations also form dimers as in 1, but with the benzene rings highly slipped. The distance between the calculated centroids of the benzene rings is 4.8937 (8) Å, and inter­planar spacing and ring slippage are 3.3646 (5) and 3.553 Å, respectively. The major inter­molecular inter­actions in 2 are instead a series of weaker C—H⋯O hydrogen bonds [C⋯O distances of 3.1723 (17), 3.3789 (18), and 3.3789 (18) Å], an inter­action virtually absent in the structure of 1. Fluorine atoms are not involved in strong directional inter­actions in either structure.

The complex [Pt(C9H6NO)Cl(C2H4)], (I), was synthesized and structurally characterized by ESI mass spectrometry, IR, NMR spectroscopy, DFT calculations and X-ray diffraction. The results showed that the deprotonated 8-hy­droxy­quinoline (C9H6NO) coordinates with the PtII atom via the N and O atoms while the ethyl­ene coordinates in the η2 manner and in the trans position compared to the coordinating N atom. The crystal packing is characterized by C—H⋯O, C—H⋯π, Cl⋯π and Pt⋯π inter­actions. Complex (I) showed high selective activity against Lu-1 and Hep-G2 cell lines with IC50 values of 0.8 and 0.4 µM, respectively, 54 and 33-fold more active than cisplatin. In particular, complex (I) is about 10 times less toxic to normal cells (HEK-293) than cancer cells Lu-1 and Hep-G2. Furthermore, the reaction of complex (I) with guanine at the N7 position was proposed and investigated using the DFT method. The results indicated that replacement of the ethyl­ene ligand with guanine is thermodynamically more favorable than the Cl ligand and that the reaction occurs via two consecutive steps, namely the replacement of ethyl­ene with H2O and the water with the guanine mol­ecule.

The title compound, C12H10N2O3, was obtained by the de­acetyl­ation reaction of 1-(6-amino-5-nitro­naphthalen-2-yl)ethanone in a concentrated sulfuric acid methanol solution. The mol­ecule comprises a naphthalene ring system bearing an acetyl group (C-3), an amino group (C-7), and a nitro group (C-8). In the crystal, the mol­ecules are assembled into a two-dimensional network by N⋯H/H⋯N and O⋯H/H⋯O hydrogen-bonding inter­actions. n–π and π–π stacking inter­actions are the dominant inter­actions in the three-dimensional crystal packing. Hirshfeld surface analysis indicates that the most important contributions are from O⋯H/H⋯O (34.9%), H⋯H (33.7%), and C⋯H/H⋯C (11.0%) contacts. The energies of the frontier mol­ecular orbitals were computed using density functional theory (DFT) calculations at the B3LYP-D3BJ/def2-TZVP level of theory and the LUMO–HOMO energy gap of the mol­ecule is 3.765 eV.

The new palladium(II) complex, [Pd(C16H16N4O3)2](CF3COO)2·2CF3COOH, crystallizes in the triclinic space group Poverline{1} with the asymmetric unit containing half the cation (PdII site symmetry Ci), one tri­fluoro­actetate anion and one co-crystallized tri­fluoro­acetic acid mol­ecule. Two neutral chelating 2-[5-(3,4,5-tri­meth­oxy­phen­yl)-4H-1,2,4-triazol-3-yl]pyridine ligands coordinate to the PdII ion through the triazole-N and pyridine-N atoms in a distorted trans-PdN4 square-planar configuration [Pd—N 1.991 (2), 2.037 (2) Å; cis N—Pd—N 79.65 (8), 100.35 (8)°]. The complex cation is quite planar, except for the methoxo groups (δ = 0.117 Å for one of the C atoms). The planar configuration is supported by two intra­molecular C—H⋯N hydrogen bonds. In the crystal, the π–π-stacked cations are arranged in sheets parallel to the ab plane that are flanked on both sides by the tri­fluoro­acetic acid–tri­fluoro­acetate anion pairs. Apart from classical N/O—H⋯O hydrogen-bonding inter­actions, weak C—H⋯F/N/O contacts consolidate the three-dimensional architecture. Both tri­fluoro­acetic moieties were found to be disordered over two resolvable positions with a refined occupancy ratio of 0.587 (1):0.413 (17) and 0.530 (6):0.470 (6) for the protonated and deprotonated forms, respectively.

The few examples of structures containing the 2-chloro-N,N-di­methyl­ethan-1-aminium or 3-chloro-N,N-di­methyl­propan-1-aminium cations show a compet­ition between gauche and anti conformations for the chloro­alkyl chain. To explore further the conformational landscape of these cations, and their possible use as mol­ecular switches, the title salts, (C4H11ClN)2[CoCl4] and (C4H11ClN)2[ZnCl4], were prepared and structurally characterized. Details of both structures are in close agreement. The inorganic complex exhibits a slightly flattened tetra­hedral geometry that likely arises from bifurcated N—H hydrogen bonds from the organic cations. The alkyl chain of the cation is disordered between gauche and anti conformations with the gauche conformation occupancy refined to 0.707 (2) for the cobaltate. The gauche conformation places the terminal Cl atom at a tetra­hedral face of the inorganic complex with a contact distance of 3.7576 (9) Å to the Co2+ center. The anti conformation places the terminal Cl atom at a contact distance to a neighboring anti conformation terminal Cl atom that is ∼1 Å less than the sum of the van der Waals radii. Thus, if the anti conformation is present at a site, then the nearest neighbor must be gauche. DFT geometry optimizations indicate the gauche conformation is more stable in vacuo by 0.226 eV, which reduces to 0.0584 eV when calculated in a uniform dielectric. DFT geometry optimizations for the unprotonated mol­ecule indicate the anti conformation is stabilized by 0.0428 eV in vacuo, with no strongly preferred conformation in uniform dielectric, to provide support to the notion that this cation could function as a mol­ecular switch via deprotonation.

The benzimidazole entity of the title mol­ecule, C17H21N5O, is almost planar (r.m.s. deviation = 0.0262 Å). In the crystal, bifurcated C—H⋯O hydrogen bonds link individual mol­ecules into layers extending parallel to the ac plane. Two weak C—H⋯π(ring) inter­actions may also be effective in the stabilization of the crystal structure. Hirshfeld surface analysis of the crystal structure reveals that the most important contributions for the crystal packing are from H⋯H (57.9%), H⋯C/C⋯H (18.1%) and H⋯O/O⋯H (14.9%) inter­actions. Hydrogen bonding and van der Waals inter­actions are the most dominant forces in the crystal packing. Evaluation of the electrostatic, dispersion and total energy frameworks indicate that the stabilization of the title compound is dominated via dispersion energy contributions. The mol­ecular structure optimized by density functional theory (DFT) at the B3LYP/6–311 G(d,p) level is compared with the experimentally determined mol­ecular structure in the solid state.

