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.     

Hexakis(melaminium) tetrakis(dihydrogenphosphate) monohydrogenphosphate tetrahydrate

The crystal structure of the new melaminium salt, hexa­kis(2,4,6‐tri­amino‐1,3,5‐triazin‐1‐ium) tetrakis­(di­hydrogenphos­phate) mono­hydrogenphosphate tetrahydrate, 6C₃H₇N₆⁺·4H₂PO₄^?·HPO₄^2?·4H₂O, is built up from singly protonated melaminium residues, di­hydrogenphosphate and mono­hydrogen­phosphate anions, and water mol­ecules. The melaminium residues are interconnected by four N—H?N hydrogen bonds, forming chains along the [001] direction. These chains of melaminium residues form stacks aligned along [100]. The di­hydrogenphosphate anions interact with the mono­hydrogenphosphate anions via the H atoms and, together with hydrogen‐bonded dimers of the water mol­ecules, develop layers parallel to the (010) plane. The oppositely charged moieties interact via multiple N—H?O hydrogen bonds that stabilize the stacking structure.     

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.     

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.     

Hydro­gen‐bond networks in tris(4‐hydroxy­phenyl)­methane and its 1:1 molecular complex with 4,4′‐bi­pyridine

In tris(4‐hydroxy­phenyl)­methane (or 4,4′,4′′‐methane­triyl­tri­phenol), C₁₉H₁₆O₃, mol­ecules are connected by O—H⃛O hydrogen bonds [O⃛O = 2.662 (2) and 2.648 (2) Å] into two‐dimensional square networks that are twofold interpenetrated. In tris(4‐hydroxy­phenyl)­methane–4,4′‐bi­pyridine (1/1), C₁₉H₁₆O₃·C₁₀H₈N₂, trisphenol mol­ecules form rectangular networks via O—H⃛O [O⃛O = 2.694 (3) Å] and C—H⃛O [C⃛O = 3.384 (3) Å] hydrogen bonds. Bi­pyridine mol­ecules hydrogen bonded to phenol moieties [O⃛N = 2.622 (3) and 2.764 (3) Å] fill the voids to complete the structure.     

Hydrogen bonding in C-methylated nitroanilines: three triclinic examples with Z′ = 2 or 4

4-Methyl-2-nitro­aniline, (I), C₇H₈N₂O₂, crystallizes with two mol­ecules in the asymmetric unit. The mol­ecules both form intramolecular N—H⃛O hydrogen bonds and they are linked into hydrogen-bonded C₂²(12) chains in which the two independent mol­ecules alternate. 4,5-Di­methyl-2-nitro­aniline, (II), C₈H₁₀N₂O₂, also has Z′ = 2 and the two independent mol­ecules each form hydrogen-bonded C(6) chains. In 4-­methyl-3-nitro­aniline, (III), C₇H₈N₂O₂, there are four mol­ecules in the asymmetric unit. Molecules of two of these types are linked by N—H⃛O hydrogen bonds into molecular ladders containing R₄³(18) rings and the other two types independently form single C(7) chains.     

dl‐Proline

In the structure of dl ‐proline, C₅H₉NO₂, the mol­ecules are connected via classical inter­molecular N—H⋯O hydrogen bonds involving the amine and carbox­yl groups [N⋯O = 2.7129 (15) and 2.8392 (16) Å], and form chains along the b‐axis direction and parallel to (01). The chains are linked into sheets via weak non‐classical hydrogen bonds. The conformation of the mol­ecule and its packing are notably different from the monohydrated dl ‐proline form.     

4,4′-Bipyridine dihydrate at 130 K

The 4,4′-bi­pyridine mol­ecules in the title compound, C₁₀H₈N₂·2H₂O, are stacked in the direction of the crystallographic b axis. These stacks are connected via O—H⃛N and O—H⃛O hydrogen bonds to form sheets which lie parallel to (100). Chains of O—H⃛O hydrogen-bonded water mol­ecules are located between the bi­pyridine stacks. Altogether, four crystallographically independent water mol­ecules and two crystallographically independent bi­pyridine mol­ecules are involved.     

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.     

The epimeric 9‐oxobicyclo[3.3.1]nonane‐3‐carboxylic acids: hydrogen‐bonding patterns of the endo acid and the lactol of the exo acid

The two δ‐keto carboxylic acids of the title, both C₁₀H₁₄O₃, are epimeric at the site of carboxyl attachment. The endo (3α) epimer, (I), has its keto‐acid ring in a boat conformation, with the tilt of the carboxyl group creating conformational chirality. The mol­ecules form hydrogen bonds by centrosymmetric pairing of carboxyl groups across the corners of the chosen cell [O⃛O = 2.671 (2) Å and O—H⃛O = 179 (2)°]. Two close intermolecular C—H⃛O contacts exist for the ketone. The exo (3β) epimer exists in the closed ring–chain tautomeric form as the lactol, 8‐hydroxy‐9‐oxatri­cyclo­[5.3.1.0^3,8]­undecan‐10‐one, (II). The mol­ecules have conformational chirality, and the hydrogen‐bonding scheme involves intermolecular hydroxyl‐to‐carbonyl chains of mol­ecules screw‐related in b [O⃛O = 2.741 (2) Å and O—H⃛O = 177 (2)°].     

