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.     

Tris(2‐cyanoethyl) isocyanurate

The title compound, 1,3,5‐tris(2‐cyano­ethyl)‐1,3,5‐triazine‐2,4,6(1H,3H,5H)‐trione, C₁₂H₁₂N₆O₃, forms a layered structure stabilized by C—H?O and C—H?N hydrogen bonds.     

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.     

N‐(3H‐Thia­zol‐2‐yl­idene)­nitr­amine and N‐methyl‐N‐(thia­zol‐2‐yl)­nitr­amine

The geometries of the thia­zole ring and the nitr­amino groups in N‐(3H‐thia­zol‐2‐yl­idene)­nitr­amine, C₃H₃N₃O₂S, (I), and N‐­methyl‐N‐(thia­zol‐2‐yl)­nitr­amine, C₄H₅N₃O₂S, (II), are very similar. The nitr­amine group in (II) is planar and twisted along the C—N bond with respect to the thia­zole ring. In both structures, the asymmetric unit includes two practically equal mol­ecules. In (I), the mol­ecules are arranged in layers connected to each other by N—H⋯N and much weaker C—H⋯O hydrogen bonds. In the crystal structure of (II), the mol­ecules are arranged in layers bound to each other by both weak C—H⋯O hydrogen bonds and S⋯O dipolar interactions.     

Three N2‐benzoyl­oxybenz­amidines: sheet structures built from hard and soft hydrogen bonds and aromatic π–π stacking interactions

Molecules of the title compounds N²‐(benzoyl­oxy)­benz­ami­dine, C₁₄H₁₂N₂O₂, (I), N²‐(2‐hydroxy­benzoyl­oxy)­benz­ami­dine, C₁₄H₁₂N₂O₃, (II), and N²‐benzoyloxy‐2‐hydroxybenzamidine, C₁₄H₁₂N₂O₃, (III), all have extended chain conformations, with the aryl groups remote from one another. In (I), the mol­ecules are linked into chains by a single N—H⋯N hydrogen bond [H⋯N = 2.15 Å, N⋯N = 3.029 (2) Å and N—H⋯N = 153°] and these chains are linked into sheets by means of aromatic π–π stacking interactions. There is one intramolecular O—H⋯O hydrogen bond in (II), and a combination of one three‐centre N—H⋯(N,O) hydrogen bond [H⋯N = 2.46 Å, H⋯O = 2.31 Å, N⋯N = 3.190 (2) Å, N⋯O = 3.146 (2) Å, N—H⋯N = 138° and N—H⋯O = 154°] and one two‐centre C—H⋯O hydrogen bond [H⋯O = 2.46 Å, C⋯O = 3.405 (2) Å and C—H⋯O = 173°] links the mol­ecules into sheets. In (III), an intramolecular O—H⋯N hydrogen bond and two N—H⋯O hydrogen bonds [H⋯O = 2.26 and 2.10 Å, N⋯O = 2.975 (2) and 2.954 (2) Å, and N—H⋯O = 138 and 163°] link the molecules into sheets.     

4,4′‐Butane‐1,4‐diylbis[3‐ethyl‐1H‐1,2,4‐triazol‐5(4H)‐one] and 4‐hydr­oxy‐3‐n‐prop­yl‐1H‐1,2,4‐triazol‐5(4H)‐one

The title compounds, C₁₂H₂₀N₆O₂, (I), and C₅H₉N₃O₂, (II), display the characteristic features of 1,2,4‐triazole derivatives. Compound (I) lies about an inversion centre which is at the mid‐point of the central C—C bond. Compound (II) also contains a planar 1,2,4‐triazole ring but differs from (I) in that it has a hydr­oxy group attached to the ring. Mol­ecules of (I) are held together in the crystal structure by inter­molecular N—H⋯O contacts and by weak π–π stacking inter­actions between the 1,2,4‐triazole moieties. Compound (II) contains inter­molecular O—H⋯O and N—H⋯O hydrogen bonds.     

