Constructor graph description of hydrogen bonding in a supramolecular assembly of (3,5‐dimethyl‐1H‐pyrazol‐4‐ylmethyl)isopropylammonium chloride monohydrate

Five distinct strong hydrogen‐bonding interactions of four kinds (N—H...Cl, N—H...O, O—H...N, and O—H...Cl) connect molecules of the title compound, C₉H₁₈N₃⁺·Cl⁻·H₂O, in the crystal structure into corrugated sheets stacked along the a axis. The intermolecular interactions are efficiently described in terms of the first‐ through fifth‐level graph sets. A two‐dimensional constructor graph helps visualize the supramolecular assembly.     

Hydrogen‐bonding patterns in bis[2,4,6‐triazaniumylcyclohexane‐1,3,5‐tris(olate)‐κ3O,O′,O′′]germanium(IV) tetrachloride hexahydrate

A first preliminary report on the crystal structure of a hydrated salt formulated as [Ge(taci)₂]Cl₄·13H₂O (taci is 1,3,5‐triamino‐1,3,5‐trideoxy‐cis‐inositol) appeared more than 20 years ago [Ghisletta (1994). PhD thesis, ETH Zürich. Switzerland]. At that time it was not possible to discriminate unambiguously between the positions of some of the chloride ions and water O atoms, and disorder was thus postulated. In a new determination, a conclusive scheme of hydrogen bonding proves to be a particularly appealing aspect of the structure. Single crystals of the title compound, C₁₂H₃₀GeN₆O₆⁴⁺·4Cl⁻·6H₂O or [Ge(taci)₂]₂Cl₈·12H₂O, were grown from an aqueous solution by slow evaporation of the solvent. The two [Ge(taci)₂]⁴⁺ cations exhibit a double‐adamantane‐type structure with exclusive O‐atom coordination and approximate D_3d symmetry. The taci ligands adopt a zwitterionic form with deprotonated hydroxy groups and protonated amino groups. Both cations are hydrogen bonded to six water molecules. The structure of the hydration shell of the two cations is, however, slightly different. The {[Ge(taci)₂]·6H₂O}⁴⁺ aggregates are interlinked in all three dimensions by further hydrogen bonds of the types N—H...Cl...H—N, N—H...O(H)₂...H—N, (Ge)O...H—O(H)...H—N, N—H...O(H)—H...Cl...H—N, (Ge)O...H—O—H...Cl...H—N, N—H...O(H)—H...Cl...H—(H)O...H—N, (Ge)O...H—O—H...Cl...H—(H)O...H—N and Ge(O)...H—O—H...Cl...H—O—H...O(Ge).     

(R)‐4‐(4‐Fluoro­phenyl)‐1‐[2‐hydroxy‐2‐(3‐methyl‐1‐benzo­furan‐2‐yl)­ethyl]­piperazinium chloride propan‐1‐ol solvate

The title compound, C₂₁H₂₄FN₂O₂⁺·Cl⁻·C₃H₈O, is a potential drug designed as a hybrid compound with antihypertensive, antioxidant and β‐adrenolytic activity. The cation contains nearly planar benzo­furan and fluoro­phenyl ring systems, as well as a piperazine ring adopting an almost perfect chair conformation. The benzo­furan and piperazine moieties are connected by an ethyl chain, the moieties forming a dihedral angle of 163.12 (13)°. In the crystal structure, ions and propanol solvent mol­ecules are linked via N—H⋯Cl and O—H⋯Cl bonds into linear (010) chains.     

