[μ-N,N′-Bis(pyridin-3-yl)benzene-1,4-dicarboxamide-<!?show [forcelb]><!?tlsb=0.12pt>1:2κ²N:N′]bis{[N,N′-bis(pyridin-3-yl)benzene-1,4-dicarboxamide-κN]diiodidomercury(II)}, [Hg₂I₄(C₁₈H₁₄N₄O₂)₃], is an S-shaped dinuclear molecule, composed of two HgI₂ units and three N,N′-bis(pyridin-3-yl)benzene-1,4-dicarboxamide (L) ligands. The central L ligand is centrosymmetric and coordinated to two Hg^II cations via two pyridine N atoms, in a syn–syn conformation. The two terminal L ligands are monodentate, with one uncoordinated pyridine N atom, and each adopts a syn–anti conformation. The HgI₂ units show highly distorted tetrahedral (sawhorse) geometry, as the Hg^II centres lie only 0.34 (2) or 0.32 (2) Å from the planes defined by the I and pyridine N atoms. Supramolecular interactions, thermal stability and solid-state luminescence properties were also measured.

The title compound, C₁₀H₁₁BrO₄, a useful precursor to pharmaceutically active isocoumarin and isochroman derivatives, crystallizes with two unique molecules in the asymmetric unit. A π–π stacking interaction links the planar molecules in the asymmetric unit. Additional π–π contacts stack pairs of molecules along the c axis. A feature of the crystal packing is the presence of a number of short Br...O contacts. A particularly unusual arrangement involves the formation of dimers, with pairs of Br...O contacts imposing a close Br...Br interaction and generating five-membered rings within an eight-membered ring formed by two Br...O contacts. Only two comparable arrangements have been reported previously. The Br...O contacts combine with weak C—H...O hydrogen bonds to form corrugated sheets of molecules approximately parallel to (001). These sheets are stacked along the c axis by π–π interactions to generate a three-dimensional network.

In the title complex, [PdCl₂(C₁₂H₂₂S₃)]·0.8CH₃CN, a potentially tridentate thioether ligand coordinates in a cis-bidentate manner to yield a square-planar environment for the Pd^II cation [mean deviation of the Pd from the Cl₂S₂ plane = 0.0406 (7) Å]. Each square-planar entity packs in an inverse face-to-face manner, giving pairs with plane-to-plane separations of 3.6225 (12) Å off-set by 1.1263 (19) Å, with a Pd...Pd separation of 3.8551 (8) Å. A partial acetonitrile solvent molecule is present. The occupancy of this molecule was allowed to refine, and converged to 0.794 (10). The synthesis of the previously unreported 3,6,9-trithiabicyclo[9.3.1]pentadecane ligand is also outlined.

The molecules of 3-amino-4-anilino-1H-isochromen-1-one, C₁₅H₁₂N₂O₂, (I), and 3-amino-4-[methyl(phenyl)amino]-1H-isochromen-1-one, C₁₆H₁₄N₂O₂, (II), adopt very similar conformations, with the substituted amino group PhNR, where R = H in (I) and R = Me in (II), almost orthogonal to the adjacent heterocyclic ring. The molecules of (I) are linked into cyclic centrosymmetric dimers by pairs of N—H...O hydrogen bonds, while those of (II) are linked into complex sheets by a combination of one three-centre N—H...(O)₂ hydrogen bond, one two-centre C—H...O hydrogen bond and two C—H...π(arene) hydrogen bonds.

A new 3d–4f heterometallic polymer, poly[[aqua-μ₃-chlorido-[μ₃-4-(pyridin-4-yl)benzoato]tris[μ₂-4-(pyridin-4-yl)benzoato]dicopper(I)erbium(III)] dihydrate], {[Cu₂Er(C₁₂H₈NO₂)₄Cl(H₂O)]·2H₂O}_n, was synthesized by the hydrothermal reaction of Er₂O₃, CuCl₂·2H₂O and 4-(pyridin-4-yl)benzoic acid in the presence of HClO₄. The asymmetric unit contains one Er³⁺ cation, two Cu⁺ cations, one Cl⁻ anion, four deprotonated 4-(pyridin-4-yl)benzoate ligands, one coordinated aqua ligand and two solvent water molecules. This tubular one-dimensional polymer is constructed from alternating clusters of europium(III)–water and copper(I) chloride bridged by 4-(pyridin-4-yl)benzoate ligands. Extensive hydrogen-bonding interactions involving both the coordinated and the solvent water molecules provide further stabilization to the structure.

Bis(4-picoline-κN)gold(I) dibromidoaurate(I), [Au(C₆H₇N)₂][AuBr₂], (I), crystallizes in the monoclinic space group P2₁/n, with two half cations and one general anion in the asymmetric unit. The cations, located on centres of inversion, assemble to form chains parallel to the a axis, but there are no significant contacts between the cations. Cohesion is provided by flanking anions, which are connected to the cations by short Au...Au contacts and C—H...Br hydrogen bonds, and to each other by Br...Br contacts. The corresponding chloride derivative, [Au(C₆H₇N)₂][AuCl₂], (II), is isotypic. A previous structure determination of (II), reported in the space group P with very similar axis lengths to those of (I) [Lin et al. (2008). Inorg. Chem.47, 2543–2551], might be identical to the structure presented here, except that its γ angle of 88.79 (7)° seems to rule out a monoclinic cell. No phase transformation of (II) could be detected on the basis of data sets recorded at 100, 200 and 295 K.