In the title compound, C6H4BrF3N4O2, the oxa­diazole ring is essentially planar with a maximum deviation of 0.003 (2) Å. In the crystal, mol­ecular pairs are connected by N—H⋯N hydrogen bonds, forming dimers with an R22(8) motif. The dimers are linked into layers parallel to the (10overline{4}) plane by N—H⋯O hydrogen bonds. In addition, C—O⋯π and C—Br⋯π inter­actions connect the mol­ecules, forming a three-dimensional network. The F atoms of the tri­fluoro­methyl group are disordered over two sites in a 0.515 (6): 0.485 (6) ratio. The inter­molecular inter­actions in the crystal structure were investigated and qu­anti­fied using Hirshfeld surface analysis.

The title compound, C12H16N2O, is a hy­droxy-substituted mono­amine alkaloid, and the primary metabolite of the naturally occurring psychedelic compound psilocybin. Crystalline forms of psilocin are known, but their characterization by single-crystal structure analysis is limited. Herein, two anhydrous polymorphic forms (I and II) of psilocin are described. The crystal structure of polymorphic Form I, in space group P21/c, was first reported in 1974. Along with the redeterm­ination to modern standards and unambiguous location of the acidic H atom and variable-temperature single-crystal unit-cell determinations for Form I, the Form II polymorph of the title compound, which crystallizes in the monoclinic space group P21/n, is described for the first time. The psilocin mol­ecules are present in both forms in their phenol–amine tautomeric forms (not resolved in the 1974 report). The mol­ecules in Forms I and II, however, feature different conformations of their N,N-dimethyl ethyl­ene substituent, with the N—C—C—C link in Form I being trans and in Form II being gauche, allowing the latter to bend back to the hydroxyl group of the same mol­ecule, leading to the formation of a strong intra­molecular O—H⋯N hydrogen bond between the hydroxyl moiety and ethyl­amino-nitro­gen group. In the extended structure of Form II, the mol­ecules form one-dimensional strands through N—H⋯O hydrogen bonds from the indole group to the oxygen atom of the hydroxyl moiety of an adjacent mol­ecule. Form II exhibits whole-mol­ecule disorder due to a pseudo-mirror operation, with an occupancy ratio of 0.689 (5):0.311 (5) for the two components. In contrast, Form I does not feature intra­molecular hydrogen bonds but forms a layered structure through inter­molecular N—H⋯O and O—H⋯N hydrogen bonds.

4,4'-(Disulfanedi­yl)dipyridinium chloride triiodide, C10H10N2S22+·Cl−·I3−, (1) was synthesized by reaction of 4,4'-di­pyridyl­disulfide with ICl in a 1:1 molar ratio in di­chloro­methane solution. The structural characterization of 1 by SC-XRD analysis was supported by elemental analysis, FT–IR, and FT–Raman spectroscopic measurements.

The title coordination polymer with the 4-methyl-N-(pyridin-2-yl­methyl­idene)aniline Schiff base ligand (L, C13H12N2), [Cd2Cl4(C13H12N2)]n (1), exhibits a columnar structure extending parallel to [100]. The columns are aligned in parallel and are decorated with chelating L ligands on both sides. They are elongated into a supra­molecular sheet extending parallel to (01overline{1}) through π–π stacking inter­actions involving L ligands of neighbouring columns. Adjacent sheets are packed into the tri-periodic supra­molecular network through weak C—H⋯Cl hydrogen-bonding inter­actions that involve the phenyl CH groups and chlorido ligands. The thermal stability and photoluminescent properties of (1) have also been examined.

The reaction of copper(II) oxalate and hexa­methyl­ene­tetra­mine in a deep eutectic solvent made of urea and choline chloride produced crystals of penta­amine­copper(II) dichloride–urea (1/1), [Cu(NH3)5]Cl2·CO(NH2)2, which was characterized by single-crystal X-ray diffraction. The complex contains discrete penta­amine­copper(II) units in a square-based pyramidal geometry. The overall structure of the multi-component crystal is dictated by hydrogen bonding between urea mol­ecules and amine H atoms with chloride anions.

The synthesis, crystallization and characterization of a tri­fluoro­methane­sulfonate salt of 5,10,15,20-tetra­kis­(1-benzyl­pyridin-1-ium-4-yl)-21H,23H-por­phy­rin, C68H54N84+·4CF3SO3−·4H2O, 1·OTf, are reported in this work. The reaction between 5,10,15,20-tetra­kis­(pyridin-4-yl)-21H,23H-porphyrin and benzyl bromide in the presence of 0.1 equiv. of Ca(OH)2 in CH3CN under reflux with an N2 atmosphere and subsequent treatment with silver tri­fluoro­methane­sulfonate (AgOTf) salt produced a red–brown solution. This reaction mixture was filtered and the solvent was allowed to evaporate at room temperature for 3 d to give 1·OTf. Crystal structure determination by single-crystal X-ray diffraction (SCXD) revealed that 1·OTf crystallizes in the space group P21/c. The asymmetric unit contains half a porphyrin mol­ecule, two tri­fluoro­methane­sulfonate anions and two water mol­ecules of crystallization. The macrocycle of tetra­pyrrole moieties is planar and unexpectedly it has coordinated CaII ions in occupational disorder. This CaII ion has only 10% occupancy (C72H61.80Ca0.10F12N8O16S4). The pyridinium rings bonded to methyl­ene groups from porphyrin are located in two different arrangements in almost orthogonal positions between the plane formed by the porphyrin and the pyridinium rings. The crystal structure features cation⋯π inter­actions between the CaII atom and the π-system of the phenyl ring of neighboring mol­ecules. Both tri­fluoro­methane­sulfonate anions are found at the periphery of 1, forming hydrogen bonds with water mol­ecules.

