2‐Amino­pyridinium–fumarate–fumaric acid (2/1/1)

The title complex, 2C₅H₇N₂⁺·C₄H₂O₄²⁻·C₄H₄O₄, contains cyclic eight‐membered hydrogen‐bonded rings involving 2‐­aminopyridinium and fumarate ions. The fumaric acid mol­ecules and fumarate ions lie on inversion centers and are linked into zigzag chains by O—H⋯O hydrogen bonds. The dihedral angle between the pyridinium ring and the hydrogen‐bonded fumarate ion is 7.60 (4)°. The fumarate anion is linked to the pyridinium cations by intermolecular N—H⋯O hydrogen bonds. The heterocycle is fully protonated, thus enabling amine–imine tautomerization.     

Berberine formate–succinic acid (1/1)

The title compound [systematic name: 9,10‐di­methoxy‐2,3‐methyl­ene­dioxy‐5,6‐di­hydro­dibenzo­[a,g]­quinolizinium form­ate–succinic acid (1/1)], C₂₀H₁₈NO₄⁺·CHO₂⁻·C₄H₆O₄, con­tains centrosymmetric pairs of almost planar berberine cations, and hydrogen‐bonded (C₄H₆O₄⋯HCOO⁻)₂ rings of succinic acid with formate anions, bonded by O—H⋯O hydrogen bonds with O⋯O distances of 2.4886 (15) and 2.5652 (16) Å. Pairs of cations and mol­ecules of succinic acid are connected by non‐conventional weak C—H⋯O hydrogen bonds, with C⋯O distances of 3.082 (2) and 3.178 (2) Å.     

Piperazine‐1,4‐diium–2,4‐dinitrophenolate–water (1/2/2)

In the title 1/2/2 adduct, C₄H₁₂N₂²⁺·2C₆H₃N₂O₅^?·2H₂O, the dication lies on a crystallographic inversion centre and the asymmetric unit also has one anion and one water mol­ecule in general positions. The 2,4‐di­nitro­phenolate anions and the water mol­ecules are linked by two O—H?O and two C—H?O hydrogen bonds to form molecular ribbons, which extend along the b direction. The piperazine dication acts as a donor for bifurcated N—H?O hydrogen bonds with the phenolate O atom and with the O atom of the o‐nitro group. Six symmetry‐related molecular ribbons are linked to a piperazine dication by N—H?O and C—H?O hydrogen bonds.     

The ternary complex 4‐(2‐pyridyl)pyridinium–3,5‐di­nitro­benzoate–3,5‐di­nitro­benzoic acid (1/1/1)

In the title ternary complex, C₁₀H₉N₂⁺·C₇H₃N₂O₆^?·C₇H₄N₂O₆, the pyridinium cation adopts the role of the donor in an intermolecular N—H?O hydrogen‐bonding interaction with the carboxyl­ate group of the 3,5‐di­nitro­benzoate anion. The mol­ecules of the ternary complex form molecular ribbons perpendicular to the b direction, which are stabilized by one N—H?O, one O—H?O and five C—H?O intermolecular hydrogen bonds. The ribbons are further interconnected by three intermolecular C—H?O hydrogen bonds into a three‐dimensional network.     

Hexa­methyl­enetetra­mine–4‐nitro­catechol–water (1/2/1)

In the title adduct, 1,3,5,7‐tetra­aza­tri­cyclo[3.3.1.1^3,7]dec­ane–4‐nitro­benzene‐1,2‐diol–water (1/2/1), C₆H₁₂N₄·2C₆H₅NO₄·H₂O, the hexa­methyl­ene­tetra­mine mol­ecule acts as an acceptor of intermolecular O—H?N hydrogen‐bonding interactions from the water mol­ecule and the hydroxy groups of one of the two symmetry‐independent 4‐nitro­catechol mol­ecules. The structure is built from molecular layers which are stabilized by three intermolecular O—H?O, two intermolecular O—H?N and four intermolecular C—H?O hydrogen bonds. The layers are further interconnected by one additional intermolecular O—H?N and two intermolecular C—H?O hydrogen bonds.     