Two copper complex solvatomorphs, namely (3,10-C-meso-3,5,7,7,10,12,14,14-octamethyl-1,4,8,11-tetraazacyclotetradecane)bis(perchlorato-κO)copper(II) 1.2-hydrate, [Cu(ClO₄)₂(C₁₈H₄₀N₄)]·1.2H₂O, (I), and (3,10-C-meso-3,5,7,7,10,12,14,14-octamethyl-1,4,8,11-tetraazacyclotetradecane)bis(perchlorato-κO)copper(II), [Cu(ClO₄)₂(C₁₈H₄₀N₄)], (II), are described and compared with each other and with a third, already reported, anhydrous diastereomer, denoted (III). Both compounds present very similar centrosymmetic coordination environments, with the Cu^II cation lying on an inversion centre in a distorted 4+2 octahedral environment, defined by the macrocyclic N₄ group in the equatorial sites and two perchlorate groups in trans-axial positions [one of the perchlorate ligands in (I) is partially disordered]. The most significant difference in molecular shape is seen in the orientation of the perchlorate anions, and the influence of this on the intramolecular hydrogen bonding is discussed. The (partially) hydrated state of (I) favours the formation of chains along [011], while the anhydrous character of (II) and (III) promotes loosely bound structures with low packing indices.

The molecules of both methyl 4-[2-(4-chlorobenzoyl)hydrazinyl]-3-nitrobenzoate, C₁₅H₁₂ClN₃O₅, (I), and methyl 4-[2-(2-fluorobenzoyl)hydrazinyl]-3-nitrobenzoate, C₁₅H₁₂FN₃O₅, (II), contain an intramolecular N—H...O hydrogen bond, and both show electronic polarization in the nitrated aryl ring. In both compounds, molecules are linked by a combination of N—H...O and C—H...O hydrogen bonds to form sheets, which are built from R₄³(18) rings in (I) and from R₄⁴(28) rings in (II). In each of methyl 3-phenyl-1,2,4-benzotriazine-6-carboxylate, C₁₅H₁₁N₃O₂, (III), and methyl 3-(4-methylphenyl)-1,2,4-benzotriazine-6-carboxylate, C₁₆H₁₃N₃O₂, (IV), the benzotriazine unit shows naphthalene-type delocalization. There are no hydrogen bonds in the structures of compounds (III) and (IV), but in both compounds, the molecules are linked into chains by π–π stacking interactions involving the benzotriazine units. The mechanism of chain formation is the same in both (III) and (IV), and the different orientations of the two chains can be related to the approximate relationship between the unit-cell metrics for (III) and (IV).

The crystal structures of three new solvates of olanzapine [systematic name: 2-methyl-4-(4-methylpiperazin-1-yl)-10H-thieno[2,3-b][1,5]benzodiazepine], namely olanzapine acetic acid monosolvate, C₁₇H₂₀N₄S·C₂H₄O₂, (I), olanzapine propan-2-ol hemisolvate monohydrate, C₁₇H₂₀N₄S·0.5C₃H₈O·H₂O, (II), and olanzapine propan-2-one hemisolvate monohydrate, C₁₇H₂₀N₄S·0.5C₃H₆O·H₂O, (III), are presented and compared with other known olanzapine forms. There is a fairly close resemblance of the molecular conformation for all studied analogues. The crystal structures are built up through olanzapine dimers, which are characterized via C—H...π interactions between the aliphatic fragment (1-methylpiperazin-4-yl) and the aromatic fragment (benzene system). All solvent (guest) molecules participate in hydrogen-bonding networks. The crystal packing is sustained via intermolecular N_host—H...O_guest, O_guest—H...N_host, O_guest—H...O_guest and C_host—H...O_guest hydrogen bonds. It should be noted that the solvent propan-2-ol in (II) and propan-2-one in (III) show orientational disorder. The propan-2-ol molecule lies close to a twofold axis, while the propan-2-one molecule resides strictly on a twofold axis through the carbonyl C atom. In both cases, the water molecules present positional disorder of the H atoms.

A fully ordered structure is reported for the polymorph of triphenylsilanol–4,4′-bipyridyl (4/1), 4C₁₈H₁₆OSi·C₁₀H₈N₂, having Z′ = 4. The asymmetric unit contains four similar but distinct five-molecule aggregates, in which the central bipyridyl unit is linked to two molecules of triphenylsilanol via O—H...N hydrogen bonds, with a further pair of triphenylsilanol molecules linked to the first pair via O—H...O hydrogen bonds. An extensive series of C—H...π(arene) hydrogen bonds links these aggregates into complex sheets. This structure is compared with a previously reported structure [Bowes, Ferguson, Lough & Glidewell (2003). Acta Cryst. B59, 277–286], which was based on an erroneous disordered structural model arising from a false direct-methods solution with reference to a strong pseudo-inversion centre.

The title salt, C₁₈H₄₆N₂O₂Si₂²⁺·2Cl⁻, has been synthesized by reaction of N,N′-bis(2-hydroxyethyl)ethylenediamine with tert-butyldimethylsilyl chloride. The zigzag backbone dication is located across an inversion centre and the two chloride anions are related by inversion symmetry. The ionic components form a supramolecular two-dimensional network via N—H...Cl hydrogen bonding, which is responsible for the high melting point compared with the oily compound N,N′-bis[2-(tert-butyldimethylsiloxy)ethyl]ethylenediamine.

The natural title compound, C₁₁H₁₂O₄, extracted from the Chilean native tree Aristotelia chilensis (Maqui), is a polymorph of the synthetic E form reported by Xia, Hu & Rao [Acta Cryst. (2004), E60, o913–o914]. Both rotational conformers are identical from a metrical point of view, and only differ in the orientation of the 3,4-dihydroxyphenyl ring with respect to the rest of the molecule, which leads to completely different crystal structure arrangements and packing efficiencies. The reasons behind both reside in the different hydrogen-bonding interactions.

