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).     

Constructor graph description of the hydrogen‐bonding supramolecular assembly in two ionic compounds: 2‐(pyrazol‐1‐yl)ethylammonium chloride and diaquadichloridobis(2‐hydroxyethylammonium)cobalt(II) dichloride

Covalent bond tables are used to generate hydrogen‐bond pattern designator symbols for the crystallographically characterized title compounds. 2‐(Pyrazol‐1‐yl)ethylammonium chloride, C₅H₁₀N₃⁺·Cl⁻, (I), has three unique, strong, charge‐assisted hydrogen bonds of the types N—H...Cl and N—H...N that form unary through ternary levels of graph‐set interactions. Diaquadichloridobis(2‐hydroxyethylammonium)cobalt(II) dichloride, [CoCl₂(C₂H₈NO)₂(H₂O)₂]Cl₂, (II), forms five unique charge‐assisted hydrogen bonds of the types O—H...Cl and N—H...Cl. These form graph‐set patterns up to the quinary level. The Co complex in (II) resides at a crystallographic inversion center; thus the number of hydrogen bonds to consider doubles due to their G‐equivalence, and the handling of such a case is demonstrated.     

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].     

10‐Benzyl‐4‐oxo‐2,3,4,10‐tetrahydropyrimido[4,5‐b]quinolin‐2‐iminium chloride sesquihydrate: a polarized electronic structure within a complex hydrogen‐bonded sheet structure

In the title compound, C₁₈H₁₅N₄O⁺·Cl⁻·1.5H₂O, one water site is fully ordered with unit occupancy while the other, which lies close to an inversion centre in the space group C2/c, has only 0.5 occupancy. The cation exhibits bond fixation in the fused carbocyclic ring and electronic polarization in the terminal heterocyclic ring. The components are linked into complex sheets by a combination of N—H...O, N—H...Cl, O—H...O, O—H...Cl and C—H...O hydrogen bonds.     

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].     

(S)‐5‐Benzylimidazolidine‐2,4‐dione monohydrate

The crystal structure of the title compound, C₁₀H₁₀N₂O₂·H₂O, also known as l ‐5‐benzylhydantoin monohydrate, is described in terms of two‐dimensional supramolecular arrays built up from infinite chains assembled via N—H...O and O—H...O hydrogen bonds among the organic molecules and solvent water molecules, with graph‐set R³₃(10)C(5)C²₂(6). The hydrogen‐bond network is reinforced by stacking of the layers through C—H...π interactions.     

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.     

4‐(3‐Azaniumylpropyl)morpholin‐4‐ium chloride hydrogen oxalate: an unusual example of a dication with different counter‐anions

The mixed organic–inorganic title salt, C₇H₁₈N₂O²⁺·C₂HO₄⁻·Cl⁻, forms an assembly of ionic components which are stabilized through a series of hydrogen bonds and charge‐assisted intermolecular interactions. The title assembly crystallizes in the monoclinic C2/c space group with Z = 8. The asymmetric unit consists of a 4‐(3‐azaniumylpropyl)morpholin‐4‐ium dication, a hydrogen oxalate counter‐anion and an inorganic chloride counter‐anion. The organic cations and anions are connected through a network of N—H...O, O—H...O and C—H...O hydrogen bonds, forming several intermolecular rings that can be described by the graph‐set notations R₃³(13), R₂¹(5), R₁²(5), R₂¹(6), R₂³(6), R₂²(8) and R₃³(9). The 4‐(3‐azaniumylpropyl)morpholin‐4‐ium dications are interconnected through N—H...O hydrogen bonds, forming C(9) chains that run diagonally along the ab face. Furthermore, the hydrogen oxalate anions are interconnected via O—H...O hydrogen bonds, forming head‐to‐tail C(5) chains along the crystallographic b axis. The two types of chains are linked through additional N—H...O and O—H...O hydrogen bonds, and the hydrogen oxalate chains are sandwiched by the 4‐(3‐azaniumylpropyl)morpholin‐4‐ium chains, forming organic layers that are separated by the chloride anions. Finally, the layered three‐dimensional structure is stabilized via intermolecular N—H...Cl and C—H...Cl interactions.     

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).     

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.     