Three organoplatinum(II) complexes bearing natural aryl­olefin and quinoline derivatives, namely, [4-meth­oxy-5-(2-meth­oxy-2-oxoeth­oxy)-2-(prop-2-en-1-yl)phen­yl](quinolin-8-olato)platinum(II), [Pt(C13H15O4)(C9H6NO)], (I), [4-meth­oxy-5-(2-oxo-2-propoxyeth­oxy)-2-(prop-2-en-1-yl)phen­yl](quinoline-2-carboxy­l­ato)platinum(II), [Pt(C15H19O4)(C10H6NO2)], (II), and chlorido­[4-meth­oxy-5-(2-oxo-2-propoxyeth­oxy)-2-(prop-2-en-1-yl)phen­yl](quinoline)­plat­inum(II), [Pt(C15H19O4)Cl(C9H7N)], (III), were synthesized and structurally characterized by IR and 1H NMR spectroscopy, and by single-crystal X-ray diffraction. The results showed that the cyclo­platinated aryl­olefin coordinates with PtII via the carbon atom of the phenyl ring and the C=Colefinic group. The deprotonated 8-hy­droxy­quinoline (C9H6NO) and quinoline-2-carb­oxy­lic acid (C10H6NO2) coordinate with the PtII atom via the N and O atoms in complexes (I) and (II) while the quinoline (C9H7N) coordinates via the N atom in (III). Moreover, the coordinating N atom in complexes (I)–(III) is in the cis position compared to the C=Colefinic group. The crystal packing is characterized by C—H⋯π, C—H⋯O [for (II) and (III)], C—H⋯Cl [for (III) and π–π [for (I)] inter­actions.

Title compound 1Ni, [Ni(C46H32N4O2)], a secochlorin nickel complex, was prepared by diol cleavage of a precursor trans-di­hydroxy­dimethyl­chlorin. Two crystallographically independent mol­ecules in the structure are related by pseudo-A lattice centering, with mol­ecules differing mainly by a rotation of one of the acetyls and an adjacent phenyl groups. The two mol­ecules have virtually identical conformations characterized by noticeable in-plane deformation in the A1g mode and a prominent out-of-plane deformation in the B1u (ruffling) mode. Directional inter­actions between mol­ecules are scarce, limited to just a few C—H⋯O contacts, and inter­molecular inter­actions are mostly dispersive in nature.

In the title compound, C19H17NO5S, the cyclo­hexene ring adopts nearly an envelope conformation. In the crystal, mol­ecules are linked by C—H⋯O hydrogen bonds, forming a three-dimensional network. In addition, C—H⋯π inter­actions connect the mol­ecules by forming layers parallel to the (010) plane. According to the Hirshfeld surface analysis, H⋯H (36.9%), O⋯H/H⋯O (31.0%), C⋯H/H⋯C (18.9%) and S⋯H/H⋯S (7.9%) inter­actions are the most significant contributors to the crystal packing.

Crystal formation of penta­sodium nona­deca­cesium tetra­cosa­tungstate(VI) heneikosahydrate, Na5Cs19[W24O84]·21H2O, was successfully achieved by the conversion of [H2W12O42]10− through the addition of excess Cs+. The crystal structure comprising the toroidal isopolyoxidometalate is presented, as well as its Raman spectrum. Na5Cs19(H2O)21W24O84 crystallizes in the rhombohedral space group Roverline{3} with an obverse centering. The title compound represents the addition of a new member to the isopolytungstate family with mixed alkali counter-ions and contains rarely observed five-coordinate tungsten(VI) atoms in the [W24O84]24− anion (site symmetry C3i) arising from the conversion mediated by Cs+ counter-ions.

The structural characterization is reported of the supra­molecular complex between the tetra­quinoxaline-based cavitand 2,8,14,20-tetra­hexyl-6,10:12,16:18,22:24,4-O,O'-tetra­kis­(quinoxaline-2,3-di­yl)calix[4]resorcinarene (QxCav) with benzo­nitrile. The complex, of general formula C84H80N8O8·2C7H5N, crystallizes in the space group Poverline{1} with two independent mol­ecules in the asymmetric unit, displaying very similar geometrical parameters. For each complex, one of the benzo­nitrile mol­ecules is engulfed inside the cavity, while the other is located among the alkyl legs at the lower rim. The host and the guests mainly inter­act through weak C—H⋯π, C—H⋯N and dispersion inter­actions. These inter­actions help to consolidate the formation of supra­molecular chains running along the crystallographic b-axis direction.

Three new 1H-indole derivatives, namely, 2-(bromo­meth­yl)-3-methyl-1-(phenyl­sulfon­yl)-1H-indole, C16H14BrNO2S, (I), 2-[(E)-2-(2-bromo-5-meth­oxy­phen­yl)ethen­yl]-3-methyl-1-(phenyl­sulfon­yl)-1H-indole, C24H20BrNO3S, (II), and 2-[(E)-2-(2-bromo­phen­yl)ethen­yl]-3-methyl-1-(phenyl­sulfon­yl)-1H-indole, C23H18BrNO2S, (III), exhibit nearly orthogonal orientations of their indole ring systems and sulfonyl-bound phenyl rings. Such conformations are favourable for inter­molecular bonding involving sets of slipped π–π inter­actions between the indole systems and mutual C—H⋯π hydrogen bonds, with the generation of two-dimensional monoperiodic patterns. The latter are found in all three structures, in the form of supra­molecular columns with every pair of successive mol­ecules related by inversion. The crystal packing of the compounds is additionally stabilized by weaker slipped π–π inter­actions between the outer phenyl rings (in II and III) and by weak C—H⋯O, C—H⋯Br and C—H⋯π hydrogen bonds. The structural significance of the different kinds of inter­actions agree with the results of a Hirshfeld surface analysis and the calculated inter­action energies. In particular, the largest inter­action energies (up to −60.8 kJ mol−1) are associated with pairing of anti­parallel indole systems, while the energetics of weak hydrogen bonds and phenyl π–π inter­actions are comparable and account for 13–34 kJ mol−1.

The title compound, [Co(NCS)2(C6H7N)4] or Co(NCS)2(4-methyl­pyridine)4, was prepared by the reaction of Co(NCS)2 with 4-methyl­pyridine in water and is isotypic to one of the polymorphs of Ni(NCS)2(4-methyl­pyridine)4 [Kerr & Williams (1977). Acta Cryst. B33, 3589–3592 and Soldatov et al. (2004). Cryst. Growth Des. 4, 1185–1194]. Comparison of the experimental X-ray powder pattern with that calculated from the single-crystal data proves that a pure phase has been obtained. The asymmetric unit consists of one CoII cation, two crystallographically independent thio­cyanate anions and four independent 4-meth­yl­pyridine ligands, all located in general positions. The CoII cations are sixfold coordinated to two terminally N-bonded thio­cyanate anions and four 4-methyl­pyridine coligands within slightly distorted octa­hedra. Between the complexes, a number of weak C—H⋯N and C—H⋯S contacts are found. This structure represent a polymorphic modification of Co(NCS)2(4-methyl­pyridine)4 already reported in the CCD [Harris et al. (2003). NASA Technical Reports, 211890]. In contrast to this form, the crystal structure of the new polymorph shows a denser packing, indicating that it is thermodynamically stable at least at low temperatures. Thermogravimetric and differential thermoanalysis reveal that the title compound starts to decomposes at about 100°C and that the coligands are removed in separate steps without any sign of a polymorphic transition before decomposition.