A new 1,3,4-oxadiazole-containing bispyridyl ligand, namely 5-(pyridin-4-yl)-3-[2-(pyridin-4-yl)ethyl]-1,3,4-oxadiazole-2(3H)-thione (L), has been used to create the novel complexes tetranitratobis{μ-5-(pyridin-4-yl)-3-[2-(pyridin-4-yl)ethyl]-1,3,4-oxadiazole-2(3H)-thione}zinc(II), [Zn₂(NO₃)₄(C₁₄H₁₂N₄OS)₂], (I), and catena-poly[[[dinitratocopper(II)]-bis{μ-5-(pyridin-4-yl)-3-[2-(pyridin-4-yl)ethyl]-1,3,4-oxadiazole-2(3H)-thione}] nitrate acetonitrile sesquisolvate dichloromethane sesquisolvate], {[Cu(NO₃)(C₁₄H₁₂N₄OS)₂]NO₃·1.5CH₃CN·1.5CH₂Cl₂}_n, (II). Compound (I) presents a distorted rectangular centrosymmetric Zn₂L₂ ring (dimensions 9.56 × 7.06 Å), where each Zn^II centre lies in a {ZnN₂O₄} coordination environment. These binuclear zinc metallocycles are linked into a two-dimensional network through nonclassical C—H...O hydrogen bonds. The resulting sheets lie parallel to the ac plane. Compound (II), which crystallizes as a nonmerohedral twin, is a coordination polymer with double chains of Cu^II centres linked by bridging L ligands, propagating parallel to the crystallographic a axis. The Cu^II centres adopt a distorted square-pyramidal CuN₄O coordination environment with apical O atoms. The chains in (II) are interlinked via two kinds of π–π stacking interactions along [01]. In addition, the structure of (II) contains channels parallel to the crystallographic a direction. The guest components in these channels consist of dichloromethane and acetonitrile solvent molecules and uncoordinated nitrate anions.

The structures of the Li^I and Na^I salts of 2-thiobarbituric acid (2-sulfanylidene-1-3-diazinane-4,6-dione, H₂TBA) have been studied. μ-Aqua-octaaquabis(μ-2-thiobarbiturato-κ²O:O′)bis(2-thiobarbiturato-κO)tetralithium(I) dihydrate, [Li₄(C₄H₃N₂O₂S)₄(H₂O)₉]·2H₂O, (I), crystallizes with four symmetry-independent four-coordinated Li^I cations and four independent HTBA⁻ anions. The structure contains two structurally non-equivalent Li^I cations and two non-equivalent HTBA⁻ anions (bridging and terminal). Eight of the coordinated water ligands are terminal and the ninth acts as a bridge between Li^I cations. Discrete [Li₄(HTBA)₄(H₂O)₉]·2H₂O complexes form two-dimensional layers. Neighbouring layers are connected via hydrogen-bonding interactions, resulting in a three-dimensional network. Poly[μ₂-aqua-tetraaqua(μ₄-2-thiobarbiturato-κ⁴O:O:S:S)(μ₂-thiobarbiturato-κ²O:S)disodium(I)], [Na₂(C₄H₃N₂O₂S)₂(H₂O)₅]_n, (II), crystallizes with six-coordinated Na^I cations. The octahedra are pairwise connected through edge-sharing by a water O atom and an O atom from the μ₄-HTBA⁻ ligand, and these pairs are further top-shared by the S atoms to form continuous chains along the a direction. Two independent HTBA⁻ ligands integrate the chains to give a three-dimensional network.

A new ternary dithulium hexacobalt icosastannide, Tm_2.22Co₆Sn₂₀, and a new quaternary thulium dilithium hexacobalt icosastannide, TmLi₂Co₆Sn₂₀, crystallize as disordered variants of the binary cubic Cr₂₃C₆ structure type (cF116). 48 Sn atoms occupy sites of m.m2 symmetry, 32 Sn atoms sites of .3m symmetry, 24 Co atoms sites of 4m.m symmetry, eight Li (or Tm in the case of the ternary phase) atoms sites of symmetry and four Tm atoms sites of symmetry. The environment of one Tm atom is an 18-vertex polyhedron and that of the second Tm (or Li) atom is a 16-vertex polyhedron. Tetragonal antiprismatic coordination is observed for the Co atoms. Two Sn atoms are enclosed in a heavily deformed bicapped hexagonal prism and a monocapped hexagonal prism, respectively, and the environment of the third Sn atom is a 12-vertex polyhedron. The electronic structures of both title compounds were calculated using the tight-binding linear muffin-tin orbital method in the atomic spheres approximation (TB–LMTO–ASA). Metallic bonding is dominant in these compounds, but the presence of Sn—Sn covalent dumbbells is also observed.

FT–IR spectroscopy and single-crystal X-ray structure analysis were used to characterize the discrete neutral compound diaquadioxidobis(n-valerato-κ²O,O′)uranium(VI), [UO₂(C₄H₉COO)₂(H₂O)₂], (I), and the ionic compound potassium dioxidotris(n-valerato-κ²O,O′)uranium(VI), K[UO₂(C₄H₉COO)₃], (II). The U^VI cation in neutral (I) is at a site of 2/m symmetry. Potassium salt (II) has two U centres and two K⁺ cations residing on twofold axes, while a third independent formula unit is on a general position. The ligands in both compounds were found to suffer severe disorder. The FT–IR spectroscopic results agree with the X-ray data. The composition and structure of the ionic potassium uranyl valerate are similar to those of previously reported potassium uranyl complexes with acetate, propionate and butyrate ligands. Progressive lengthening of the alkyl groups in these otherwise similar compounds was found to have an impact on their structures, including on the number of independent U and K⁺ sites, on the coordination modes of some of the K⁺ centres and on the minimum distances between U atoms. The evolution of the KUO₆ frameworks in the four homologous compounds is analysed in detail, revealing a new example of three-dimensional topological isomerism in coordination compounds of U^VI.