The 2:1 complex of maleic acid and 1,4‐diazabicyclo[2.2.2]octane: hydrogen‐bonded sheets linked by C–H⋯O hydrogen bonds

In the title complex, 1,4‐diazo­niabi­cyclo­[2.2.2]­octane bis­(hy­drogen maleate), C₆H₁₄N₂²⁺·2C₄H₃O₄^?, the C₄H₃O₄^? and C₆H₁₄N₂²⁺ ions, derived from maleic acid and 1,4‐di­aza­bi­cyclo­[2.2.2]­octane, respectively, are disordered across a mirror plane in space group Cmc2₁, and they are linked by two nearly linear N—H?O hydrogen bonds, with N?O distances of 2.662 (3) and 2.614 (4) Å, and N—H?O angles of 173°. The crystal structure consists of sheets with reticulations of 3.3792 (4) Å in stratum and 7.3892 (8) Å in width. The sheets are linked by C—H?O hydrogen bonds.     

Moxifloxacinium chloride–water–methanol (2/1/1), a novel anti­bacterial agent

Moxifloxacin, a novel fluoro­quinolone with a broad spectrum of anti­bacterial activity, is available as the solvated monohydro­chloride salt 7‐[(S,S)‐2‐aza‐8‐azoniabicyclo­[4.3.0]non‐8‐yl]‐1‐cyclo­propyl‐6‐fluoro‐8‐meth­oxy‐4‐oxo‐1,4‐dihydroquinoline‐3‐carboxylic acid chloride–water–methanol (2/1/1), C₂₁H₂₅FN₃O₄⁺·Cl⁻·0.5H₂O·0.5CH₃OH. The asymmetric unit contains two cations, two chloride ions, a mol­ecule of water and one methanol mol­ecule. The two cations adopt conformations that differ by an almost 180° rotation with respect to the piperidinopyrrolidine side chain. The cyclo­propyl ring and the meth­oxy group are not coplanar with the quinoline ring system. The carboxylic acid function, the protonated terminal piperidyl N atom, the water mol­ecule, the chloride ion and the methanol mol­ecule participate in O—H⋯O, O—H⋯Cl, N—H⋯O and N—H⋯Cl hydrogen bonding, linking the mol­ecules into extended two‐dimensional networks.     

The 1:1 adduct of Kemp's triacid with 2‐aminopyridine

The crystal structure determination of the molecular proton‐transfer adduct of Kemp's triacid (cis‐cis‐1,3,5‐tri­methyl­cyclo­hexane‐1,3,5‐tri­carboxylic acid, KTA) with 2‐amino­pyridine (2‐APY), namely 2‐amino­pyridinium 3,5‐di­carboxy‐1,3,5‐tri­methyl­cyclo­hexane­carboxyl­ate, 2‐APY⁺·KTA^? or C₅H₇N₂⁺·C₁₂H₁₇O₆^?, has revealed a centrosymmetric hydrogen‐bonded cyclic KTA homodimer repeating unit [O?O 2.524 (4) Å] linked into a polymer structure through the pyridinium and amino groups of the 2‐APY mol­ecule [O?N 2.736 (4), 2.989 (4) and 2.999 (4) Å].     

2‐Pyridone–tartronic acid (1/1), 3‐hydroxy­pyridinium hydrogen tartronate and 4‐hydroxy­pyridinium hydrogen tartronate

Tartronic acid forms a hydrogen‐bonded complex, C₅H₅NO·C₃H₄O₅, (I), with 2‐pyridone, while it forms acid salts, namely 3‐hydroxy­pyridinium hydrogen tartronate, (II), and 4‐hy­droxy­pyridinium hydrogen tartronate, (III), both C₅H₆NO⁺·C₃H₃O₅⁻, with 3‐hydroxy­pyridine and 4‐hydroxy­pyridine, respectively. In (I), the pyridone mol­ecules and the acid mol­ecules form R(8) and R(10) hydrogen‐bonded rings, respectively, around the inversion centres. In (II) and (III), the cations and anions are linked by N—H⋯O and O—H⋯O hydrogen bonds to form a hydrogen‐bonded chain. In each of (I), (II) and (III), an intermolecular hydrogen bond is formed between a carboxyl group and the hydroxyl group attached to the central C atom, and in (I), the hydroxyl group participates in an intramolecular hydrogen bond with a carbonyl group. No intermolecular hydrogen bond is formed between the carboxyl groups in (I), or between the carboxyl and carboxyl­ate groups in (II) and (III).     

Benzene‐1,2,4,5‐tetra­carboxyl­ic acid–trans‐cinnam­amide (1/2)

In the title adduct, C₁₀H₆O₈·2C₉H₉NO, benzene‐1,2,4,5‐tetra­car­box­ylic acid has a crystallographic twofold axis parallel to b and forms a flat zigzag chain along c linked by O— H?O cyclic hydrogen bonds with cinnam­amide mol­ecules.     