Bis(adamantan‐1‐aminium) tetrachloridozincate(II) 18‐crown‐6 monohydrate clathrate

The structure of the title compound [systematic name: bis(adamantan‐1‐aminium) tetrachloridozincate(II)–1,4,7,10,13,16‐hexaoxacyclooctadecane–water (1/1/1)], (C₁₀H₁₈N)₂[ZnCl₄]·C₁₂H₂₄O₆·H₂O, consists of supramolecular rotator–stator assemblies and ribbons of hydrogen bonds parallel to [010]. The assemblies are composed of one protonated adamantan‐1‐aminium cation and one crown ether molecule (1,4,7,10,13,16‐hexaoxacyclooctadecane) to give an overall [(C₁₀H₁₈N)(18‐crown‐6)]⁺ cation. The –NH₃⁺ group of the cation nests in the crown and links to the crown‐ether O atoms through N—H...O hydrogen bonds. The 18‐crown‐6 ring adopts a pseudo‐C_3v conformation. The second adamantan‐1‐aminium forms part of ribbons of adamantan‐1‐aminium–water–tetrachloridozincate units which are interconnected by O—H...Cl, N—H...O and N—H...Cl hydrogen bonds via three different continuous rings with R₅⁴(12), R₄³(10) and R₃³(8) motifs.     

2‐Ethyl‐6‐methylpyridin‐3‐ol and its salt bis(2‐ethyl‐3‐hydroxy‐6‐methylpyridinium) succinate

The title compounds, C₈H₁₁NO, (I), and 2C₈H₁₂NO⁺·C₄H₄O₄²⁻, (II), both crystallize in the monoclinic space group P2₁/c. In the crystal structure of (I), intermolecular O—H...N hydrogen bonds combine the molecules into polymeric chains extending along the c axis. The chains are linked by C—H...π interactions between the methylene H atoms and the pyridine rings into polymeric layers parallel to the ac plane. In the crystal structure of (II), the succinate anion lies on an inversion centre. Its carboxylate groups interact with the 2‐ethyl‐3‐hydroxy‐6‐methylpyridinium cations via intermolecular N—H...O hydrogen bonds with the pyridine ring H atoms and O—H...O hydrogen bonds with the hydroxy H atoms to form polymeric chains, which extend along the [01] direction and comprise R₄⁴(18) hydrogen‐bonded ring motifs. These chains are linked to form a three‐dimensional network through nonclassical C—H...O hydrogen bonds between the pyridine ring H atoms and the hydroxy‐group O atoms of neighbouring cations. π–π interactions between the pyridine rings and C—H...π interactions between the methylene H atoms of the succinate anion and the pyridine rings are also present in this network.     

1‐Carboxymethyl‐3‐methyl‐1H‐imidazol‐3‐ium chloride 2‐(3‐methyl‐1H‐imidazol‐3‐ium‐1‐yl)acetate monohydrate: a crystal stabilized by imidazolium zwitterions

The title compound, C₆H₉N₂O₂⁺·Cl⁻·C₆H₈N₂O₂·H₂O, contains one 2‐(3‐methyl‐1H‐imidazol‐3‐ium‐1‐yl)acetate inner salt molecule, one 1‐carboxymethyl‐3‐methyl‐1H‐imidazol‐3‐ium cation, one chloride ion and one water molecule. In the extended structure, chloride anions and water molecules are linked via O—H...Cl hydrogen bonds, forming an infinite one‐dimensional chain. The chloride anions are also linked by two weak C—H...Cl interactions to neighbouring methylene groups and imidazole rings. Two imidazolium moieties form a homoconjugated cation through a strong and asymmetric O—H...O hydrogen bond of 2.472 (2) Å. The IR spectrum shows a continuous D‐type absorption in the region below 1300 cm⁻¹ and is different to that of 1‐carboxymethyl‐3‐methylimidazolium chloride [Xuan, Wang & Xue (2012). Spectrochim. Acta Part A, 96 , 436–443].     

N,N′‐Bis(2‐hydroxycyclohexyl)‐N,N′‐bis(2‐hydroxyethyl)ethane‐1,2‐diaminium dichloride

The achiral meso form of the title compound, C₁₈H₃₈N₂O₄²⁺·2Cl⁻, crystallizes to form undulating layers consisting of chains linked via weak hydroxyalkyl C—H...Cl contacts. The chains are characterized by centrosymmetric hydrogen‐bonded dimers generated via N—H...Cl and hydroxycycloalkyl O—H...Cl interactions. trans‐N‐Alkyl bridges subdivide the chains into hydrophilic segments flanked by hydrophobic cycloalkyl stacks along [001].     