This title compound, C20H26O2, was isolated from the benzene fraction of the stem bark of Staudtia kamerunensis Warb. (Myristicaceae) using column chromatography techniques over silica gel. The compound was fully characterized by single-crystal X-ray diffraction, one and two-dimensional NMR spectroscopy, IR and MS spectrometry. The compound has two fused cyclo­hexane rings attached to a benzene ring, with a carb­oxy­lic acid on C-4. This cyclo­hexene ring has a chair conformation while the other adopts a half-chair conformation. The benzene ring is substituted with a propenyl moiety. The structure is characterized by inter­molecular O—H⋯O hydrogen bonds, two C—H⋯O intra­molecular hydrogen bonds and two C—H⋯π inter­actions. The mol­ecular structure confirms previous studies carried out by spectroscopic techniques.

3-Phenyl-2-(thio­phen-3-yl)-2,3-di­hydro-4H-pyrido[3,2-e][1,3]thia­zin-4-one (C17H12N2OS2, 1) and 2-(1H-indol-3-yl)-3-phenyl-2,3-di­hydro-4H-pyrido[3,2-e][1,3]thia­zin-4-one 0.438-hydrate (C21H15N3OS·0.438H2O, 2) crystallize in space groups P21/n and C2/c, respectively. The asymmetric unit in each case is comprised of two parent mol­ecules, albeit of mixed chirality in the case of 1 and of similar chirality in 2 with the enanti­omers occupying the neighboring asymmetric units. Structure 2 also has water mol­ecules (partial occupancies) that form continuous channels along the b-axis direction. The thia­zine rings in both structures exhibit an envelope conformation. Inter­molecular inter­actions in 1 are defined only by C—H⋯O and C—H⋯N hydrogen bonds between crystallographically independent mol­ecules. In 2, hydrogen bonds of the type N—H⋯O between independent mol­ecules and C—H⋯N(π) type, and π–π stacking inter­actions between the pyridine rings of symmetry-related mol­ecules are observed.

The reaction of CoBr2, KNCSe and 2-methyl­pyridine N-oxide (C6H7NO) in ethanol leads to the formation of crystals of [Co(NCSe)2(C6H7NO)3] (1) and [Co(NCSe)2(C6H7NO)4] (2) from the same reaction mixture. The asymmetric unit of 1 is built up of one CoII cation, two NCSe− iso­seleno­cyanate anions and three 2-methyl­pyridine N-oxide coligands, with all atoms located on general positions. The asymmetric unit of 2 consists of two cobalt cations, four iso­seleno­canate anions and eight 2-methyl­pyridine N-oxide coligands in general positions, because two crystallographically independent complexes are present. In compound 1, the CoII cations are fivefold coordinated to two terminally N-bonded anionic ligands and three 2-methyl­pyridine N-oxide coligands within a slightly distorted trigonal–bipyramidal coordination, forming discrete complexes with the O atoms occupying the equatorial sites. In compound 2, each of the two complexes is coordinated to two terminally N-bonded iso­seleno­cyanate anions and four 2-methyl­pyridine N-oxide coligands within a slightly distorted cis-CoN2O4 octa­hedral coordination geometry. In the crystal structures of 1 and 2, the complexes are linked by weak C—H⋯Se and C—H⋯O contacts. Powder X-ray diffraction reveals that neither of the two compounds were obtained as a pure crystalline phase.

The crystal structures of 2-[1'-(carb­oxy­meth­yl)-4,4'-bi­pyridine-1,1'-diium-1-yl]acetate tetra­fluoro­borate, C14H13N2O4+·BF4− or (Hbcbpy)(BF4), and neutral 1,1'-bis­(carboxyl­atometh­yl)-4,4'-bi­pyridine-1,1'-diium (bcbpy), C14H20N2O8, are reported. The asymmetric unit of the (Hbcbpy)(BF4) consists of a Hbcbpy+ monocation, a BF4− anion, and one-half of a water mol­ecule. The BF4− anion is disordered. Two pyridinium rings of the Hbcbpy+ monocation are twisted at a torsion angle of 30.3 (2)° with respect to each other. The Hbcbpy monocation contains a carb­oxy­lic acid group and a deprotonated carboxyl­ate group. Both groups exhibit both a long and a short C—O bond. The cations are linked by inter­molecular hydrogen-bonding inter­actions between the carb­oxy­lic acid and the deprotonated carboxyl­ate group to give one-dimensional zigzag chains. The asymmetric unit of the neutral bcbpy consists of one-half of the bcbpy and two water mol­ecules. In contrast to the Hbcbpy+ monocation, the neutral bcbpy mol­ecule contains two pyridinium rings that are coplanar with each other and a carboxyl­ate group with similar C—O bond lengths. The mol­ecules are connected by inter­molecular hydrogen-bonding inter­actions between water mol­ecules and carboxyl­ate groups, forming a three-dimensional hydrogen-bonding network.

In the title mol­ecular salt, (C12H14N2)[CoCl4], the dihedral angle between the pyridine rings of the cation is 52.46 (9)° and the N—C—C—N torsion angle is −128.78 (14)°, indicating that the ring nitro­gen atoms are in anti-clinal conformation. The Cl—Co—Cl bond angles in the anion span the range 105.46 (3)–117.91 (2)°. In the extended structure, the cations and anions are linked by cation-to-anion N—H⋯Cl and C—H⋯Cl inter­actions, facilitating the formation of R44(18) and R44(20) ring motifs. Furthermore, the crystal structure features weak anion-to-cation Cl⋯π inter­actions [Cl⋯π = 3.4891 (12) and 3.5465 (12) Å]. Hirshfeld two-dimensional fingerprint plots revealed that the most significant inter­actions are Cl⋯H/H⋯Cl (45.5%), H⋯H (29.0%), Cl⋯C/C⋯Cl (7.8%), Cl⋯N/N⋯Cl (3.5%), Cl⋯Cl (1.4) and Co⋯H (1%) contacts.

The title compound, systematic name tris­(μ2-perfluoro-o-phenyl­ene)(μ2-3-phenyl-4H-chromen-4-one)-triangulo-trimercury, [Hg3(C6F4)3(C15H10O2)], crystallizes in the monoclinic P21/n space group with one flavone (FLA) and one cyclic trimeric perfluoro-o-phenyl­enemercury (TPPM) mol­ecule per asymmetric unit. The FLA mol­ecule is located on one face of the TPPM acceptor and is linked in an asymmetric coordination of its carbonyl oxygen atom with two Hg centers of the TPPM macrocycle. The angular-shaped complexes pack in zigzag chains where they stack via two alternating TPPM–TPPM and FLA–FLA stacking patterns. The distance between the mean planes of the neighboring TPPM macrocycles in the stack is 3.445 (2) Å, and that between the benzo-γ-pyrone moieties of FLA is 3.328 (2) Å. The neighboring stacks are inter­digitated through the shortened F⋯F, CH⋯F and CH⋯π contacts, forming a dense crystal structure.