The title compound, [Fe₂(C₅H₅)₂(C₄₀H₂₂O₂)] or 1,4-(FcPh)₂Aq [where FcPh is 2-(4-ferrocenylphenyl)ethynyl and Aq is anthraquinone], was synthesized in an attempt to obtain a new solvent-incorporating porous material with a large void space. Thermodynamic data for 1,4-(FcPh)₂Aq show a phase transition at approximately 430 K. The crystal structure of solvent-free 1,4-(FcPh)₂Aq was determined at temperatures of 90, 300 and 500 K using synchrotron powder diffraction data. A direct-space method using a genetic algorithm was employed for structure solution. Charge densities calculated from observed structure factors by the maximum entropy method were employed for model improvement. The final models were obtained through multistage Rietveld refinements. In both phases, the structures of which differ only subtly, the planar Aq fragments are stacked alternately in opposite orientations, forming a one-dimensional column. The FcPh arms lie between the stacks and fill the remaining space, leaving no voids. C—H...π interactions between the Ph and Fc fragments mediate crystal packing and stabilization.

The title compound, C₉H₁₃N₄O₃⁺·NO₃⁻, is the first structurally characterized Schiff base derived from semicarbazide and pyridoxal. Unusually for an unsubstituted semicarbazone, the compound adopts a syn conformation, in which the carbonyl O atom is in a cis disposition relative to the azomethine N atom. This arrangement is supported by a pair of hydrogen bonds between the organic cation and the nitrate anion. The cation is essentially planar, with only a hydroxymethyl O atom deviating significantly from the mean plane of the remaining atoms (r.m.s. deviation of the remaining non-H atoms = 0.01 Å). The molecules are linked into flat layers by N—H...O and C—H...O hydrogen bonds. O—H...O hydrogen bonds involving the hydroxymethyl group as a donor interconnect the layers into a three-dimensional structure.

The organic acid–base complex 1,1,3,3-tetramethylguanidinium 4-methylbenzenesulfonate, C₅H₁₄N₃⁺·C₇H₇O₃S⁻, was obtained from the corresponding 1,1,3,3-tetramethylguanidinium 4-methylbenzenesulfinate complex, C₅H₁₄N₃⁺·C₇H₇O₂S⁻, by solid-state oxidation in air. Comparison of the two crystal structures reveals similar packing arrangements in the monoclinic space group P2₁/c, with centrosymmetric 2:2 tetramers being connected by four strong N—H...O=S hydrogen bonds between the imine N atoms of two 1,1,3,3-tetramethylguanidinium bases and the O atoms of two acid molecules.

The reaction of N¹,N^1′-(ethane-1,2-diyl)bis(propane-1,3-diamine) (bapen), K₂[Ni(CN)₄]·H₂O and dimethylformamide in the presence of Gd(NO₃)₃·6H₂O under solvothermal conditions yielded yellow crystals of dicyanido(2,3,4,6,7,9,10,11-octahydropyrimido[2′,1′:3,4]pyrazino[1,2-a]pyrimidine)nickel(II) hemihydrate, [Ni(CN)₂(C₁₀H₁₆N₄)]·0.5H₂O, (I), the crystal structure of which is composed of [Ni(CN)₂(pdpm)] molecules (pdpm is 2,3,4,6,7,9,10,11-octahydropyrimido[2′,1′:3,4]pyrazino[1,2-a]pyrimidine) on general positions linked by O—H...N hydrogen bonds to water molecules located on twofold axes. This structural unit is further linked by nonclassical C—H...N interactions to form a warped two-dimensional net perpendicular to the unit-cell b axis. The nets are stacked, with C—H...O contacts joining successive units. The Ni^II cation is coordinated with square-planar geometry by a chelating pdpm ligand and two cyanide ligands in mutually cis positions. Complex (I) is stable up to 360 K, at which point dehydration takes place; the ligands start to decompose at 558 K.

Bis[μ-di-tert-butyl(hydroxy)silanolato]bis[chloridoindium(III)], [In₂(C₈H₁₉O₂Si)₂Cl₄], (I), is a centrosymmetric two-centre indium complex featuring a system of three annulated four-membered rings; the structure is the first example of an In₂O₂ ring which is annulated with two Si—O units to form a ring system composed of three rings. The coordination environment of the In centres is a distorted trigonal bipyramid. The crystal packing of (I) is characterized by chains of molecules connected by O—H...Cl hydrogen bonds. The crystal of (I) was a nonmerohedral twin. There is no known example of an In₂O₂ ring in which the In atoms carry any two halogen ligands. The structure of tetrakis(tetrahydrofuran)lithium tetrakis[(trimethylsilyl)methyl]borate, [Li(C₄H₈O)₄](C₁₆H₄₄BSi₄), (II), is composed of discrete cations and anions. The coordination geometries of the Li and B centres is tetrahedral. The cations and anions lie in planes parallel to the ab plane. There are no short contacts between the cations and anions. Compound (II) is the first example of a B centre bonded to four –CH₂Si units.

The title compound, [K(C₁₄H₂₃)(C₄H₈O)]_n, comprises zigzag chains of alternating bridging 2,3,4,5-tetramethyl-1-n-pentylcyclopentadienyl ligands and potassium ions, with an ancillary tetrahydrofuran ligand in the coordination environment of potassium. The coordination polymer strands so formed extend by 2₁ screw symmetry in the b-axis direction. The chemically modified cyclopentadienyl ligand, with a tethered n-pentyl group, was synthesized from 2,3,4,5-tetramethylcyclopent-2-enone by a Grignard reaction.

A novel metal–organic framework, {[Zn₂Cl₄(C₂₅H₂₄N₄O₄)]·4C₃H₇NO}_n, has been synthesized solvothermally by assembling the semi-rigid tetrahedral ligand tetrakis[(pyridin-4-yl)oxymethyl]methane (tpom) and zinc nitrate in dimethylformamide (DMF). The crystal structure is noncentrosymmetric (P2₁c). Each Zn^II cation has a tetrahedral coordination environment (C₂ symmetry), which is formed by two chloride ligands and two pyridine N atoms from two tpom ligands. The tetrahedral tetradentate tpom linker has a quaternary C atom located on the crystallographic axis. This linker utilizes all the peripheral pyridine N atoms to connect four Zn^II cations, thereby forming a wave-like two-dimensional sheet along the c axis. The two-dimensional layer can be topologically simplified as a typical uninodal 4-connected sql/Shubnikov net, which is represented by the Schläfli symbol {4⁴,6²}. Adjacent layers are further packed into a three-dimensional structure by C—H...Cl hydrogen bonds.