(Z)‐5‐[(5‐Methyl‐1H‐imidazol‐4‐yl)methylidene]‐2‐sulfanylidene‐1,3‐thiazolidin‐4‐one monohydrate: a three‐dimensional hydrogen‐bonded framework structure

The non‐H atoms in the organic component of the title compound, C₈H₇N₃OS₂·H₂O, are almost coplanar, as the dihedral angle between the two ring planes is only 1.8 (2)°; there is a wide C—C—C angle of 127.8 (3)° at the methine C atom linking the two rings. The molecular components are linked into a three‐dimensional framework structure by two‐centre hydrogen bonds of N—H...O and O—H...N types, together with a three‐centre O—H...(N,S) system. Comparisons are made with some (Z)‐5‐arylmethylidene‐2‐sulfanylidene‐1,3‐thiazolidin‐4‐ones.     

Supramolecular interactions in carboxylate and sulfonate salts of 2,6‐diamino‐4‐chloropyrimidinium

Two new salts, namely 2,6‐diamino‐4‐chloropyrimidinium 2‐carboxy‐3‐nitrobenzoate, C₄H₆ClN₄⁺·C₈H₄NO₆⁻, (I), and 2,6‐diamino‐4‐chloropyrimidinium p‐toluenesulfonate monohydrate, C₄H₆ClN₄⁺·C₇H₇O₃S⁻·H₂O, (II), have been synthesized and characterized by single‐crystal X‐ray diffraction. In both crystal structures, the N atom in the 1‐position of the pyrimidine ring is protonated. In salt (I), the protonated N atom and the amino group of the pyrimidinium cation interact with the carboxylate group of the anion through N—H…O hydrogen bonds to form a heterosynthon with an R ₂²(8) ring motif. In hydrated salt (II), the presence of the water molecule prevents the formation of the familiar R ₂²(8) ring motif. Instead, an expanded ring [i.e. R ₃²(8)] is formed involving the sulfonate group, the pyrimidinium cation and the water molecule. Both salts form a supramolecular homosynthon [R ₂²(8) ring motif] through N—H…N hydrogen bonds. The molecular structures are further stabilized by π–π stacking, and C=O…π, C—H…O and C—H…Cl interactions.     

The inner‐salt zwitterion,the dihydrochloride dihydrate and the dimethyl sulfoxide disolvate of 3,6‐bis(pyridin‐2‐yl)pyrazine‐2,5‐dicarboxylic acid

