Brucine salts of l‐α‐hydr­oxy acids: brucinium hydrogen (S)‐malate penta­hydrate and anhydrous brucinium hydrogen (2R,3R)‐tartrate at 130 K

The structures of two brucinium (2,3‐dimeth­oxy‐10‐oxostrychnidinium) salts of the α‐hydr­oxy acids l ‐malic acid and l ‐tartaric acid, namely brucinium hydrogen (S)‐malate penta­hydrate, C₂₃H₂₇N₂O₄⁺·C₄H₅O₅⁻·5H₂O, (I), and anhydrous brucinium hydrogen (2R,3R)‐tartrate, C₂₃H₂₇N₂O₄⁺·C₄H₅O₆⁻,(II), have been determined at 130 K. Compound (I) has two brucinium cations, two hydrogen malate anions and ten water mol­ecules of solvation in the asymmetric unit, and forms an extensively hydrogen‐bonded three‐dimensional framework structure. In compound (II), the brucinium cations form the common undulating brucine sheet substructures, which accommodate parallel chains of head‐to‐tail hydrogen‐bonded tartrate anion species in the inter­stitial cavities.     

l‐Prolinium tartrate

In the title salt, C₅H₁₀NO₂⁺·C₄H₅O₆^?, proline exists as a cation and the tartaric acid as a semi‐tartrate anion. The semi‐tartrate ions form hydrogen‐bonded strings along the c axis. These strings are interconnected through the proline mol­ecules, forming a layered network parallel to the bc plane. The proline mol­ecules, however, do not directly interact among themselves, except for a weak C—H?O hydrogen bond.     

Hydro­gen bonding in proton‐transfer compounds of 5‐sulfosalicylic acid with bicyclic heteroaromatic Lewis bases

The crystal structures of quinolinium 3‐carboxy‐4‐hydroxy­benzene­sulfonate trihydrate, C₉H₈N⁺·C₇H₅O₆S⁻·3H₂O, (I), 8‐hydroxy­quinolinium 3‐carboxy‐4‐hydroxy­benzene­sulfonate monohydrate, C₉H₈NO⁺·C₇H₅O₆S⁻·H₂O, (II), 8‐amino­quinolinium 3‐carboxy‐4‐hydroxy­benzene­sulfonate dihydrate, C₉H₉N₂⁺·C₇H₅O₆S⁻·2H₂O, (III), and 2‐carboxy­quinolinium 3‐carboxy‐4‐hydroxy­benzene­sulfonate quinolinium‐2‐carboxylate, C₁₀H₈NO₂⁺·C₇H₅O₆S⁻·C₁₀H₇NO₂, (IV), four proton‐transfer compounds of 5‐sulfosalicylic acid with bicyclic heteroaromatic Lewis bases, reveal in each the presence of variously hydrogen‐bonded polymers. In only one of these compounds, viz. (II), is the protonated quinolinium group involved in a direct primary N⁺—H⋯O(sulfonate) hydrogen‐bonding interaction, while in the other hydrates, viz. (I) and (III), the water mol­ecules participate in the primary intermediate interaction. The quinaldic acid (quinoline‐2‐carboxylic acid) adduct, (IV), exhibits cation–cation and anion–adduct hydrogen bonding but no direct formal heteromolecular interaction other than a number of weak cation–anion and cation–adduct π–π stacking associations. In all other compounds, secondary interactions give rise to network polymer structures.     

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).     

Three 4‐amino­quinolines of anti­malarial interest

The structures of three compounds with potential anti­malarial activity are reported. In N,N‐diethyl‐N′‐(7‐iodo­quinolin‐4‐yl)ethane‐1,2‐diamine, C₁₅H₂₀IN₃, (I), the mol­ecules are linked into ribbons by N—H⋯N and C—H⋯N hydrogen bonds. In N‐(7‐bromo­quinolin‐4‐yl)‐N′,N′‐diethyl­ethane‐1,2‐diamine dihydrate, C₁₅H₂₀BrN₃·2H₂O, (II), two amino­quino­line mol­ecules and four water mol­ecules form an R₅⁴(13) hydrogen‐bonded ring which links to its neighbours to form a T5(2) one‐dimensional infinite tape with pendant hydrogen bonds to the amino­quinolines. The phosphate salt 7‐chloro‐4‐[2‐(diethyl­ammonio)ethyl­amino]quinolinium bis­(dihydrogen­phosphate) phospho­ric acid, C₁₅H₂₂ClN₃²⁺·2H₂PO₄⁻·H₃PO₄, (III), was prepared in order to establish the protonation sites of these compounds. The phosphate ions form a two‐dimensional hydrogen‐bonded sheet, while the amino­quino­line cations are linked to the phosphates by N—H⋯O hydrogen bonds from each of their three N atoms. While the conformation of the quinoline region hardly varies between (I), (II) and (III), the amino side chain is much more flexible and adopts a significantly different conformation in each case. Aromatic π–π stacking inter­actions are the only supramolecular inter­actions seen in all three structures.     