The title compound, hexadecacarbonylbis{μ₃-[(diphenylphosphanyl)methanediidyl]sulfanido}-μ₄-disulfido(2−)-hexairon(4 Fe—Fe), [Fe₆(C₁₃H₁₀PS)₂(S₂)(CO)₁₆], contains two inversion-related [Fe₃(Ph₂PCS)(CO)₈] subclusters linked by an equatorial disulfide bond [S—S = 2.1490 (9) Å]. Each Ph₂PCS³⁻ ligand is coordinated to a triiron core in a μ₃-κP:κ²C:κ²S fashion.

The title complex, [Rh(C₁₀H₁₅)Cl(C₁₄H₁₂N₂O₄)]Cl·2C₄H₅NO₃, has been synthesized by a substitution reaction of the precursor [bis(2,5-dioxopyrrolidin-1-yl) 2,2′-bipyridine-4,4′-dicarboxylate]chlorido(pentamethylcyclopentadienyl)rhodium(III) chloride with NaOCH₃. The Rh^III cation is located in an RhC₅N₂Cl eight-coordinated environment. In the crystal, 1-hydroxypyrrolidine-2,5-dione (NHS) solvent molecules form strong hydrogen bonds with the Cl⁻ counter-anions in the lattice and weak hydrogen bonds with the pentamethylcyclopentadienyl (Cp*) ligands. Hydrogen bonding between the Cp* ligands, the NHS solvent molecules and the Cl⁻ counter-anions form links in a V-shaped chain of Rh^III complex cations along the c axis. Weak hydrogen bonds between the dimethyl 2,2′-bipyridine-4,4′-dicarboxylate ligands and the Cl⁻ counter-anions connect the components into a supramolecular three-dimensional network. The synthetic route to the dimethyl 2,2′-bipyridine-4,4′-dicarboxylate-containing rhodium complex from the [bis(2,5-dioxopyrrolidin-1-yl) 2,2′-bipyridine-4,4′-dicarboxylate]rhodium(III) precursor may be applied to link Rh catalysts to the surface of electrodes.

Two polyoxometallate-based compounds, tris[1,1′-(butane-1,4-diyl)bis(1H-imidazol-3-ium)] bis[tetracosa-μ₂-oxido-dodecaoxido-μ₁₂-phosphato-dodecamolybdenum(VI)], (C₁₀H₁₆N₄)₃[PMo₁₂O₄₀]₂, (I), and 1,1′-(butane-1,4-diyl)bis(1H-imidazol-3-ium) 1-[4-(1H-imidazol-1-yl)butyl]-1H-imidazol-3-ium tetracosa-μ₂-oxido-dodecaoxido-μ₁₂-phosphato-dodecamolybdenum(VI) dihydrate, (C₁₀H₁₆N₄)(C₁₀H₁₅N₄)[PMo₁₂O₄₀]·2H₂O, (II), were synthesized by hydrothermal techniques at different pH values. The stoichiometric ratio between the polyoxometallate (POM) anions and organic cations is 2:3 in (I), with one of the cations lying on an inversion centre. The doubly protonated 1,1′-(butane-1,4-diyl)diimidazole (BIM) cations are linked to the [PMo₁₂O₄₀]³⁻ anions by hydrogen bonds to form a three-dimensional supramolecular network. The stoichiometric ratio of POM anions and organic cations is 1:2 in (II), and the anion is located about a centre of inversion. The partly protonated BIM cations and solvent water molecules form hydrogen bonds with the [PMo₁₂O₄₀]³⁻ anions, yielding a two-dimensional supramolecular layer. The different lattice architectures of (I) and (II) may be governed by the ratio between the POM anions and organic cations, which, in turn, is determined by the pH value.

In the title compound, {[Cu(C₁₅H₁₁ClN₂O₃)(C₄H₉NO)]_n, the Cu^II cation has square-pyramidal geometry. The morpholine ligand serves as a bridge to link two symmetry-related metal atoms, resulting in an infinite chain structure along the a axis. Adjacent chains are extended into a two-dimensional layered structure via hydrogen bonds formed between morpholine and amide N atoms [N—H...N = 2.971 (3) Å].

In the title mixed-ligand metal–organic polymeric complex, {[Co(NCS)₂(C₈H₁₂N₆)₂]·2H₂O}_n, the asymmetric unit contains a divalent Co^II cation, which sits on an inversion centre, two halves of two crystallographically distinct and centrosymmetric 1,4-bis(1,2,4-triazol-1-yl)butane (BTB) ligands, one N-bound thiocyanate ligand and one solvent water molecule. The Co^II atom possesses a distorted {CoN₆} octahedral geometry, with the equatorial positions taken up by triazole N atoms from four different BTB ligands. The axial positions are filled by thiocyanate N atoms. In the crystal, each Co^II atom is linked covalently to four others through the distal donors of the tethering BTB ligands, forming a neutral (4,4)-topology two-dimensional rhomboid grid layer motif, which is coincident with the (11) crystal planes. Magnetic investigations show that weak antiferromagnetic coupling exists between Co^II atoms in the complex.

