Melaminium acetate acetic acid solvate monohydrate

The crystals of the title new melaminium salt, 2,4,6‐tri­amino‐1,3,5‐triazin‐1‐ium acetate acetic acid solvate monohydrate, C₃H₇N₆⁺·CH₃COO^?·CH₃COOH·H₂O, are built up from singly protonated melaminium residues, acetate anions, and acetic acid and water mol­ecules. The melaminium residues are interconnected by N—H?N hydrogen bonds to form chains along the [010] direction. These chains of melaminium residues form stacks aligned along the a axis. The acetic acid mol­ecules interact with the acetate anions via the H atom of their carboxylic acid groups and, together with the water mol­ecules, form layers that are parallel to the (001) plane. The oppositely charged moieties interact via multiple N—H?O hydrogen bonds that stabilize a pseudo‐two‐dimensional stacking structure.     

Melaminium chloride hemihydrate

The crystals of a new melaminium salt, 2,4,6‐tri­amino‐1,3,5‐triazin‐1‐ium chloride hemihydrate, C₃H₇N₆⁺·Cl^?·0.5H₂O, are built up from single‐protonated melaminium residues, chloride anions and water mol­ecules. The protonated melaminium cations lie on a twofold axis, while the chloride anions and water mol­ecule lie on the m plane. The melaminium residues are interconnected by N—H?N hydrogen bonds, forming chains parallel to the (001) plane. The chains of melaminium residues form a three‐dimensional network through hydrogen‐bond interactions with chloride anions and water mol­ecules.     

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.     

Melaminium glutarate monohydrate

The crystal structure of the title new melaminium salt, 2,4,6‐tri­amino‐1,3,5‐triazin‐1‐ium glutarate monohydrate, C₃H₇N₆⁺·C₅H₇­O₄^?·H₂O, is built up from singly protonated melaminium residues, mono‐dissociated glutarate ions and water mol­ecules. The melaminium residues are interconnected by four N—H?N hydrogen bonds to form chains. These chains of melaminium residues form a stacking structure. The glutarate anions form a hydrogen‐bonded zigzag polymer of the form [?HOOC(CH₂)₃COO?HOOC(CH₂)₃COO?]_n. The oppositely charged moieties, i.e. the melaminium and glutarate chains, form two‐dimensional polymeric sheets. These sheets are interconnected by O—H?O hydrogen bonds between the COO^? moieties and the water mol­ecules, and these hydrogen bonds stabilize the stacking structure.     

Melaminium maleate monohydrate

In the title compound, 2,4,6‐tri­amino‐1,3,5‐triazin‐1‐ium maleate monohydrate, C₃H₇N₆⁺·C₄H₃O₄⁻·H₂O, containing singly protonated melaminium residues, maleate(1−) anions and water mol­ecules, the components are linked by hydrogen bonds into a three‐dimensional framework structure. The melaminium residues are connected by two pairs of N—H⋯N hydrogen bonds into chains in the form of stacks, with a distance of 3.26 (1) Å between the triazine rings, clearly indicating π–π interactions. The maleate anion contains an intramolecular O—H⋯O hydrogen bond and the anions interact with the water mol­ecules via O—H⋯O hydrogen bonds, forming zigzag chains, also in the form of stacks, in which the almost‐planar maleate anions are separated by 3.26 (1) Å. The experimental geometries of the ions are compared with molecular‐orbital calculations of their gas‐phase geometries.     

Bis­(melaminium) sulfate dihydrate

The crystals of a new melaminium salt, bis(2,4,6-tri­amino-1,3,5-triazin-1-ium) sulfate dihydrate, 2C₃H₇N₆⁺·SO₄²⁻·2H₂O, are built up from monoprotonated melaminium(1+) residues, sulfate(2−) anions and water mol­ecules. The SO₄²⁻ ion has a slightly distorted tetrahedral geometry. The melaminium residues are interconnected by N—H⋯N hydrogen bonds, forming chains. The chains of melaminium residues develop a three-dimensional network through multiple donor–acceptor hydrogen-bond interactions with sulfate anions and water mol­ecules.     