Bis(2-methyl­pyridine)­gold(I) di­bromido­aurate(I), [Au(C6H7N)2][AuBr2], (1), crystallizes in space group C2/c with Z = 4. Both gold atoms lie on twofold axes and are connected by an aurophilic contact. A second aurophilic contact leads to infinite chains of alternating cations and anions parallel to the b axis, and the residues are further connected by a short H⋯Au contact and a borderline Br⋯Br contact. Bis(3-methyl­pyridine)­gold(I) di­bromido­aurate(I), [Au(C6H7N)2][AuBr2], (2), crystallizes in space group C2/m with Z = 2. Both gold atoms lie on special positions with symmetry 2/m and are connected by an aurophilic contact; all other atoms except for one methyl hydrogen lie in mirror planes. The extended structure is closely analogous to that of 1, although the structures are formally not isotypic. Bis(3,5-di­methyl­pyridine)­gold(I) di­chlor­ido­aurate(I), [Au(C7H9N)2][AuCl2], (3) crystallizes in space group Poverline{1} with Z = 2. The cation lies on a general position, and there are two independent anions in which the gold atoms lie on inversion centres. The cation and one anion associate via three short H⋯Cl contacts to form a ribbon structure parallel to the b axis; aurophilic contacts link adjacent ribbons. Bis(3,5-di­methyl­pyridine)­gold(I) di­bromido­aurate(I), [Au(C7H9N)2][AuBr2], (4) is isotypic to 3. Attempts to make similar compounds involving 2-bromo­pyridine led instead to 2-bromopyridinium di­bromido­aurate(I)–2-bromo­pyridine (1/1), (C5H5BrN)[AuBr2]·C5H4BrN, (5), which crystallizes in space group Poverline{1} with Z = 2; all atoms lie on general positions. The 2-bromo­pyridinium cation is linked to the 2-bromo­pyridine mol­ecule by an N—H⋯N hydrogen bond. Two formula units aggregate to form inversion-symmetric dimers involving Br⋯Br, Au⋯Br and H⋯Br contacts.

The synthesis, crystal structure, and a Hirshfeld surface analysis of tris­{N,N-diethyl-N'-[(4-nitro­phen­yl)(oxo)meth­yl]carbamimido­thio­ato}cobalt(III) conducted at 180 K are presented. The complex consists of three N,N-diethyl-N'-[(4-nitro­benzene)(oxo)meth­yl]carbamimido­thio­ato ligands, threefold sym­metric­ally bonded about the CoIII ion, in approximately octa­hedral coordination, which generates a triple of individually near planar metallacyclic (Co—S—C—N—C—O) rings. The overall geometry of the complex is determined by the mutual orientation of each metallacycle about the crystallographically imposed threefold axis [dihedral angles = 81.70 (2)°] and by the dihedral angles between the various planar groups within each asymmetric unit [metallacycle to benzene ring = 13.83 (7)°; benzene ring to nitro group = 17.494 (8)°]. The complexes stack in anti-parallel columns about the overline{3} axis of the space group (Poverline{3}), generating solvent-accessible channels along [001]. These channels contain ill-defined, multiply disordered, partial-occupancy solvent. Atom–atom contacts in the crystal packing predominantly (∼96%) involve hydrogen, the most abundant types being H⋯H (36.6%), H⋯O (31.0%), H⋯C (19.2%), H⋯N (4.8%), and H⋯S (4.4%).

The oxidation of me­thionyl peptides can contribute to increased biological (oxidative) stress and development of various inflammatory diseases. The conformation of peptides has an important role in the mechanism of oxidation and the inter­mediates formed in the reaction. Herein, the crystal structures of the isomeric dipeptides Gly-Met (Gly = glycine and Met = me­thio­nine) and Met-Gly, both C7H14N2O3S, are reported. Both mol­ecules exist in the solid state as zwitterions with nominal proton transfer from the carb­oxy­lic acid to the primary amine group. The Gly-Met mol­ecule has an extended backbone structure, while Met-Gly has two nearly planar regions kinked at the C atom bearing the NH3 group. In the crystals, both structures form extensive three-dimensional hydrogen-bonding networks via N—H⋯O and bifurcated N—H⋯(O,O) hydrogen bonds having N⋯O distances in the range 2.6619 (13)–2.8513 (13) Å for Gly-Met and 2.6273 (8)–3.1465 (8) Å for Met-Gly.

Crystal formation of caesium thallium chloride phospho­tungstates, Cs9(TlCl6)(PW12O40)2·9CsCl showcases the ability to capture and crystallize octa­hedral complexes via the use of polyoxometalates (POMs). The large number of caesium chlorides allows for the POM [α-PW12O40]3− to arrange itself in a cubic close-packing lattice extended framework, in which the voids created enable the capture of the [TlCl6]3− complex.

This study presents the synthesis, characterization and Hirshfeld surface analysis of a small organic ammonium salt, C2H7BrN+·Br−. Small cations like the one in the title compound are considered promising components of hybrid perovskites, crucial for optoelectronic and photovoltaic applications. While the incorporation of this organic cation into various hybrid perovskite structures has been explored, its halide salt counterpart remains largely uninvestigated. The obtained structural results are valuable for the synthesis and phase analysis of hybrid perovskites. The title compound crystallizes in the solvent-free form in the centrosymmetric monoclinic space group P21/c, featuring one organic cation and one bromide anion in its asymmetric unit, with a torsion angle of −64.8 (2)° between the ammonium group and the bromine substituent, positioned in a gauche conformation. The crystal packing is predominantly governed by Br⋯H inter­actions, which constitute 62.6% of the overall close atom contacts.

The title compound, [Re(C17H22N3O2S)(CO)3] is a net neutral fac-Re(I)(CO)3 complex of the 4-methyl­biphenyl sulfonamide derivatized di­ethyl­enetri­amine ligand. The NNN-donor monoanionic ligand coordinates with the Re core in tridentate fashion, establishing an inner coordination sphere resulting in a net neutral complex. The complex possesses pseudo-octa­hedral geometry where one face of the octa­hedron is occupied by three carbonyl ligands and the other faces are occupied by one sp2 nitro­gen atom of the sulfonamide group and two sp3 nitro­gen atoms of the dien backbone. The Re—Nsp2 bond distance, 2.173 (4) Å, is shorter than the Re—Nsp3 bond distances, 2.217 (5) and 2.228 (6) Å, and is similar to the range reported for typical Re—Nsp2 bond lengths (2.14 to 2.18 Å).