In the inner‐salt zwitterion of 3,6‐bis(pyridin‐2‐yl)pyrazine‐2,5‐dicarboxylic acid, (I), namely 5‐carboxy‐3‐(pyridin‐1‐ium‐2‐yl)‐6‐(pyridin‐2‐yl)pyrazine‐2‐carboxylate, [C₁₆H₁₀N₄O₄, (Ia)], the pyrazine ring has a twist–boat conformation. The opposing pyridine and pyridinium rings are almost perpendicular to one another, with a dihedral angle of 80.24 (18)°, and are inclined to the pyrazine mean plane by 36.83 (17) and 43.74 (17)°, respectively. The carboxy and carboxylate groups are inclined to the mean plane of the pyrazine ring by 43.60 (17) and 45.46 (17)°, respectively. In the crystal structure, the molecules are linked via N—H...O and O—H...O hydrogen bonds, leading to the formation of double‐stranded chains propagating in the [010] direction. On treating (Ia) with aqueous 1 M HCl, the diprotonated dihydrate form 2,2′‐(3,6‐dicarboxypyrazine‐2,5‐diyl)bis(pyridin‐1‐ium) dichloride dihydrate [C₁₆H₁₂N₄O₄²⁺·2Cl⁻·2H₂O, (Ib)] was obtained. The cation lies about an inversion centre. The pyridinium rings and carboxy groups are inclined to the planar pyrazine ring by 55.53 (9) and 19.8 (2)°, respectively. In the crystal structure, the molecules are involved in N—H...Cl, O—H...O_water and O_water—H...Cl hydrogen bonds, leading to the formation of chains propagating in the [010] direction. When (Ia) was recrystallized from dimethyl sulfoxide (DMSO), the DMSO disolvate 3,6‐bis(pyridin‐2‐yl)pyrazine‐2,5‐dicarboxylic acid dimethyl sulfoxide disolvate [C₁₆H₁₀N₄O₄·2C₂H₆OS, (Ic)] of (I) was obtained. Here, the molecule of (I) lies about an inversion centre and the pyridine rings are inclined to the planar pyrazine ring by only 23.59 (12)°. However, the carboxy groups are inclined to the pyrazine ring by 69.0 (3)°. In the crystal structure, the carboxy groups are linked to the DMSO molecules by O—H...O hydrogen bonds. In all three crystal structures, the presence of nonclassical hydrogen bonds gives rise to the formation of three‐dimensional supramolecular architectures.     

Supramolecular hydrogen‐bonding patterns in two cocrystals of the N(7)–H tautomeric form of N6‐benzoyladenine: N6‐benzoyladenine–3‐hydroxypyridinium‐2‐carboxylate (1/1) and N6‐benzoyladenine–DL‐tartaric acid (1/1)

Two novel cocrystals of the N(7)—H tautomeric form of N⁶‐benzoyladenine (BA), namely N⁶‐benzoyladenine–3‐hydroxypyridinium‐2‐carboxylate (3HPA) (1/1), C₁₂H₉N₅O·C₆H₅NO₃, (I), and N⁶‐benzoyladenine–DL‐tartaric acid (TA) (1/1), C₁₂H₉N₅O·C₄H₆O₆, (II), are reported. In both cocrystals, the N⁶‐benzoyladenine molecule exists as the N(7)—H tautomer, and this tautomeric form is stabilized by intramolecular N—H...O hydrogen bonding between the benzoyl C=O group and the N(7)—H hydrogen on the Hoogsteen site of the purine ring, forming an S(7) motif. The dihedral angle between the adenine and phenyl planes is 0.94 (8)° in (I) and 9.77 (8)° in (II). In (I), the Watson–Crick face of BA (N6—H and N1; purine numbering) interacts with the carboxylate and phenol groups of 3HPA through N—H...O and O—H...N hydrogen bonds, generating a ring‐motif heterosynthon [graph set R₂²(6)]. However, in (II), the Hoogsteen face of BA (benzoyl O atom and N7; purine numbering) interacts with TA (hydroxy and carbonyl O atoms) through N—H...O and O—H...O hydrogen bonds, generating a different heterosynthon [graph set R₂²(4)]. Both crystal structures are further stabilized by π–π stacking interactions.     

Polymorphism in 2‐(4‐hydroxy‐2,6‐dimethylanilino)‐5,6‐dihydro‐4H‐1,3‐thiazin‐3‐ium chloride

Details of the structures of two conformational polymorphs of the title compound, C₁₂H₁₇N₂OS⁺·Cl⁻, are reported. In form (I) (space group P), the two N—H groups of the cation are in a trans conformation, while in form (II) (space group P2₁/c), they are in a cis arrangement. This results in different packing and hydrogen‐bond arrangements in the two forms, both of which have extended chains lying along the a direction. In form (I), these chains are composed of centrosymmetric R₄²(18) (N—H...Cl and O—H...Cl) hydrogen‐bonded rings and R₂²(18) (N—H...O) hydrogen‐bonded rings. In form (II), the chains are formed by centrosymmetric R₄²(18) (N—H...Cl and O—H...Cl) hydrogen‐bonded rings and by R₄²(12) (N—H...Cl) hydrogen‐bonded rings.     