Ethyl­ammonium and diethyl­ammonium salts of chloranilic acid

In the crystals of two title salts of chloranilic acid (2,5‐di­chloro‐3,6‐di­hydroxy‐p‐benzo­quinone), namely ethyl­ammonium chloranilate, C₂H₈N⁺·C₆HCl₂O₄^?, (I), and diethyl­ammonium chloranilate, C₄H₁₂N⁺·C₆HCl₂O₄^?, (II), the chloranilate ions are present as a hydrogen‐bonded dimer which has an inversion center. The ethyl­ammonium and diethyl­ammonium ions link the dimers through N—H?O hydrogen bonds, forming a three‐dimensional hydrogen‐bond network in (I) and a one‐dimensional chain in (II).     

Threefold interweaving of (4,4) nets built from R(58) rings in the hydrogen‐bonded adduct 1,4‐diaza­bicyclo[2.2.2]octane–5‐hydroxy­isophthalic acid (1/1)

The 1:1 adduct of 1,4‐di­aza­bi­cyclo­[2.2.2]­octane and 5‐hydroxy­isophthalic acid is a salt, [H(C₆H₁₂N₂)]⁺·­[HOC₆H₃(COOH)COO]^? or C₆H₁₃N₂⁺·C₈H₅O₅^?. The ions are linked by three types of hydrogen bond, i.e. N—H?O, O—H?O and O—H?N, into continuous two‐dimensional (4,4) nets built from a single type of R(58) ring. Six independent sheets of this type make up the structure and these are interwoven in sets of three.     

Leurosine me­thio­dide–methanol–water (1/3/2)

The crystal structure of a methanol–water solvate ofleurosine me­thio­dide, (leurosine‐CH₃)⁺I^?·3CH₃OH·2H₂O (C₄₇H₅₉IN₄O₉·3CH₃OH·2H₂O), is described. The piperidine ring of the upper part of the mol­ecule adopts a sofa conformation. An intramolecular hydrogen bond between the tertiary N and the hydroxyl group of the vindoline moiety of the mol­ecule is present.     

4‐Pyridone–terephthalic acid–water (2/1/2) and bis(3‐hydroxypyridinium) terephthalate

4‐Hydroxypyridine and terephthalic acid cocrystallize as a hydrate, 4‐pyridone–terephthalic acid–water (2/1/2), 2C₅H₅NO·C₈H₆O₄·2H₂O, from a methanol–water solution. The molecules form a two‐dimensional hydrogen‐bonded network resulting in sheets of hydrogen‐bonded molecules that lie parallel to the (10) plane. In contrast, 3‐hydroxypyridine and terephthalic acid form the salt bis(3‐hydroxypyridinium) terephthalate, 2C₅H₆NO⁺·C₈H₄O₄²⁻, giving rise to two‐dimensional hydrogen‐bonded sheets extending through the lattice parallel to the (10) plane.     

Self‐assembled hydrogen‐bonded bilayers in 1,4‐diazabicyclo[2.2.2]octane–N‐(phosphonomethyl)iminodiacetic acid–water (1/1/1.5)

The title compound is a hydrated salt, 1,4‐diazo­nia­bi­cyclo­[2.2.2]­octane–N‐[(hydroxy­phosphinato)­methyl]­iminiodi­acetate–water (1/1/1.5), C₆H₁₄N₂²⁺·C₅H₈NO₇P^2?·1.5H₂O, in which one of the water mol­ecules lies across a twofold rotation axis in space group P2/n. The ionic components are linked into sheets by a combination of a three‐centre N—H?(O)₂ hydrogen bond and two‐centre O—H?O and N—H?O hydrogen bonds, and these sheets are pairwise linked by the water mol­ecules into bilayers, by means of further O—H?O hydrogen bonds.     