The mol­ecular structure of tricarbon­yl[η4-6-exo-(tri­phenyl­phosphino)cyclo­hepta-2,4-dien-1-one]iron(0) tetra­fluoro­borate di­chloro­methane hemisolvate, [Fe(C28H22O4)(CO)3]BF4·0.5CH2Cl2, as determined by single-crystal X-ray diffraction is reported. The two independent tricarbon­yl[η4-6-exo-(tri­phenyl­phosphino)cyclo­hepta-2,4-dien-1-one] iron(0) cations and their corresponding anions form dimers, which constitute the asymmetric unit of the structure parallel to the (100) plane. Solid-state stability within that asymmetric unit as well as between neighboring dimeric units is afforded by C—H⋯O and C—H⋯F hydrogen bonds and C—H⋯π and Y—X⋯π (Y = B, C; X = F, O) inter­actions, which yield diperiodic sheets and a three-dimensional extended network.

The crystal structure of the title 2:1 mol­ecular complex between 2-(allyl­thio)­pyridine and 1,2,4,5-tetra­fluoro-3,6-di­iodo­benzene, C6F4I2·2C8H9NS, at 100 K has been determined in the monoclinic space group P21/c. The most noteworthy characteristic of the complex is the halogen bond between iodine and the pyridine ring with a short N⋯I contact [2.8628 (12) Å]. The Hirshfeld surface analysis shows that the hydrogen⋯hydrogen contacts dominate the crystal packing with a contribution of 32.1%.

A new mononuclear complex, penta­aqua­(cucurbit[6]uril-κ2O,O')(nitrato-κ2O,O')praseodymium(III) dinitrate 9.56-hydrate, [Pr(NO3)(CB6)(H2O)5](NO3)2·9.56H2O (1), was obtained as outcome of the hydro­thermal reaction between the macrocyclic ligand cucurbit[6]uril (CB6, C36H36N24O12) with a tenfold excess of Pr(NO3)3·6H2O. Complex 1 crystallizes in the P21/n space group with two crystallographically independent but chemically identical [Pr(CB6)(NO3)(H2O)5]2+ complex cations, four nitrate counter-anions and 19.12 inter­stitial water mol­ecules per asymmetric unit. The nona­coordinated PrIII in 1 are located in the PrO9 coordination environment formed by two carbonyl O atoms from bidentate cucurbit[6]uril units, two oxygen atoms from the bidentate nitrate anion and five water mol­ecules. Considering the differences in Pr—O bond distances and O—Pr—O angles in the coordination spheres, the coordination polyhedrons of the two PrIII atoms can be described as distorted spherical capped square anti­prismatic and muffin polyhedral.

The title compound, [Ni(NCS)2(C6H7N)2]n, was prepared by the reaction of Ni(NCS)2 with 4-methyl­pyridine in water. Its asymmetric unit consists of two crystallographically independent NiII cations, of which one is located on a twofold rotational axis whereas the second occupies a center of inversion, two independent thio­cyanate anions and two independent 4-methyl­pyridine co­ligands in general positions. Each NiII cation is octa­hedrally coordinated by two 4-methyl­pyridine coligands as well as two N- and two S-bonded thio­cyanate anions. One of the cations shows an all-trans, the other a cis–cis–trans configuration. The metal centers are linked by pairs of μ-1,3-bridging thio­cyanate anions into [101] chains. X-ray powder diffraction shows that a pure crystalline phase has been obtained and thermogravimetry coupled to differential thermoanalysis reveals that the title compound loses half of the 4-methyl­pyridine coligands and transforms into Ni(NCS)2(C6H7N). Nearly pure samples of this compound can be obtained by thermal annealing and a Rietveld refinement demonstrated that it is isotypic to its recently reported Cd analog [Neumann et al., (2020). CrystEngComm. 22, 184–194] In its crystal structure, the metal cations are linked by one μ-1,3(N,S)- and one μ-1,3,3(N,S,S)-bridging thio­cyanate anion into single chains that condense via the μ-1,3,3(N,S,S)-bridging anionic ligands into double chains.

The pyrazolo­pyrimidine moiety in the title mol­ecule, C13H12N4S, is planar with the methyl­sulfanyl substituent lying essentially in the same plane. The benzyl group is rotated well out of this plane by 73.64 (6)°, giving the mol­ecule an approximate L shape. In the crystal, C—H⋯π(ring) inter­actions and C—H⋯S hydrogen bonds form tubes extending along the a axis. Furthermore, there are π–π inter­actions between parallel phenyl rings with centroid-to-centroid distances of 3.8418 (12) Å. A Hirshfeld surface analysis of the crystal structure indicates that the most important contributions to the crystal packing are from H⋯H (47.0%), H⋯N/N⋯H (17.6%) and H⋯C/C⋯H (17.0%) inter­actions. The volume of the crystal voids and the percentage of free space were calculated to be 76.45 Å3 and 6.39%, showing that there is no large cavity in the crystal packing. Evaluation of the electrostatic, dispersion and total energy frameworks indicate that the cohesion of the crystal structure is dominated by the dispersion energy contributions.

A new quinoline derivative, namely, 6-(di­ethyl­amino)-4-phenyl-2-(pyridin-2-yl)quinoline, C24H23N3 (QP), and its MnII complex aqua-1κO-di-μ-chlorido-1:2κ4Cl:Cl-di­chlorido-1κCl,2κCl-bis­[6-(di­ethyl­amino)-4-phenyl-2-(pyridin-2-yl)quinoline]-1κ2N1,N2;2κ2N1,N2-dimanganese(II), [Mn2Cl4(C24H23N3)2(H2O)] (MnQP), were synthesized. Their compositions have been determined with ESI-MS, IR, and 1H NMR spectroscopy. The crystal-structure determination of MnQP revealed a dinuclear complex with a central four-membered Mn2Cl2 ring. Both MnII atoms bind to an additional Cl atom and to two N atoms of the QP ligand. One MnII atom expands its coordination sphere with an extra water mol­ecule, resulting in a distorted octa­hedral shape. The second MnII atom shows a distorted trigonal–bipyramidal shape. The UV–vis absorption and emission spectra of the examined compounds were studied. Furthermore, when investigating the aggregation-induced emission (AIE) properties, it was found that the fluorescent color changes from blue to green and eventually becomes yellow as the fraction of water in the THF/water mixture increases from 0% to 99%. In particular, these color and intensity changes are most pronounced at a water fraction of 60%. The crystal structure contains disordered solvent mol­ecules, which could not be modeled. The SQUEEZE procedure [Spek (2015). Acta Cryst. C71, 9–18] was used to obtain information on the type and qu­antity of solvent mol­ecules, which resulted in 44 electrons in a void volume of 274 Å3, corresponding to approximately 1.7 mol­ecules of ethanol in the unit cell. These ethanol mol­ecules are not considered in the given chemical formula and other crystal data.