Supra­molecular hydrogen‐bonding networks in bis­(adeninium) phthalate phthalic acid 1.45‐hydrate

In the title compound, 2C₅H₆N₅⁺·C₈H₄O₄²⁻·C₈H₆O₄·1.45H₂O, the asymmetric unit comprises two adeninium cations, two half phthalate anions with crystallographic C₂ symmetry, one neutral phthalic acid mol­ecule, and one fully occupied and one partially occupied site (0.45) for water mol­ecules. The adeninium cations form N—H⋯O hydrogen bonds with the phthalate anions. The cations also form infinite one‐dimensional polymeric ribbons via N—H⋯N inter­actions. In the crystal packing, hydrogen‐bonded columns of cations, anions and phthalate anions extend parallel to the c axis. The water mol­ecules crosslink adjacent columns into hydrogen‐bonded layers.     

1:1 Hetero‐assembly of 2‐amino­pyrimidine and (+)‐camphoric acid

In the title cocrystal, 2‐aminopyrimidine–(+)‐camphoric acid (1/1), C₄H₅N₃·C₁₀H₁₆O₄, the 2‐amino­pyrimidine forms two eight‐membered hydrogen‐bonded rings with two different camphoric acid mol­ecules. This results in infinite wave‐like chains of mol­ecules in which neighbouring chains are connected by weak C—H?O contacts. The five‐membered ring in the acid mol­ecule adopts a half‐chair conformation.     

The 1:1 adduct of hexa­methyl­ene­tetramine (HMT) with racemic trans‐1,2‐cyclo­hexane­di­carboxylic acid (CDA)

Hexa­methyl­ene­tetramine and rac‐trans‐1,2‐cyclo­hexane­di­carboxylic acid crystallize in a 1:1 ratio as a neutral molecular adduct, C₆H₁₂N₄·C₈H₁₂O₄. Two di­carboxylic acid mol­ecules and two tetr­amine mol­ecules form a hydrogen‐bonded ring, in the shape of a rhombus, which lies on a crystallographic twofold axis bisecting the two diacid mol­ecules. The O—H⋯N hydrogen bonds have lengths 2.6808 (19) and 2.6518 (19) Å, and, in each ring, both acid mol­ecules have the same handedness.     

Three‐dimensional hydrogen‐bonded structures in the 1:1 proton‐transfer compounds of l‐tartaric acid with the associative‐group monosubstituted pyridines 3‐aminopyridine, 3‐carboxypyridine (nicotinic acid) and 2‐carboxypyridine (picolinic acid)

The 1:1 proton‐transfer compounds of l ‐tartaric acid with 3‐aminopyridine [3‐aminopyridinium hydrogen (2R,3R)‐tartrate dihydrate, C₅H₇N₂⁺·C₄H₅O₆⁻·2H₂O, (I)], pyridine‐3‐carboxylic acid (nicotinic acid) [anhydrous 3‐carboxypyridinium hydrogen (2R,3R)‐tartrate, C₆H₆NO₂⁺·C₄H₅O₆⁻, (II)] and pyridine‐2‐carboxylic acid [2‐carboxypyridinium hydrogen (2R,3R)‐tartrate monohydrate, C₆H₆NO₂⁺·C₄H₅O₆⁻·H₂O, (III)] have been determined. In (I) and (II), there is a direct pyridinium–carboxyl N⁺—H...O hydrogen‐bonding interaction, four‐centred in (II), giving conjoint cyclic R₁²(5) associations. In contrast, the N—H...O association in (III) is with a water O‐atom acceptor, which provides links to separate tartrate anions through O_hydroxy acceptors. All three compounds have the head‐to‐tail C(7) hydrogen‐bonded chain substructures commonly associated with 1:1 proton‐transfer hydrogen tartrate salts. These chains are extended into two‐dimensional sheets which, in hydrates (I) and (III) additionally involve the solvent water molecules. Three‐dimensional hydrogen‐bonded structures are generated via crosslinking through the associative functional groups of the substituted pyridinium cations. In the sheet struture of (I), both water molecules act as donors and acceptors in interactions with separate carboxyl and hydroxy O‐atom acceptors of the primary tartrate chains, closing conjoint cyclic R₄⁴(8), R₃⁴(11) and R₃³(12) associations. Also, in (II) and (III) there are strong cation carboxyl–carboxyl O—H...O hydrogen bonds [O...O = 2.5387 (17) Å in (II) and 2.441 (3) Å in (III)], which in (II) form part of a cyclic R₂²(6) inter‐sheet association. This series of heteroaromatic Lewis base–hydrogen l ‐tartrate salts provides further examples of molecular assembly facilitated by the presence of the classical two‐dimensional hydrogen‐bonded hydrogen tartrate or hydrogen tartrate–water sheet substructures which are expanded into three‐dimensional frameworks via peripheral cation bifunctional substituent‐group crosslinking interactions.     