Three‐dimensional networks in bis(imidazolium) 2,2′‐dithiodibenzoate and 4‐methylimidazolium 2‐[(2‐carboxyphenyl)disulfanyl]benzoate

Cocrystallization of imidazole or 4‐methylimidazole with 2,2′‐dithiodibenzoic acid from methanol solution yields the title 2:1 and 1:1 organic salts, 2C₃H₅N₂⁺·C₁₄H₁₀O₄S₂²⁻, (I), and C₄H₇N₂⁺·C₁₄H₁₀O₄S₂⁻, (II), respectively. Compound (I) crystallizes in the monoclinic C2/c space group with the mid‐point of the S—S bond lying on a twofold axis. The component ions in (I) are linked by intermolecular N—H...O hydrogen bonds to form a two‐dimensional network, which is further linked by C—H...O hydrogen bonds into a three‐dimensional network. In contrast, by means of N—H...O, N—H...S and O—H...O hydrogen bonds, the component ions in (II) are linked into a tape and adjacent tapes are further linked by π–π, C—H...O and C—H...π interactions, resulting in a three‐dimensional network.     

1‐Methyl‐4‐nitraminopyridinium nitrate and 4‐nitraminopyridinium methanesulfonate

In the title compounds, C₆H₈N₃O₂⁺·NO₃^? and C₅­H₆­N₃­O₂⁺·­CH₃SO₃^?, respectively, the cations are almost planar; the twist of the nitr­amino group about the C—N and N—N bonds does not exceed 10°. The deviations from coplanarity are accounted for by intermolecular N—H?O interactions. The coplanarity of the NHNO₂ group and the phenyl ring leads to the deformation of the nitr­amino group. The C—N—N angle and one C—C—N angle at the junction of the phenyl ring and the nitr­amino group are increased from 120° by ca 6°, whereas the other junction C—C—N angle is decreased by ca 5°. Within the nitro group, the O—N—O angle is increased by ca 5° and one O—N—N angle is decreased by ca 5°, whereas the other O—N—N angle remains almost unchanged. The cations are connected to the anions by relatively strong N—H?O hydrogen bonds [shortest H?O separations 1.77 (2)–1.81 (3) Å] and much weaker C—H?O hydrogen bonds [H?O separations 2.30 (2)–2.63 (3) Å].     

Three‐dimensional hydrogen‐bonded framework in bis(melamin‐1‐ium) naphthalene‐1,5‐disulfonate melamine pentahydrate

Crystals of the title compound, 2C₃H₇N₆⁺·C₁₀H₆O₆S₂²⁻·C₃H₆N₆·5H₂O, are built up of neutral 2,4,6‐triamino‐1,3,5‐triazine (melamine), singly protonated melaminium cations, naphthalene‐1,5‐disulfonate dianions and water molecules. Two independent anions lie across centres of inversion in the space group P. The melamine molecules are connected by N—H...N hydrogen bonds into two different one‐dimensional polymers almost parallel to the (010) plane, forming a stacking structure along the b axis. The centrosymmetric naphthalene‐1,5‐disulfonate anions interact with water molecules via O—H...O hydrogen bonds, forming layers parallel to the (001) plane. The cations and anions are connected by N—H...O and O—H...N hydrogen bonds to form a three‐dimensional supramolecular framework.     