Tris(1H‐benzimidazol‐2‐yl­meth­yl)­amine–solvent adducts

The tris­(1H‐benzimidazol‐2‐yl­meth­yl)­amine (ntb) mol­ecule crystallizes in different solvent systems, resulting in two kinds of adduct, namely the monohydrate, C₂₄H₂₁N₇·H₂O or ntb·H₂O, (I), and the acetonitrile–methanol–water (1/0.5/1.5) solvate, C₂₄H₂₁N₇·C₂H₃N·0.5CH₄O·1.5H₂O or ntb·1.5H₂O·0.5MeOH·MeCN, (II). In both cases, ntb adopts a tripodal mode to form hydrogen bonds with a solvent water mol­ecule via two N—H⋯O and one O—H⋯N hydrogen bond. In (I), the ntb·H₂O adduct is further assembled into a two‐dimensional network by N—H⋯N and O—H⋯N hydrogen bonds, while in (II), a double‐stranded one‐dimensional chain structure is assembled via N—H⋯O and O—H⋯O hydrogen bonds, with the acetonitrile mol­ecules located inside the cavities of the chain structure.     

Supra­molecular motifs in 1‐(2‐cyano­ethyl)thymine and 1‐(3‐cyano­propyl)­thymine

In both 1‐(2‐cyano­ethyl)thymine [systematic name: 3‐(5‐methyl‐2,4‐dioxo‐1,2,3,4‐tetra­hydro­pyrimidin‐1‐yl)propane­nitrile], C₈H₉N₃O₂, (I), and 1‐(3‐cyano­propyl)thymine [systematic name: 4‐(5‐methyl‐2,4‐dioxo‐1,2,3,4‐tetra­hydro­pyrimidin‐1‐yl)butane­nitrile], C₉H₁₁N₃O₂, (II), the core of the supra­molecular structure is formed by centrosymmetric dimers generated by N—H⋯O hydrogen bonds. Further weak hydrogen bonds of C—H⋯O and C—H⋯N types generate mol­ecular tapes and sheets that resemble those in uracil and its methyl derivatives. The steric hindrance that arises from the cyano­alkyl substituents perturbs the conformations of the tapes and sheets.     

Isomorphous crystals of strychninium 4‐chloro­benzoate and strychninium 4‐nitro­benzoate

In strychninium 4‐chloro­benzoate, C₂₁H₂₃N₂O₂⁺·C₇H₄ClO₂⁻, (I), and strychninium 4‐nitro­benzoate, C₂₁H₂₃N₂O₂⁺·C₇H₄NO₄⁻, (II), the strychninium cations form pillars stabilized by C—H⋯O and C—H⋯π hydrogen bonds. Channels between the pillars are occupied by anions linked to one another by C—H⋯π hydrogen bonds. The cations and anions are linked by ionic N—H⁺⋯O⁻ and C—H⋯X hydrogen bonds, where X = O, π and Cl in (I), and O and π in (II).     

Dichloro­{2‐[2‐(dimethyl­ammonio)­ethyl­imino­meth­yl]‐4‐nitro­phenolato}­zinc(II) in unsolvated and hemihydrate forms

The two title complexes, [ZnCl₂(C₁₁H₁₅N₃O₃)], (I), and [ZnCl₂(C₁₁H₁₅N₃O₃)]·0.5H₂O, (II), are mononuclear zinc(II) compounds. In both structures, the Zn^II atom is four‐coordinated in a tetra­hedral configuration by one imine N atom and one phenolate O atom of a Schiff base, and by two Cl atoms. The structure of each of the two zinc(II) complex molecules of (II) is similar to that of (I). In (I), the mol­ecules are linked through inter­molecular hydrogen bonds, forming a three‐dimensional framework. In (II), the solvent water mol­ecules are linked to the zinc(II) moieties through inter­molecular O—H⋯O and O—H⋯Cl hydrogen bonds. The mol­ecules in (II) are further linked via other inter­molecular hydrogen bonds, forming a three‐dimensional framework.     