The crystal structures of 4-benzyl-1H-pyrazole (C10H10N2, 1) and 3,5-di­amino-4-benzyl-1H-pyrazole (C10H12N4, 2) were measured at 150 K. Although its different conformers and atropenanti­omers easily inter­convert in solution by annular tautomerism and/or rotation of the benzyl substituent around the C(pyrazole)—C(CH2) single bond (as revealed by 1H NMR spectroscopy), 1 crystallizes in the non-centrosymmetric space group P21. Within its crystal structure, the pyrazole and phenyl aromatic moieties are organized into alternating bilayers. Both pyrazole and phenyl layers consist of aromatic rings stacked into columns in two orthogonal directions. Within the pyrazole layer, the pyrazole rings form parallel catemers by N—H⋯N hydrogen bonding. Compound 2 adopts a similar bilayer structure, albeit in the centrosymmetric space group P21/c, with pyrazole N—H protons as donors in N—H⋯π hydrogen bonds with neighboring pyrazole rings, and NH2 protons as donors in N—H⋯N hydrogen bonds with adjacent pyrazoles and other NH2 moieties. The crystal structures and supra­molecular features of 1 and 2 are contrasted with the two known structures of their analogs, 3,5-dimethyl-4-benzyl-1H-pyrazole and 3,5-diphenyl-4-benzyl-1H-pyrazole.

Reaction of thorium(IV) nitrate with 2-[(4-phenyl-1H-1,2,3-triazol-1-yl)meth­yl]pyridine (L) yielded (LH)2[Th(NO3)6] or (C14H13N4)2[Th(NO3)6] (1), instead of the expected mixed-ligand complex [Th(NO3)4L2], which was detected in the mass spectrum of 1. In the structure, the [Th(NO3)6]2− anions display an icosa­hedral coordination geometry and are connected by LH+ cations through C—H⋯O hydrogen bonds. The LH+ cations inter­act via N—H⋯N hydrogen bonds. Hirshfeld surface analysis indicates that the most important inter­actions are O⋯H/H⋯O hydrogen-bonding inter­actions, which represent a 55.2% contribution.

The reaction of cadmium iodide with 3-amino­pyrazole (3-apz) in ethano­lic solution leads to tautomerization of the ligand and the formation of crystals of the title compound, catena-poly[[di­iodido­cadmium(II)]-bis­(μ-3-amino-1H-pyrazole)-κ2N2:N3;κ2N3:N2], [CdI2(C3H5N3)2]n or [CdI2(3-apz)2]n. Its asymmetric unit consists of a half of a Cd2+ cation, an iodide anion and a 3-apz mol­ecule. The Cd2+ cations are coordinated by two iodide anions and two 3-apz ligands, generating trans-CdN4I2 octa­hedra, which are linked into chains by pairs of the bridging ligands. In the crystal, the ligand mol­ecules and iodide anions of neighboring chains are linked through inter­chain hydrogen bonds into a di-periodic network. The inter­molecular contacts were qu­anti­fied using Hirshfeld surface analysis and two-dimensional fingerprint plots, revealing the relative qu­anti­tative contributions of the weak inter­molecular contacts.

The asymmetric unit of the title compound is composed of two independent ion pairs of 4-(di­methyl­amino)­pyridin-1-ium 8-hy­droxy­quinoline-5-sulfonate (HDMAP+·HqSA−, C7H11N2+·C9H6NO4S−) and neutral N,N-di­methyl­pyridin-4-amine mol­ecules (DMAP, C7H10N2), co-crystallized as a 1:1:1 HDMAP+:HqSA−:DMAP adduct in the monoclinic system, space group Pc. The compound has a layered structure, including cation layers of HDMAP+ with DMAP and anion layers of HqSA− in the crystal. In the cation layer, there are inter­molecular N—H⋯N hydrogen bonds between the protonated HDMAP+ mol­ecule and the neutral DMAP mol­ecule. In the anion layer, each HqSA− is surrounded by other six HqSA−, where the planar network structure is formed by inter­molecular O—H⋯O and C—H⋯O hydrogen bonds. The cation and anion layers are linked by inter­molecular C—H⋯O hydrogen bonds and C—H⋯π inter­actions.

In the title complex, [U(C10H7N3O3)O2(CH3OH)]n, the UVI cation has a typical penta­gonal–bipyramidal environment with the equatorial plane defined by one N and two O atoms of one doubly deprotonated 2-[5-(2-hy­droxy­phen­yl)-1H-1,2,4-triazol-3-yl]acetic acid ligand, a carboxyl­ate O atom of the symmetry-related ligand and the O atom of the methanol mol­ecule [U—N/Oeq 2.256 (4)–2.504 (5) Å]. The axial positions are occupied by two oxide O atoms. The equatorial atoms are almost coplanar, with the largest deviation from the mean plane being 0.121 Å for one of the O atoms. The benzene and triazole rings of the tetra­dentate chelating–bridging ligand are twisted by approximately 21.6 (2)° with respect to each other. The carboxyl­ate group of the ligand bridges two uranyl cations, forming a neutral zigzag chain reinforced by a strong O—H⋯O hydrogen bond. In the crystal, adjacent chains are linked into two-dimensional sheets parallel to the ac plane by C/N—H⋯N/O hydrogen bonding and π–π inter­actions. Further weak C—H⋯O contacts consolidate the three-dimensional supra­molecular architecture. In the solid state, the compound shows a broad medium intensity LMCT transition centred around 463 nm, which is responsible for its red colour.

Two new [1-(phenyl­sulfon­yl)-1H-indol-2-yl]methanamine derivatives, namely, N-(3-meth­oxy­phen­yl)-N-{[1-(phenyl­sulfon­yl)-1H-indol-2-yl]meth­yl}acetamide, C24H22N2O4S, (I), and N-(2,5-di­meth­oxy­phen­yl)-N-{[1-(phenyl­sulfon­yl)-1H-indol-2-yl]meth­yl}benzene­sulfonamide, C29H26N2O6S2, (II), reveal a nearly orthogonal orientation of their indole ring systems and sulfonyl-bound phenyl rings. The sulfonyl moieties adopt the anti-periplanar conformation. For both compounds, the crystal packing is dominated by C—H⋯O bonding [C⋯O = 3.312 (4)–3.788 (8) Å], with the structure of II exhibiting a larger number, but weaker bonds of this type. Slipped π–π inter­actions of anti­parallel indole systems are specific for I, whereas the structure of II delivers two kinds of C—H⋯π inter­actions at both axial sides of the indole moiety. These findings agree with the results of Hirshfeld surface analysis. The primary contributions to the surface areas are associated with the contacts involving H atoms. Although II manifests a larger fraction of the O⋯H/H⋯O contacts (25.8 versus 22.4%), most of them are relatively distal and agree with the corresponding van der Waals separations.