7‐Carboxyl­ato‐8‐hydroxy‐2‐methyl­quinolinium monohydrate and 7‐carboxy‐8‐hydroxy‐2‐methyl­quinolinium chloride monohydrate at 100 K

Both 7‐carboxyl­ato‐8‐hydroxy‐2‐methyl­quinolinium monohydrate, C₁₁H₉NO₃·H₂O, (I), and 7‐carboxy‐8‐hydroxy‐2‐methyl­quinolinium chloride monohydrate, C₁₁H₁₀NO₃⁺·Cl⁻·H₂O, (II), crystallize in the centrosymmetric P space group. Both compounds display an intramolecular O—H⋯O hydrogen bond involving the hydroxy group; this hydrogen bond is stronger in (I) due to its zwitterionic character [O⋯O = 2.4449 (11) Å in (I) and 2.5881 (12) Å in (II)]. In both crystal structures, the HN⁺ group participates in the stabilization of the structure via intermolecular hydrogen bonds with water mol­ecules [N⋯O = 2.7450 (12) Å in (I) and 2.8025 (14) Å in (II)]. In compound (II), a hydrogen‐bond network connects the Cl⁻ anion to the carboxylic acid group [Cl⋯O = 2.9641 (11) Å] and to two water mol­ecules [Cl⋯O = 3.1485 (10) and 3.2744 (10) Å].     

One‐dimensional hydrogen‐bonded structures in the 1:1 proton‐transfer compounds of 4,5‐dichlorophthalic acid with 8‐hydroxyquinoline, 8‐aminoquinoline and quinoline‐2‐carboxylic acid (quinaldic acid)

The structures of the 1:1 proton‐transfer compounds of 4,5‐dichlorophthalic acid with 8‐hydroxyquinoline, 8‐aminoquinoline and quinoline‐2‐carboxylic acid (quinaldic acid), namely anhydrous 8‐hydroxyquinolinium 2‐carboxy‐4,5‐dichlorobenzoate, C₉H₈NO⁺·C₈H₃Cl₂O₄⁻, (I), 8‐aminoquinolinium 2‐carboxy‐4,5‐dichlorobenzoate, C₉H₉N₂⁺·C₈H₃Cl₂O₄⁻, (II), and the adduct hydrate 2‐carboxyquinolinium 2‐carboxy‐4,5‐dichlorobenzoate quinolinium‐2‐carboxylate monohydrate, C₁₀H₈NO₂⁺·C₈H₃Cl₂O₄⁻·C₁₀H₇NO₂·H₂O, (III), have been determined at 130 K. Compounds (I) and (II) are isomorphous and all three compounds have one‐dimensional hydrogen‐bonded chain structures, formed in (I) through O—H...O_carboxyl extensions and in (II) through N⁺—H...O_carboxyl extensions of cation–anion pairs. In (III), a hydrogen‐bonded cyclic R₂²(10) pseudo‐dimer unit comprising a protonated quinaldic acid cation and a zwitterionic quinaldic acid adduct molecule is found and is propagated through carboxylic acid O—H...O_carboxyl and water O—H...O_carboxyl interactions. In both (I) and (II), there are also cation–anion aromatic ring π–π associations. This work further illustrates the utility of both hydrogen phthalate anions and interactive‐group‐substituted quinoline cations in the formation of low‐dimensional hydrogen‐bonded structures.     

Copper(II) and zinc(II) complexes of pyridine‐2,6‐di­carboxyl­ic acid

The title compounds, bis­(pyridine‐2,6‐di­carboxyl­ato‐N,O,O′)copper(II) monohydrate, [Cu(C₇H₄NO₄)₂]·H₂O, andbis(pyridine‐2,6‐dicarboxylato‐N,O,O′)zinc(II) trihydrate, [Zn(C₇H₄NO₄)₂]·3H₂O, have distorted octahedral geometries about the metal centres. Both metal ions are bonded to four O atoms and two pyridyl‐N atoms from the two terdentate ligand mol­ecules, which are nearly perpendicular to each other. The copper(II) complex has twofold crystallographic symmetry and contains two different ligand mol­ecules, one of which is neutral and another doubly ionized. In contrast, the zinc(II) complex contains two identical singly ionized ligand mol­ecules. Both crystal structures are stabilized by O—H?O intermolecular hydrogen bonds between the complex and the water mol­ecules.     