3,3a‐Dihydrocyclo­penta­[b]­chromen‐1(2H)‐ones from the reaction of salicylaldehyde and 2‐cyclo­penten‐1‐one

The two title chromene compounds, 3,3a‐dihydrocyclo­penta­[b]chromen‐1(2H)‐one, C₁₆H₁₂O₂, (I), and 2‐(2‐hydroxy­benzyl­idene)‐3,3a‐dihydrocyclo­penta­[b]chromen‐1(2H)‐one, C₁₉H₁₄O₃, (II), have been determined in the monoclinic space group P2₁/n. Compound (I) is mainly stabilized by C—H⋯π inter­actions. Compound (II) is linked into infinite one‐dimensional chains with a C(3) motif via inter­molecular O—H⋯O hydrogen bonds. The inter­molecular C—H⋯π and π–­π inter­actions also play key roles in stabilizing the crystal packing. Two intra­molecular C—H⋯O hydrogen bonds with S(5) motifs were detected in (II).     

N1‐(4‐tert‐Butyl­phenyl)‐N2‐hydroxy‐α‐oxo‐α‐phenyl­acet­amidine and N2‐hydroxy‐N1‐(4‐nitro­phenyl)‐α‐oxo‐α‐phenyl­acet­amidine hemihydrate

In the title compounds, C₁₈H₂₀N₂O₂, (I), and C₁₄H₁₁N₃O₄·0.5H₂O, (II), respectively, the oxime groups have an E configuration. In (I), the mol­ecules exist as polymers bound by intermolecular C—H⋯O and O—H⋯N hydrogen bonds around inversion centres. In (II), intermolecular OW—H⋯N, OW—H⋯O and O—H⋯OW interactions stabilize the molecular packing.     

Supramolecular structures of three isomeric 4‐(methyl­phenylamino)­pyridine‐3‐sulfonamides

The structures of the three title isomers, namely 4‐(2‐methyl­anilino)pyridine‐3‐sulfonamide, (I), 4‐(3‐methyl­anilino)pyridine‐3‐sulfonamide, (II), and 4‐(4‐methyl­anilino)pyridine‐3‐sulfonamide, (III), all C₁₂H₁₃N₃O₂S, differ in their hydrogen‐bonding arrangements. In all three mol­ecules, the conformation of the 4‐amino­pyridine‐3‐sulfon­amide moiety is conserved by an intra­molecular N—H⋯O hydrogen bond and a C—H⋯O inter­action. In the supra­mol­ecular structures of all three isomers, similar C(6) chains are formed via inter­molecular N—H⋯N hydrogen bonds. N—H⋯O hydrogen bonds lead to C(4) chains in (I), and to R₂²(8) centrosymmetric dimers in (II) and (III). In each isomer, the overall effect of all hydrogen bonds is to form layer structures.     

1‐(4,6‐Diethoxy­pyrimidin‐2‐yl)‐2‐thioxo‐2,3‐dihydro­pyrido[2,3‐d]pyrimidin‐4(1H)‐one

In the title compound, C₁₅H₁₅N₅O₃S, two parallel inter­molecular N—H⋯S hydrogen bonds, forming an eight‐membered ring, link two mol­ecules into a dimer unit; these dimer units linked into a chain of edge‐fused rings by weak C—H⋯O hydrogen bonds.     

N‐Benzyl­tetra­hydro­pyrido‐anellated thio­phene derivatives: new anti­cholinesterases

The title compounds, tert‐butyl 6‐benzyl‐2‐(3,3‐diethyl­ureido)‐4,5,6,7‐tetra­hydro­thieno[2,3‐c]pyridine‐3‐carboxyl­ate, C₂₄H₃₃N₃O₃S, (I), 7‐benzyl‐2‐diethyl­amino‐5,6,7,8‐tetra­hydro‐3‐oxa‐9‐thia‐1,7‐diaza­fluoren‐4‐one, C₂₀H₂₃N₃O₂S, (II), and N‐(7‐benzyl‐4‐oxo‐5,6,7,8‐tetra­hydro‐4H‐3,9‐dithia‐1,7‐diaza­fluoren‐2‐yl)benzamide, C₂₃H₁₉N₃O₂S₂, (III), form monoclinic crystal systems. In (I) and (II), the mol­ecules are linked into a three‐dimensional framework by weak inter­molecular C—H⋯O=C hydrogen bonds, whereas in (III) stronger inter­molecular N—H⋯O=C inter­actions are observed. The conformation of (I) is further stabilized by an intra­molecular N—H⋯O=C hydrogen bond, which effects the planarity of the ureido­thio­phene­carboxyl­ate moiety.     