Melaminium bis(4‐hydroxybenzenesulfonate) dihydrate

The crystals of a new melaminium salt, 2,4,6‐tri­amino‐1,3,5‐triazine‐1,3‐diium bis(4‐hydroxy­benzene­sulfonate) dihydrate, C₃H₈N₆²⁺·2C₆H₅O₄S^?·2H₂O, are built up from doubly proton­ated melaminium(2+) residues, dissociated p‐phenol­sulfonate anions and water mol­ecules. The doubly protonated melaminium dication lies on a twofold axis. The hydroxyl group of the p‐hydroxybenzenesulfonate residue is roughly coplanar with the phenyl ring [dihedral angle 13 (2)°]. A combination of ionic and donor–acceptor hydrogen‐bond interactions link the melaminium and p‐hydroxybenzenesulfonate residues and the water mol­ecules to form a three‐dimensional network.     

4,5‐Di­azafluoren‐9‐one benzoyl­hydrazone monohydrate

The title compound, C₁₈H₁₂N₄O·H₂O, adopts the keto tautomeric form and the azomethine C=N double bond is in the E configuration. The dihedral angle between the planes of the di­aza­fluorene moiety and the phenyl ring is 11.3 (1)°. In the solid state, the mol­ecules form infinite chain‐like structures via O—H?N hydrogen bonds involving the water mol­ecules and di­aza­fluorene moieties.     

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.     

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 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.     

Cocrystallization of melaminium levulinate monohydrate

Crystals of 2,4,6‐tri­amino‐1,3,5‐triazin‐1‐ium levulinate (4‐oxo­pentanoate) monohydrate, C₃H₇N₆⁺·C₅H₇O₃⁻·H₂O, are formed via self‐assembled hydrogen bonding by cocrystallization of mel­amine and levulinic acid. Two N—H⋯N hydrogen bonds and four N—H⋯O hydrogen bonds connect two melaminium entities such that each of two pairs of N—H⋯O bonds bridges two H atoms belonging to the amine groups of two different melaminium cations via the carbonyl O atom of one levulinate mol­ecule.     

The antifolate trimetrexate: ­observation of the enzyme‐binding conformation

The crystal structure of the title compound contains four 2,4‐di­amino‐5‐methyl‐6‐[(3,4,5‐tri­methoxy­anilino)­methyl]­quin­az­oline mol­ecules, two di­methyl sulfoxide mol­ecules and three water mol­ecules in the asymmetric unit, i.e. 4C₁₉H₂₃N₅O₃·2C₂H₆OS·3H₂O. All four quinazoline mol­ecules adopt trans,gauche conformations. An extensive hydrogen‐bond network involving N?N base‐pairing interactions, as well as the di­methyl sulfoxide and water mol­ecules, stabilizes the crystal structure.     

Hydrogen‐bonded one‐dimensional networks in 1:1 complexes of N,N′‐bis(2‐pyridyl)aryldiamines with anilic acid

The 1:1 complexes N,N′‐bis(2‐pyridyl)­benzene‐1,4‐di­amine–anilic acid (2,5‐di­hydroxy‐1,4‐benzo­quinone) (1/1), C₁₆H₁₄N₄·C₆H₄O₄, (I), and N,N′‐bis(2‐pyridyl)­bi­phenyl‐4,4′‐di­amine–anilic acid (1/1), C₂₂H₁₈N₄·C₆H₄O₄, (II), have been prepared and their solid‐state structures investigated. The component mol­ecules of these complexes are connected via conventional N—H?O and O—H?N hydrogen bonds, leading to the formation of an infinite one‐dimensional network generated by the cyclic motif R(9). The anilic acid molecules in both crystal structures lie around inversion centres and the observed bond lengths are typical for the neutral mol­ecule. Nevertheless, the pyridine C—N—C angles [120.9 (2) and 120.13 (17)° for complexes (I) and (II), respectively] point to a partial H‐atom transfer from anilic aicd to the bispyridyl­amine, and hence to H‐atom disorder in the OHN bridge. The bispyridyl­amine mol­ecules of (I) and (II) also lie around inversion centres and exhibit disorder of their central phenyl rings over two positions.     