Two new symmetric double-armed oxadiazole-bridged ligands, 4-methyl-{5-[5-methyl-2-(pyridin-3-ylcarbonyloxy)phenyl]-1,3,4-oxadiazol-2-yl}phenyl pyridine-3-carboxylate (L1) and 4-methyl-{5-[5-methyl-2-(pyridin-4-ylcarbonyloxy)phenyl]-1,3,4-oxadiazol-2-yl}phenyl pyridine-4-carboxylate (L2), were prepared by the reaction of 2,5-bis(2-hydroxy-5-methylphenyl)-1,3,4-oxadiazole with nicotinoyl chloride and isonicotinoyl chloride, respectively. Ligand L1 can be used as an organic clip to bind Cu^II cations and generate a molecular complex, bis(4-methyl-{5-[5-methyl-2-(pyridin-3-ylcarbonyloxy)phenyl]-1,3,4-oxadiazol-2-yl}phenyl pyridine-3-carboxylate)bis(perchlorato)copper(II), [Cu(ClO₄)₂(C₂₈H₂₀N₄O₅)₂], (I). In compound (I), the Cu^II cation is located on an inversion centre and is hexacoordinated in a distorted octahedral geometry, with the pyridine N atoms of two L1 ligands in the equatorial positions and two weakly coordinating perchlorate counter-ions in the axial positions. The two arms of the L1 ligands bend inward and converge at the Cu^II coordination point to give rise to a spirometallocycle. Ligand L2 binds Cu^I cations to generate a supramolecule, diacetonitriledi-μ₃-iodido-di-μ₂-iodido-bis(4-methyl-{5-[5-methyl-2-(pyridin-4-ylcarbonyloxy)phenyl]-1,3,4-oxadiazol-2-yl}phenyl pyridine-4-carboxylate)tetracopper(I), [Cu₄I₄(CH₃CN)₂(C₂₈H₂₀N₄O₅)₂], (II). The asymmetric unit of (II) indicates that it contains two Cu^I atoms, one L2 ligand, one acetonitrile ligand and two iodide ligands. Both of the Cu^I atoms are four-coordinated in an approximately tetrahedral environment. The molecule is centrosymmetric and the four I atoms and four Cu^I atoms form a rope-ladder-type [Cu₄I₄] unit. Discrete units are linked into one-dimensional chains through π–π interactions.

In the title complex, [Cu(C₁₆H₁₆Cl₃N₃O₂P)Cl(C₁₂H₈N₂)], the Cu^II cation presents a square-pyramidal environment, where the CuO₂N₂ base is formed by two O atoms from carbonyl and phosphoryl groups, and by two N atoms from a 1,10-phenanthroline molecule. A coordinated Cl atom occupies the apex. N—H...Cl hydrogen bonds link the molecules into one-dimensional chains. The trichloromethyl group is rotationally disordered over two positions, with occupancies of 0.747 (7) and 0.253 (7).

The cation-templated self-assembly of 1,4-bis(2-methyl-1H-imidazol-1-yl)butane (bmimb) with CuSCN gives rise to a novel two-dimensional network, namely catena-poly[2,2′-dimethyl-1,1′-(butane-1,4-diyl)bis(1H-imidazol-3-ium) [tetra-μ₂-thiocyanato-κ⁴S:S;κ⁴S:N-dicopper(I)]], {(C₁₂H₂₀N₄)[Cu₂(NCS)₄]}_n. The Cu^I cation is four-coordinated by one N and three S atoms, giving a tetrahedral geometry. One of the two crystallographically independent SCN⁻ anions acts as a μ₂-S:S bridge, binding a pair of Cu^I cations into a centrosymmetric [Cu₂(NCS)₂] subunit, which is further extended into a two-dimensional 4⁴-sql net by another kind of SCN⁻ anion with an end-to-end μ₂-S:N coordination mode. Interestingly, each H₂bmimb dication, lying on an inversion centre, threads through one of the windows of the two-dimensional 4⁴-sql net, giving a pseudorotaxane-like structure. The two-dimensional 4⁴-sql networks are packed into the resultant three-dimensional supramolecular framework through bmimb–SCN N—H...N hydrogen bonds.

The title compound, [Cu₈(C₁₅H₁₀N₃O₃S)₄Cl₄(C₃H₇NO)₂]·2C₃H₇NO, consisting of eight Cu^II cations, four trianionic 1-(2-oxidobenzoyl)-2-(2-oxo-2-phenylethanethioyl)hydrazine-1,2-diide ligands, four chloride ligands and two coordinated and two solvent dimethylformamide molecules, crystallizes with the octanuclear molecule located on an inversion centre. The two halves of the molecule are connected by two bridging Cl atoms. This is the first example of an octanuclear complex based on a thiosemicarbazone-derived ligand.

A new metal–formate framework, poly[1H-imidazol-3-ium [tri-μ₂-formato-manganese(II)]], {(C₃H₅N₂)[Mn(HCOO)₃]}_n, was synthesized and its structural phase transition was studied by thermal analysis and variable-temperature X-ray diffraction analysis. The transition temperature is around 435 K. The high-temperature phase is tetragonal and the low-temperature phase is monoclinic, with a β angle close to 90°. The relationship of the unit cells between the two phases can be described as: a_HT = 0.5a_LT + 0.5b_LT; b_HT = −0.5a_LT + 0.5b_LT; c_HT = 0.5c_LT. In the high-temperature phase, both the framework and the guest 1H-imidazol-3-ium (HIm) cations are disordered; the HIm cations are located about 2mm sites and were modelled as fourfold disordered. The Mn and a formate C atom are located on fourfold rotary inversion axes, while another formate C atom is on a mirror plane. The low-temperature structure is ordered and consists of two crystallographically independent HIm cations and two crystallographically independent Mn²⁺ ions. The phase transition is attributable to the order–disorder transition of the HIm cations.