9(R)‐[6(R)‐Hydroxy­methyl‐1‐oxa‐4‐thia­cyclo­hexan‐2‐yl]hypoxanthine–water (4/3), a nucleoside analogue

The title compound, 9(R)‐[6(R)‐hydroxy­methyl‐1‐oxa‐4‐thia­cyclo­hexan‐2‐yl]‐1,9‐di­hydro‐6H‐purin‐6‐one–water (4/3), C₁₀H₁₂N₄O₃S·0.75H₂O, crystallizes in the triclinic space group P1 with four mol­ecules in the asymmetric unit and 0.75 waters of hydration per mol­ecule. The structure was refined to an R value of 0.072 for 3382 observed reflections. The four crystallographically independent mol­ecules are designated A, B, C and D. All four oxa­thia­ne rings adopt the chair conformation and the purine bases are in an anti orientation with respect to the sugar moieties. Molecules A and D and mol­ecules C and B are base paired by a single hydrogen bond of the type N—H?N. These base pairs are again hydrogen bonded to their translated pairs in the direction of a cell diagonal.     

Ribbons of hydrogen‐bonded rings in the 1:2 complex of pyromellitic acid and di­methyl sulfoxide

In the title complex, pyromellitic acid–di­methyl sulfoxide (1/­2), C₁₀H₆O₈·2C₂H₆OS, mol­ecules of pyromellitic acid (1,2,4,5‐benzene­tetra­car­box­ylic acid) and di­methyl sulfoxide, the latter being well ordered, are linked to each other by O—­H⃛O hydrogen bonds. The formula unit displays crystallographic inversion symmetry. The packing consists of ribbons of hydrogen‐bonded rings that can be described by graph set C(10)R(18).     

4‐(4‐Hydro­xy­benzyl­idene­amino)‐4H‐1,2,4‐triazole hemihydrate

In the title compound, 4‐(4H‐1,2,4‐triazol‐4‐yl­imino­methyl)­phenol hemi­hydrate, C₉H₈N₄O·0.5H₂O or (I)·0.5H₂O, mol­ecules of (I) are arranged as layers running along the b axis through intermolecular O—H?N and C—H?O hydrogen bonds. These layers are stabilized by hydrogen‐bonded water mol­ecules to form three‐dimensional networks.     

2‐Aminopyridinium–succinate–succinic acid (2/1/1)

In the title compound, 2C₅H₇N₂⁺·C₄H₄O₄^2?·C₄H₆O₄, cyclic eight‐membered hydrogen‐bonded rings exist involving 2‐amino­pyridinium and succinate ions. The succinic acid and succinate moieties lie on inversion centres. Succinic acid mol­ecules and succinate ions are linked into zigzag chains by O—H?O hydrogen bonds, with O?O distances of 2.6005 (16) Å.     

Bis­(melaminium) dl‐malate tetrahydrate

The crystal structure of the title melaminium salt, bis(2,4,6‐tri­amino‐1,3,5‐triazin‐1‐ium) dl ‐malate tetrahydrate, 2C₃H₇N₆⁺·C₄H₄O₅²⁻·4H₂O, consists of singly protonated melaminium residues, dl ‐malate dianions and water mol­ecules. The melaminium residues are connected into chains by four N—H⃛N hydrogen bonds, and these chains form a stacking structure along the c axis. The dl ‐malate dianions form hydrogen‐bonded chains and, together with hydrogen‐bonded water mol­ecules, form a layer parallel to the (100) plane. The conformation of the malate ion is compared with an ab initio molecular‐orbital calculation. The oppositely charged moieties, i.e. the stacks of melaminium chains and hydrogen‐bonded dl ‐malate anions and water mol­ecules, form a three‐dimensional polymeric structure, in which N—H⃛O hydrogen bonds stabilize the stacking.     

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.     

Two salts of di‐p‐toluoyltartaric acid with aromatic amines

The structures of bis­[(R)‐(+)‐1‐phenyl­ethyl­ammonium] (2R,3R)‐(−)‐2,3‐di‐p‐toluoyloxybutane­dioate methanol disolvate monohydrate, 2C₈H₁₂N⁺·C₂₀H₁₆O₈²⁻·2CH₄O·H₂O, (I), and bis­(benzyl­ammonium) (2R,3R)‐(−)‐2,3‐di‐p‐toluoyl­oxy­butane­­dioate dihydrate, 2C₇H₁₀N⁺·C₂₀H₁₆O₈²⁻·2H₂O, (II), exhibit extensive hydrogen bonding, with (N—)H⋯O and (O—)H⋯O distances in the ranges 2.716 (2)–2.929 (3) and 2.687 (2)–2.767 (2) Å, respectively, in (I), and 2.673 (2)–2.888 (2) and 2.785 (2)–2.931 (2) Å, respectively, in (II). The amine groups are protonated and the carboxyl­ate groups of the tartrate anions are fully deprotonated. The conformation of the toluoyltartrate anion and its mol­ecular parameters are similar in both structures.     

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.