Z and E isomers of butenedioic acid with 2‐amino‐1,3‐thiazole: 2‐amino‐1,3‐thiazolium hydrogen maleate and 2‐amino‐1,3‐thiazolium hydrogen fumarate

Maleic acid and fumaric acid, the Z and E isomers of butenedioic acid, form 1:1 adducts with 2‐amino‐1,3‐thiazole, namely 2‐amino‐1,3‐thiazolium hydrogen maleate (2ATHM), C₃H₅N₂S⁺·C₄H₃O₄⁻, and 2‐amino‐1,3‐thiazolium hydrogen fumarate (2ATHF), C₃H₅N₂S⁺·C₄H₃O₄⁻, respectively. In both compounds, protonation of the ring N atom of the 2‐amino‐1,3‐thiazole and deprotonation of one of the carboxyl groups are observed. The asymmetric unit of 2ATHF contains three independent ion pairs. The hydrogen maleate ion of 2ATHM shows a short intramolecular O—H...O hydrogen bond with an O...O distance of 2.4663 (19) Å. An extensive hydrogen‐bonded network is observed in both compounds, involving N—H...O and O—H...O hydrogen bonds. 2ATHM forms two‐dimensional sheets parallel to the ab plane, extending as independent parallel sheets along the c axis, whereas 2ATHF forms two‐dimensional zigzag layers parallel to the bc plane, extending as independent parallel layers along the a axis.     

(R)‐N‐[(R)‐1‐(2‐Hydroxy‐5‐methyl­phenyl)‐2‐phenyl­ethyl]‐2‐methyl‐1‐phenyl­propyl­ammonium chloride

In the title compound, C₂₅H₃₀NO⁺·Cl⁻, the mol­ecules are linked by a combination of inter­molecular N—H⋯Cl and O—H⋯Cl hydrogen bonds and intra­molecular N—H⋯O hydrogen bonds. The absolute configuration of the new stereogenic centre (the C atom adjacent to the N atom on the phenol side) is determined to have an R configuration.     

Hydrogen‐bond‐directed supramolecular arrays in 4,4′‐bipyridinium tetrachloroterephthalate dihydrate and bis(1,10‐phenanthrolinium) tetrachloroterephthalate tetrachloroterephthalic acid trihydrate

The title compounds, C₁₀H₁₀N₂²⁺·C₈Cl₄O₄²⁻·2H₂O, (I), and 2C₁₂H₉N₂⁺·C₈Cl₄O₄²⁻·C₈H₂Cl₄O₄·3H₂O, (II), both crystallize as charge‐transfer organic salts with the dianionic or neutral acid components lying on inversion centres. The acid and base subunits in (I) arrange alternately to generate a linear tape motif via N—H...O hydrogen bonds; these tapes are further combined into a three‐dimensional architecture through multiple O—H...O and C—H...O interactions involving solvent water molecules. In contrast, the neutral and anionic acid components in (II) are linked to form a zigzag chain by means of O—H...O hydrogen bonds between acid groups, with dangling 1,10‐phenanthrolinium units connected to these chains by carboxylate–pyridinium interactions with R₂²(7) hydrogen‐bond notation. Adjacent chains are further extended to result in a two‐dimensional corrugated layer network viaπ–π interactions. Inter‐ion Cl...O interactions are also found in both (I) and (II).     

4‐Amino‐N‐isopropyl­benzamidinium chloride ethanol solvate

The title compound, C₁₀H₁₆N·Cl⁻·C₂H₆O, is an important intermediate in the convergent synthesis of amidine‐substituted polycyclic heterocycles, a class of compounds that shows significant anticancer activity. The molecule of (I) is not planar, having a dihedral angle of 25.00 (7)° between the aniline and amidine (–C—NH=C=NH₂) groups. The proton­ation of the amidine molecular fragment is accompanied by delocalized C—N bond distances of 1.320 (2) and 1.317 (2) Å. The cations and chloride anions are involved in a network of hydrogen bonds, resulting in the formation of infinite chains propagating along the b direction. The chains are further grouped within the ab plane, in such a way that the structure is segregated into layers dominated by hydro­phobic interactions involving N‐isopropyl residues and layers dominated by N—H⋯Cl [N⋯Cl = 3.275 (2)–3.596 (2) Å], O—H⋯Cl [O⋯Cl = 3.229 (3) Å] and N—H⋯O [N⋯O = 2.965 (3) Å] hydrogen bonds.