In the crystal structure of the title two-dimensional metal–organic polymeric complex, [Cd₂Cl₄(C₈H₁₄N₂O₄)(H₂O)₂]_n, the asymmetric unit contains a crystallographically independent Cd^II cation, two chloride ligands, an aqua ligand and half a 2,2′-(piperazine-1,4-diium-1,4-diyl)diacetate (H₂PDA) ligand, the piperazine ring centroid of which is located on a crystallographic inversion centre. Each Cd^II centre is six-coordinated in an octahedral environment by an O atom from an H₂PDA ligand and an O atom from an aqua ligand in a trans disposition, and by four chloride ligands arranged in the plane perpendicular to the O—Cd—O axis. The complex forms a two-dimensional layer polymer containing [CdCl₂]_n chains, which are interconnected into an extensive three-dimensional hydrogen-bonded network by C—H...O, C—H...Cl and O—H...O hydrogen bonds.

The title compound, [CuBr(C₆H₇NO)₂]Br·H₂O, is an ionic mononuclear complex in which the [CuBr(C₆H₇NO)₂]⁺ cation possesses distorted square-pyramidal geometry. The Cu^II centre is coordinated by two neutral 2-(pyridin-2-yl)methanol (2-pyMeOH) ligands and a terminal bromide ligand. The 2-pyMeOH ligands are coordinated in a bidentate chelating manner through the pyridine N and hydroxy O atoms, forming a five-membered chelate ring with the Cu^II centre. The planes of the pyridine rings are twisted by 58.71 (14)° with respect to each other. The charge is balanced by a noncoordinating bromide anion which, together with a solvent water molecule, links the components through hydrogen bonds into infinite chains propagating along the a axis. The mononuclear cations appear to associate in pairs through weak interactions between the metal atom of one cation and the halogen atom of an adjacent cation.

The title compound, C₈H₁₂Br₄, displays crystallographic inversion symmetry, so that the cyclobutane ring is exactly planar. The ring C—C bond with eclipsed substituents is lengthened somewhat to 1.572 (5) Å. The packing can be described in terms of three Br...Br contacts; two of these combine to form layers of molecules parallel to the ac plane, while the third crosslinks the layers in the third dimension. A simple topological descriptor for systems involving Br...Br contacts is proposed.

Low-temperature X-ray diffraction experiments were employed to investigate the crystal structures of an orthorhombic polymorph of the intramolecular cyclization product of perindopril, a popular angiotensive-converting enzyme (ACE) inhibitor, namely ethyl (2S)-2-[(3S,5aS,9aS,10aS)-3-methyl-1,4-dioxo-5a,6,7,8,9,9a,10,10a-octahydro-3H-pyrazino[1,2-a]indol-2-yl]pentanoate, C₁₉H₃₀N₂O₄, (Io), and its tetragonal equivalent, (It), which was previously reported at ambient temperature [Bojarska et al. (2013). J. Chil. Chem. Soc.58, 1415–1417]. Polymorph (Io) crystallizes in the orthorhombic space group P2₁2₁2₁ with two molecules in the asymmetric unit, while tetragonal form (It) crystallizes in the space group P4₁2₁2 with one molecule in the asymmetric unit. The geometric parameters of (Io) are very similar to those of (It). The six-membered rings in both polymorphs adopt a slightly deformed chair conformation and the piperazinedione rings are in a boat conformation. However, the proline rings adopt an envelope conformation in (Io), while in (It) the ring exists in a slightly deformed half-chair conformation. The most significant difference between the two structures is the orientation of the ethyl pentanoate chain. Molecules associate in pairs in a head-to-tail manner forming infinite columns. In (Io), molecules are related by a twofold screw axis forming identical columns, while in (It), molecules in successive neighbouring columns are related by alternating twofold screw axes and fourfold screw axes. In both cases, the crystal packing is stabilized by weak intermolecular C—H...O interactions only.

The title compound, C₅₈H₆₄S₈, has been prepared by Pd-catalysed direct C—H arylation of tetrathienonaphthalene (TTN) with 5-hexyl-2-iodothiophene and recrystallized by slow evaporation from dichloromethane. The crystal structure shows a completely planar geometry of the TTN core, crystallizing in the monoclinic space group P2₁/c. The structure consists of slipped π-stacks and the interfacial distance between the mean planes of the TTN cores is 3.456 (5) Å, which is slightly larger than that of the comparable derivative of tetrathienoanthracene (TTA) with 2-hexylthiophene groups. The packing in the two structures is greatly influenced by both the aromatic core of the structure and the alkyl side chains.

The crystal structures of 3,4,6a,7,10,10a-hexahydro-7,10-epoxypyrimido[2,1-a]isoindol-6(2H)-one, C₁₁H₁₂N₂O₂, and 2-(2-aminoethyl)-3a,4,7,7a-tetrahydro-1H-4,7-epoxyisoindole-1,3(2H)-dione, C₁₀H₁₂N₂O₃, two tricyclic imides, show one and two molecules in the asymmetric unit, respectively. Intermolecular hydrogen-bonding interactions are observed in both compounds.

The three pyran structures 6-methylamino-5-nitro-2,4-diphenyl-4H-pyran-3-carbonitrile, C₁₉H₁₅N₃O₃, (I), 4-(3-fluorophenyl)-6-methylamino-5-nitro-2-phenyl-4H-pyran-3-carbonitrile, C₁₉H₁₄FN₃O₃, (II), and 4-(4-chlorophenyl)-6-methylamino-5-nitro-2-phenyl-4H-pyran-3-carbonitrile, C₁₉H₁₄ClN₃O₃, (III), differ in the nature of the aryl group at the 4-position. The heterocyclic ring in all three structures adopts a flattened boat conformation. The dihedral angle between the pseudo-axial phenyl substituent and the flat part of the pyran ring is 89.97 (1)° in (I), 80.11 (1)° in (II) and 87.77 (1)° in (III). In all three crystal structures, a strong intramolecular N—H...O hydrogen bond links the flat conjugated H—N—C=C—N—O fragment into a six-membered ring. In (II), molecules are linked into dimeric aggregates by N—H... O(nitro) hydrogen bonds, generating an R₂²(12) graph-set motif. In (III), intermolecular N—H...N and C—H...N hydrogen bonds link the molecules into a linear chain pattern generating C(8) and C(9) graph-set motifs, respectively.