Two succinic acid derivatives of 2‐ethyl‐6‐methylpyridin‐3‐ol

Crystals of bis(2‐ethyl‐3‐hydroxy‐6‐methylpyridinium) succinate–succinic acid (1/1), C₈H₁₂NO⁺·0.5C₄H₄O₄²⁻·0.5C₄H₆O₄, (I), and 2‐ethyl‐3‐hydroxy‐6‐methylpyridinium hydrogen succinate, C₈H₁₂NO⁺·C₄H₅O₄⁻, (II), were obtained by reaction of 2‐ethyl‐6‐methylpyridin‐3‐ol with succinic acid. The succinate anion and succinic acid molecule in (I) are located about centres of inversion. Intermolecular O—H...O, N—H...O and C—H...O hydrogen bonds are responsible for the formation of a three‐dimensional network in the crystal structure of (I) and a two‐dimensional network in the crystal structure of (II). Both structures are additionally stabilized by π–π interactions between symmetry‐related pyridine rings, forming a rod‐like cationic arrangement for (I) and cationic dimers for (II).     

A cyano‐bridged dinuclear 4f–3d array

A cyano‐bridged bimetallic 4f–3d complex, tri­aqua‐1κ³O‐μ‐cyano‐1:2κ²N:C‐penta­cyano‐2κ⁵C‐tetrakis(2‐pyrrolidone‐1κO)­chromium(III)­dysprosium(III) dihydrate, [CrDy(C₄H₇NO)₄(CN)₆(H₂O)₃]·2H₂O, has been prepared and characterized by X‐ray crystallographic analysis. The structure consists of a neutral cyano‐bridged Dy–Cr dimer. A hydrogen‐bonded three‐dimensional architecture is formed through N—H?O, O—H?N and O—H?O hydrogen bonds.     

1:2 Complexes of chloranilic acid with pyrazole and imidazole,and the aceto­nitrile solvate of a 1:1 complex with imidazole

2,5‐Di­chloro‐3,6‐di­hydroxy‐1,4‐benzo­quinone (chloranilic acid) forms X—H?Y (X, Y = N or O) and C—H?Cl hydrogen bonds with pyrazole and imidazole to afford bis­(pyrazolium) di­chloro­anilate and bis­(imidazolium) di­chloro­anilate, (I) and (II), both 2C₃H₅N₂⁺·C₆Cl₂O₄^2?, and imidazolium chloro­anilate aceto­nitrile solvate, C₃H₅N₂⁺·­C₆HCl₂O₄^?·C₂H₃N, (III). Their crystal structures demonstrate three novel supramolecular architectures based on supramolecular synthons to build a ladder, (I), a two‐dimensional network, (II), and a flat ribbon, (III).     

Hydro­gen bonding in calcium–tri­fluoro­methane­sulfonate–1,3‐di‐4‐pyridyl­urea–methanol (1/2/2/4)

The structure of the supramolecular complex calcium–tri­fluoro­methane­sulfonate–1,3‐di‐4‐pyridyl­urea–methanol (1/2/2/4), Ca²⁺·2CF₃SO₃⁻·2C₁₁H₁₀N₄O·4CH₄O, is presented. The Ca²⁺ ion lies on an inversion centre and is octahedrally coordinated by four methanol mol­ecules and two tri­fluoro­methane­sulfonate counter‐ions. The molecular packing is dominated by hydrogen‐bonded sheets in the (110) plane which contain R(32) rings; in these rings, significant π–π interactions are observed between inversion‐related 1,3‐di‐4‐pyridyl­urea mol­ecules.     

Multicentre hydrogen bonds in a 2:1 aryl­sulfonyl­imidazol­one ­hydro­chloride salt

The title compound, (S)‐(+)‐4‐[5‐(2‐oxo‐4,5‐di­hydro­imidazol‐1‐yl­sulfonyl)­indolin‐1‐yl­carbonyl]­anilinium chloride (S)‐(+)‐1‐[1‐(4‐amino­benzoyl)­indoline‐5‐sulfonyl]‐4‐phenyl‐4,5‐di­hydro­imidazol‐2‐one, C₂₄H₂₃N₄O₄S⁺·Cl^?·C₂₄H₂₂N₄O₄S, crystallizes in space group C2 from a CH₃OH/CH₂Cl₂ solution. In the crystal structure, there are two different conformers with their terminal C₆ aromatic rings mutually oriented at angles of 67.69 (14) and 61.16 (15)°. The distances of the terminal N atoms (of the two conformers) from the chloride ion are 3.110 (4) and 3.502 (4) Å. There are eight distinct hydrogen bonds, i.e. four N—H?Cl, three N—H?O and one N—H?N, with one N—H group involved in a bifurcated hydrogen bond with two acceptors sharing the H atom. C—H?O contacts assist in the overall hydrogen‐bonding process.