The crystal structures of two inter­mediates, 4-amino-3,5-di­fluoro­benzo­nitrile, C7H4F2N2 (I), and ethyl 4-amino-3,5-di­fluoro­benzoate, C9H9F2NO2 (II), along with a visible-light-responsive azo­benzene derivative, diethyl 4,4'-(diazene-1,2-di­yl)bis­(3,5-di­fluoro­benzoate), C18H14F4N2O4 (III), obtained by four-step synthetic procedure, were studied using single-crystal X-ray diffraction. The mol­ecules of I and II demonstrate the quinoid character of phenyl rings accompanied by the distortion of bond angles related to the presence of fluorine substituents in the 3 and 5 (ortho) positions. In the crystals of I and II, the mol­ecules are connected by N—H⋯N, N—H⋯F and N—H⋯O hydrogen bonds, C—H⋯F short contacts, and π-stacking inter­actions. In crystal of III, only stacking inter­actions between the mol­ecules are found.

The dinuclear mol­ecule of the title compound, [Mo2(C9H13)2(CO)6] or [Mo(tBuCp)(CO)3]2 where tBu and Cp are tert-butyl and cyclo­penta­dienyl, is centrosymmetric and is characterized by an Mo—Mo bond length of 3.2323 (3) Å. Imposed by inversion symmetry, the tBuCp and the carbonyl ligands are in a transoid arrangement to each other. In the crystal, inter­molecular C—H⋯O contacts lead to the formation of layers parallel to the bc plane.

Single crystals of the mol­ecular compound, {Cu20Ir6Cl8(C21H24N2)6(C4H4N2)3]·3.18CH3OH or [({Cu10Ir3}Cl4(IMes)3(pyrazine))2(pyrazine)]·3.18CH3OH [where IMes is 1,3-bis­(2,4,6-trimethylphen­yl)imidazol-2-yl­idene], with a unique heterometallic cluster have been prepared and the structure revealed using single-crystal X-ray diffraction. The mol­ecule is centrosymmetric with two {Cu10Ir3} cores bridged by a pyrazine ligand. The polymetallic cluster contains three stabilizing N-heterocyclic carbenes, four Cl ligands, and a non-bridging pyrazine ligand. Notably, the Cu—Ir core is arranged in an unusual shape containing 13 vertices, 22 faces, and 32 sides. The atoms within the trideca­metallic cluster are arranged in four planes, with 2, 4, 4, 3 metals in each plane. Ir atoms are present in alternate planes with an Ir atom featuring in the peripheral bimetallic plane, and two Ir atoms featuring on opposite sides of the non-adjacent tetra­metallic plane. The crystal contains two disordered methanol solvent mol­ecules with an additional region of non-modelled electron density corrected for using the SQUEEZE routine in PLATON [Spek (2015). Acta Cryst. C71, 9–18]. The given chemical formula and other crystal data do not take into account the unmodelled methanol solvent mol­ecule(s).

The structures of seven gold(III) halide derivatives of general formula LAuX3 (L = methyl­pyridines or di­methyl­pyridines, X = Cl or Br) are presented: tri­chlorido­(2-methyl­pyridine)­gold(III), [AuCl3(C6H7N)], 1 (as two polymorphs 1a and 1b); tri­bromido­(2-methyl­pyridine)­gold(III), [AuBr3(C6H7N)], 2; tri­bromido­(3-methyl­pyridine)­gold(III), [AuBr3(C6H7N)], 3; tri­bromido­(2,4-di­meth­yl­pyridine)­gold(III), [AuBr3(C7H9N)], 4; tri­chlorido­(3,5-di­methylpyridine)­gold(III), [AuCl3(C7H9N)], 5; tri­bromido­(3,5-di­methyl­pyridine)­gold(III), [AuBr3(C7H9N)], 6, and tri­chlorido­(2,6-di­methyl­pyridine)­gold(III), [AuCl3(C7H9N)], 7. Additionally, the structure of 8, the 1:1 adduct of 2 and 6, [AuBr3(C6H7N)]·[AuBr3(C7H9N)], is included. All the structures crystallize solvent-free, and all have Z' = 1 except for 5 and 7, which display crystallographic twofold rotation symmetry, and 4, which has Z' = 2. 1a and 2 are isotypic. The coordination geometry at the gold(III) atoms is, as expected, square-planar. Four of the crystals (1a, 1b, 2 and 8) were non-merohedral twins, and these structures were refined using the ‘HKLF 5’ method. The largest inter­planar angles between the pyridine ring and the coordination plane are observed for those structures with a 2-methyl substituent of the pyridine ring. The Au—N bonds are consistently longer trans to Br (average 2.059 Å) than trans to Cl (average 2.036 Å). In the crystal packing, a frequent feature is the offset-stacked and approximately rectangular dimeric moiety (Au—X)2, with anti­parallel Au—X bonds linked by Au⋯X contacts at the vacant positions axial to the coordination plane. The dimers are connected by further secondary inter­actions (Au⋯X or X⋯X contacts, `weak' C—H⋯X hydrogen bonds) to form chain, double chain (`ladder') or layer structures, and in several cases linked again in the third dimension. Only 1b and 7 contain no offset dimers; these structures instead involve C—H⋯Cl hydrogen bonds combined with Cl⋯Cl contacts (1b) or Cl⋯π contacts (7). The packing patterns of seven further complexes LAuX3 involving simple pyridines (taken from the Cambridge Structural Database) are compared with those of 1–8.

The di­hydro­imidazole ring in the title mol­ecule, C20H20N2O3S, is slightly distorted and the lone pair on the tri-coordinate nitro­gen atom is involved in intra-ring π bonding. The methyl­sulfanyl substituent lies nearly in the plane of the five-membered ring while the ester substituent is rotated well out of that plane. In the crystal, C—H⋯O hydrogen bonds form inversion dimers, which are connected along the a- and c-axis directions by additional C—H⋯O hydrogen bonds, forming layers parallel to the ac plane. The major contributors to the Hirshfeld surface are C⋯H/H⋯C, O⋯H/H⋯O and S⋯H/H⋯S contacts at 20.5%, 14.7% and 4.9%, respectively.