(2S,3S)-2,6-Dimethylheptane-1,3-diol, C₉H₂₀O₂, (I), was synthesized from the ketone (R)-4-benzyl-3-[(2R,3S)-3-hydroxy-2,6-dimethylheptanoyl]-1,3-oxazolidin-2-one, C₁₉H₂₇NO₄, (II), containing C atoms of known chirality. In both structures, strong hydrogen bonds between the hydroxy groups form tape motifs. The contribution from weaker C—H...O hydrogen bonds is much more evident in the structure of (II), which furthermore contains an example of a direct short Osp³...Csp² contact that represents a usually unrecognized type of intermolecular interaction.

The core of the novel title centrosymmetric porphyrin derivative, C₇₂H₈₆N₄O₄, with long flexible hexyloxy substituents, is almost planar, which is anticipated to facilitate π-electron delocalization and lead to a significant deviation between the planes of the benzene rings and the molecular plane. The two N-bound H atoms on the pyrrole rings are disordered and the occupancy factors refined to a ratio of 0.28 (2):0.72 (2).

Levulinic acid derivatives are potential `green chemistry' renewably sourced molecules with utility in industrial coatings applications. Suitable single crystals of the centrosymmetric title compounds, C₁₄H₂₂O₆ and C₁₆H₂₆O₆, respectively, were obtained with difficulty. The data for the latter hexane-1,6-diyl compound were extracted from the major fragment of a three-component twinned crystal. Both compounds crystallize in similar-sized unit cells with identical symmetry, utilizing the same weak nonconventional attractive C—H...O(ketone) hydrogen bonds via C(4) and C(5) motifs, which expand to R²₂(30) ring and C²₂(14) chain motifs. Their different packing orientations in similar-sized unit cells suggest that crystal growth involving packing mixes could lead to intergrowths or twins.

Reaction between cysteamine (systematic name: 2-aminoethanethiol, C₂H₇NS) and L-(+)-tartaric acid [systematic name: (2R,3R)-2,3-dihydroxybutanedioic acid, C₄H₆O₆] results in a mixture of cysteamine tartrate(1−) monohydrate, C₂H₈NS⁺·C₄H₅O₆⁻·H₂O, (I), and cystamine bis[tartrate(1−)] dihydrate, C₄H₁₄N₂S₂²⁺·2C₄H₅O₆⁻·2H₂O, (III). Cystamine [systematic name: 2,2′-dithiobis(ethylamine), C₄H₁₂N₂S₂], reacts with L-(+)-tartaric acid to produce a mixture of cystamine tartrate(2−), C₄H₁₄N₂S₂²⁺·C₄H₄O₆²⁻, (II), and (III). In each crystal structure, the anions are linked by O—H...O hydrogen bonds that run parallel to the a axis. In addition, hydrogen bonding involving protonated amino groups in all three salts, and water molecules in (I) and (III), leads to extensive three-dimensional hydrogen-bonding networks. All three salts crystallize in the orthorhombic space group P2₁2₁2₁.

In the crystal structure of 6-methoxyquinoline N-oxide dihydrate, C₁₀H₉NO₂·2H₂O, (I), the presence of two-dimensional water networks is analysed. The water molecules form unusual water channels, as well as two intersecting mutually perpendicular columns. In one of these channels, the O atom of the N-oxide group acts as a bridge between the water molecules. The other channel is formed exclusively by water molecules. Confirmation of the molecular packing was performed through the analysis of Hirshfeld surfaces, and (I) is compared with other similar isoquinoline systems. Calculations of bond lengths and angles by the Hartree–Fock method or by density functional theory B3LYP, both with 6-311++G(d,p) basis sets, are reported, together with the results of additional IR, UV–Vis and theoretical studies.

The title compound, C₁₆H₉FN₂S, crystallizes as a nonmerohedral twin with twin rotation about the reciprocal-lattice vector [10]*. The molecules are nearly planar and the dihedral angle between the planes of the two aryl rings is only 4.4 (2)°. The molecules are linked by pairs of C—H...N hydrogen bonds to form cyclic centrosymmetric R₂²(18) dimers, which are linked into chains by an aromatic π–π stacking interaction. Comparisons are made with some related 3-aryl-2-thienylacrylonitriles.

The crystal structure of the free base of the antidiabetic drug alogliptin [systematic name: 2-({6-[(3R)-3-aminopiperidin-1-yl]-3-methyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-1-yl}methyl)benzonitrile], C₁₈H₂₁N₅O₂, displays a two-dimensional N—H...O hydrogen-bonded network. It contains two independent molecules, which have the same conformation but differ in their hydrogen-bond connectivity. In the crystal structure of the benzoate salt (systematic name: (3R)-1-{3-[(2-cyanophenyl)methyl]-1-methyl-2,6-dioxo-1,2,3,6-tetrahydropyrimidin-4-yl}piperidin-3-aminium benzoate), C₁₈H₂₂N₅O₂⁺·C₇H₅O₂⁻, the NH₃⁺ group of the cation is engaged in three intermolecular N—H...O hydrogen bonds to yield a hydrogen-bonded layer structure. The benzoate salt and the free base differ fundamentally in the conformations of their alogliptin moieties.

The title compound, C₅₉H₅₆ClN₃O₁₆, is an important dissacharide precursor to novel therapeutics for the treatment of Alzheimer's disease. It crystallizes with two independent enantiomerically identical molecules in almost exactly the same orientation in the cell, being one half cell-edge apart. Apart from the conformation of a single benzyl group, the molecules are superimposable. They are bound efficiently using complementary C—H...O(carbonyl) hydrogen bonds, principally along the `duplicating' axis. The absolute configurations were determined.