4‐Amino‐5‐(2‐hydroxy‐4,4‐di­methyl‐6‐oxo­cyclo­hexenyl­methyl)‐1‐methyl‐2‐(methyl­sulfanyl)­pyrimidin‐6(1H)‐one: hydrogen‐bonded chains are π‐stacked in pairs

Molecules of the title compound, C₁₅H₂₁N₃O₃S, have a markedly polarized electronic structure; the carbocyclic ring adopts an envelope conformation and the overall molecular conformation appears to be controlled by two intramolecular hydrogen bonds, one each of the O—H⋯O and N—H⋯O types. The mol­ecules are linked into C(6) chains by an intermol­ecular N—H⋯O hydrogen bond, and pairs of these hydrogen‐bonded chains are linked by a π–π stacking interaction.     

2,4,6‐Trimethyl‐N‐nitro­aniline

In 2,4,6‐trimethyl‐N‐nitro­aniline (alternatively called mesitylnitramine), C₉H₁₂N₂O₂, the primary nitramino group is planar with a short N—N bond and is nearly perpendicular to the aromatic ring. The methyl group located in the para position is disordered, each H atom having half‐occupancy. The mol­ecules are linked together along the [100] axis by inter­molecular N—H⋯O hydrogen bonds.     

trans‐Di­aqua­bis­(thio­semicarb­azido‐κ2N,S)­nickel(II) dimaleate dihydrate

In the title compound, [Ni(CH₅N₃S)₂(H₂O)₂](C₄H₃O₄)₂·2H₂O, the Ni atom lies on a center of symmetry and is coordinated by N and S atoms from two thio­semicarbazide ligands and the O atoms of two water mol­ecules in a distorted octahedral geometry. In the asymmetric unit, the three components are linked together by one O—H⋯O and two N—H⋯O hydrogen bonds. The packing is built from molecular ribbons parallel to the b direction, stabilized by intramolecular hydrogen bonds, and by one N—H⋯S and two N—H⋯O intermolecular hydrogen bonds. The ribbons are further connected into columns by N—H⋯O interactions and then into a three‐dimensional network by three O—H⋯O hydrogen bonds.     

Di­aza­bi­cyclo­[2.2.2]­octane‐1,4‐diium dichromate

The title compound, (C₆H₁₄N₂)[Cr₂O₇], consists of a di­aza­bi­cyclo­[2.2.2]­octane‐1,4‐diium cation and a discrete dichromate anion, which are linked in the crystal by N—H⋯O hydrogen bonds. The cation is ordered and distorted, owing to the confinement and twist of the hydrogen bonds involved. Two CrO₄ tetrahedra are joined through a shared O atom to form the dichromate anion. Chiral supramolecular chains of the title compound are built up via N—H⋯O hydrogen bonds, and C—H⋯O interactions play subordinate roles in forming the structure.     

N,N′‐Bis(2‐pyridylmeth­yl)ferrocene‐1,1′‐diyldicarboxamide and N,N′‐bis­(3‐pyridylmeth­yl)ferrocene‐1,1′‐diyldicarboxamide

The mol­ecules of N,N′‐bis­(2‐pyridylmeth­yl)ferrocene‐1,1′‐diyl­dicarboxamide, [Fe(C₁₂H₁₁N₂O)₂], contain intra­molecular N—H⋯N hydrogen bonds and are linked into sheets by three independent C—H⋯O hydrogen bonds. The mol­ecules of the isomeric compound N,N′‐bis­(3‐pyridylmeth­yl)ferrocene‐1,1′‐diyldicarboxamide lie across inversion centres, and the mol­ecules are linked into sheets by a combination of N—H⋯N hydrogen bonds and π–π stacking inter­actions between pyridyl groups.