A di­deoxy­dide­hydro­nucleoside derivative

We have synthesized a di­deoxy­dide­hydro­nucleoside derivative, 2(S)‐acetoxymethyl‐4‐[4‐amino‐2‐oxopyrimidin‐1(2H)‐yl]‐2,5‐di­hydro­furan, C₁₁H₁₃N₃O₄, which is an analogue of the potently anti‐HIV active compound, di­deoxy‐dide­hydro­cytidine (d4C). The target compound crystallizes with two mol­ecules in the asymmetric unit that differ primarily in the orientation of the C6′‐acetyl group. One mol­ecule has an extended conformation and the orientation of the acetyl group in the second mol­ecule gives an unusual hooked‐shaped conformation. The two conformers form A–B dimers via N—H?N hydrogen bonds. The dimers link via N—H?O hydrogen bonds to form chains parallel to the b cell axis.     

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.     

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.     

(±)‐6‐Benzyl‐3,3‐di­methyl­morpholine‐2,5‐dione and its 5‐mono­thio and 2,5‐di­thio derivatives

The morpholine ring of the title dione, C₁₃H₁₅NO₃, shows a boat conformation that is distorted towards a twist‐boat, with the boat ends being the two Csp³ atoms of the ring. The benzyl substituent is in the favoured `exo' position. In the mono­thione derivative, (±)‐6‐benzyl‐3,3‐di­methyl‐5‐thioxo­morpholin‐2‐one, C<sub>13</sub>H<sub>15</sub>NO<sub>2</sub>S, this ring has a much flatter conformation that is midway between a boat and an envelope, with the di­methyl end being almost planar. The orientation of the benzyl group is `endo'. The di­thione derivative, (±)‐6‐benzyl‐3,3‐di­methyl­morpholine‐2,5‐di­thione, C₁₃H₁₅N­OS₂, has two symmetry‐independent mol­ecules, which show different puckering of the morpholine ring. One mol­ecule has a flattened envelope conformation distorted towards a screw‐boat, while the conformation in the other mol­ecule is similar to that in the mono­thione derivative. Intermolecular hydrogen bonds link the mol­ecules in the three compounds, respectively, into centrosymmetric dimers, infinite chains, and dimers made up of one of each of the symmetry‐independent mol­ecules.     

Adducts of 1,1,1‐tris(4‐hydroxy­phenyl)­ethane with 1,2‐bis(4‐pyridyl)­ethane and 1,2‐bis(4‐pyridyl)­ethene: continuously interwoven structures in three dimensions

In the adduct 1,2‐bis(4‐pyridyl)­ethane–1,1,1‐tris(4‐hydroxy­phenyl)­ethane (1/2), C₁₂H₁₂N₂·2C₂₀H₁₈O₃, the bipyridyl component lies across an inversion centre in P. The tris‐phenol mol­ecules [systematic name: 4,4′,4′′‐(ethane‐1,1,1‐triyl)­triphenol] are linked by O—H?O hydrogen bonds to form sheets built from R(38) rings, and symmetry‐related pairs of sheets are linked by the bipyridyl mol­ecules via O—H?N hydrogen bonds to form open bilayers. Each bilayer is interwoven with two adjacent bilayers, forming a continuous three‐dimensional structure. In the adduct 1,2‐bis(4‐pyridyl)­ethene–1,1,1‐tris(4‐hydroxy­phenyl)­ethane–methanol (1/1/1), C₁₂H₁₀N₂·C₂₀H₁₈O₃·CH₄O, the mol­ecules are linked by O—H?O and O—H?N hydrogen bonds into three interwoven three‐dimensional frameworks, generated by single spiral chains along [010] and [001] and a triple‐helical spiral along [100].     

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.