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.     

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.     

Unusual molecular conformation in dissymmetric propyl­ene‐linker compounds containing pyrazolo­[3,4‐d]­pyrimidine and phthalimide moieties

The crystal structure of 4,6‐bis(methylsulfanyl)‐1‐phthalimidopropyl‐1H‐pyrazolo[3,4‐d]pyrimidine, C₁₈H₁₇N₅O₂S₂, (VI), reveals an unusual folded conformation due to an apparent intramolecular C—H⃛π interaction between the 6‐methyl­­sul­fanyl and phenyl groups. However, the closely related compound 6‐methyl­sulfanyl‐1‐phthalimido­propyl‐4‐(pyrroli­din‐1‐yl)‐1H‐pyrazolo­[3,4‐d]­pyrimidine, C₂₁H₂₂N₆O₂S, (VII), exhibits a fully extended structure, devoid of any intramol­ecular C—H⃛π or π–π interactions. The crystal packing of both mol­ecules involves intermolecular stacking interactions due to aromatic π–π interactions. In addition, (VI) exhibits intermolecular C—H⃛O hydrogen bonding and (VII) exhibits dimerization of the mol­ecules through intermolecular C—H⃛N hydrogen bonding.     

4-(1-Adamantylamino)-2-amino-6-methoxy-5-nitrosopyrimidine

The title compound, C₁₅H₂₁N₅O₂, lies on a crystallographic mirror plane and is hydrogen bonded to neighbouring mol­ecules by infinite chains formed by combinations of strong N—H⃛N and soft C—H⃛O hydrogen bonds. The pyrimidine moiety shows extensive delocalization.     

2-[1-(Hydroxyimino)ethyl]-2,5,5-trimethylperhydropyrimidine–butane-2,3-dione monooxime (1/1)

The title compound, C₉H₁₉N₃O·C₄H₇NO₂, displays strong intramolecular O—H⃛N [O⃛N 2.6743 (13) Å] and N—H⃛N [N⃛N 2.6791 (15) Å] hydrogen bonds, and strong intermolecular O—H⃛N [O⃛N 2.7949 (15) Å] and N—H⃛O [N⃛O 3.0924 (16) Å] hydrogen bonds. This creates chains of per­hydro­pyrimidine mol­ecules, linked by hydrogen bonds. Each chain is linked to a partner chain, through hydrogen bonds to two butane-2,3-dione monooxime mol­ecules, in a structure reminiscent of a ladder.     

2‐Benzyl­amino‐6‐benzyl­oxy­pyrimidin‐4(3H)‐one: hydrogen‐bonded chains of rings linked into sheets by a π–π‐stacking interaction

The title compound, C₁₈H₁₇N₃O₂, crystallizes with Z′ = 2 in space group P2₁/c, and the two independent mol­ecules are approximate, but not exact, mirror images. The molecular–electronic structure is strongly polarized, and the mol­ecules are linked by paired N—H⃛O hydrogen bonds [H⃛O = 2.00–2.23 Å, N⃛O = 2.798 (3)–2.992 (3) Å and N—H⃛O = 145–151°] into two independent C(4)C(6)[(6)] chains of rings, which are linked into sheets by a single aromatic π–π‐stacking interaction.     

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.     

trans‐Bis­[2,3‐di­amino‐(R,S)‐propion­ato‐N,N′]­di­aqua­copper(II) dihydrate

The title copper complex, [Cu(dl ‐DAP)₂(H₂O)₂]·2H₂O or [Cu(C₃H₇N₂O₂)₂(H₂O)₂]·2H₂O, prepared from the non‐protein amino acid dl ‐2,3‐di­amino­propionic acid (dl ‐HDAP), has a center of symmetry and a distorted octahedral coordination, with four N atoms in equatorial positions and two water mol­ecules in apical sites. The water mol­ecule of crystallization is hydrogen bonded to the deprotonated carboxyl­ate group of the ligand.     

tert‐Butyl (3S,6R,9R)‐(5‐oxo‐3‐{[1(R)‐phenyl­ethyl]­carbamoyl}‐1,2,3,5,6,7,8,8a‐octa­hydro­indolizin‐6‐yl)­carbamate monohydrate at 95 K

The asymmetric unit of the title compound, C₂₂H₃₁N₃O₄·H₂O, incorporates one water mol­ecule, which is hydrogen bonded to the 3‐oxo O atom of the indolizidinone system. The two rings of the peptidomimetic mol­ecule are trans‐fused, with the six‐membered ring having a slightly distorted half‐chair conformation and the five‐membered ring having a perfect envelope conformation. The structure is stabilized by intermolecular O—H?O interactions between the water and adjacent peptide mol­ecules, and by N—H?O interactions between the peptide mol­ecules, which link the mol­ecules into infinite chains.