Comparison of the hydrogen‐bond patterns in 2‐amino‐1,3,4‐thiadiazolium hydrogen oxalate, 2‐amino‐1,3,4‐thiadiazole–succinic acid (1/2), 2‐amino‐1,3,4‐thiadiazole–glutaric acid (1/1) and 2‐amino‐1,3,4‐thiadiazole–adipic acid (1/1)

The X‐ray single‐crystal structure determinations of the chemically related compounds 2‐amino‐1,3,4‐thiadiazolium hydrogen oxalate, C₂H₄N₃S⁺·C₂HO₄⁻, (I), 2‐amino‐1,3,4‐thiadiazole–succinic acid (1/2), C₂H₃N₃S·2C₄H₆O₄, (II), 2‐amino‐1,3,4‐thiadiazole–glutaric acid (1/1), C₂H₃N₃S·C₅H₈O₄, (III), and 2‐amino‐1,3,4‐thiadiazole–adipic acid (1/1), C₂H₃N₃S·C₆H₁₀O₄, (IV), are reported and their hydrogen‐bonding patterns are compared. The hydrogen bonds are of the types N—H...O or O—H...N and are of moderate strength. In some cases, weak C—H...O interactions are also present. Compound (II) differs from the others not only in the molar ratio of base and acid (1:2), but also in its hydrogen‐bonding pattern, which is based on chain motifs. In (I), (III) and (IV), the most prominent feature is the presence of an R₂²(8) graph‐set motif formed by N—H...O and O—H...N hydrogen bonds, which are present in all structures except for (I), where only a pair of N—H...O hydrogen bonds is present, in agreement with the greater acidity of oxalic acid. There are nonbonding S...O interactions present in all four structures. The difference electron‐density maps show a lack of electron density about the S atom along the S...O vector. In all four structures, the carboxylic acid H atoms are present in a rare configuration with a C—C—O—H torsion angle of ∼0°. In the structures of (II)–(IV), the C—C—O—H torsion angle of the second carboxylic acid group has the more common value of ∼|180|°. The dicarboxylic acid molecules are situated on crystallographic inversion centres in (II). The Raman and IR spectra of the title compounds are presented and analysed.     

Hydrogen bonding in two ammonium salts of 5‐sulfosalicylic acid: ammonium 3‐carboxy‐4‐hydroxybenzenesulfonate monohydrate and triammonium 3‐carboxy‐4‐hydroxybenzenesulfonate 3‐carboxylato‐4‐hydroxybenzenesulfonate

The structures of two ammonium salts of 3‐carboxy‐4‐hydroxybenzenesulfonic acid (5‐sulfosalicylic acid, 5‐SSA) have been determined at 200 K. In the 1:1 hydrated salt, ammonium 3‐carboxy‐4‐hydroxybenzenesulfonate monohydrate, NH₄⁺·C₇H₅O₆S⁻·H₂O, (I), the 5‐SSA⁻ monoanions give two types of head‐to‐tail laterally linked cyclic hydrogen‐bonding associations, both with graph‐set R₄⁴(20). The first involves both carboxylic acid O—H...O_water and water O—H...O_sulfonate hydrogen bonds at one end, and ammonium N—H...O_sulfonate and N—H...O_carboxy hydrogen bonds at the other. The second association is centrosymmetric, with end linkages through water O—H...O_sulfonate hydrogen bonds. These conjoined units form stacks down c and are extended into a three‐dimensional framework structure through N—H...O and water O—H...O hydrogen bonds to sulfonate O‐atom acceptors. Anhydrous triammonium 3‐carboxy‐4‐hydroxybenzenesulfonate 3‐carboxylato‐4‐hydroxybenzenesulfonate, 3NH₄⁺·C₇H₄O₆S²⁻·C₇H₅O₆S⁻, (II), is unusual, having both dianionic 5‐SSA²⁻ and monoanionic 5‐SSA⁻ species. These are linked by a carboxylic acid O—H...O hydrogen bond and, together with the three ammonium cations (two on general sites and the third comprising two independent half‐cations lying on crystallographic twofold rotation axes), give a pseudo‐centrosymmetric asymmetric unit. Cation–anion hydrogen bonding within this layered unit involves a cyclic R₃³(8) association which, together with extensive peripheral N—H...O hydrogen bonding involving both sulfonate and carboxy/carboxylate acceptors, gives a three‐dimensional framework structure. This work further demonstrates the utility of the 5‐SSA⁻ monoanion for the generation of stable hydrogen‐bonded crystalline materials, and provides the structure of a dianionic 5‐SSA²⁻ species of which there are only a few examples in the crystallographic literature.     

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.     

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.     

Helical supramolecular assembly of N2,N2′‐bis[3‐(morpholin‐4‐yl)propyl]‐N1,N1′‐(1,2‐phenylene)dioxalamide dimethyl sulfoxide monosolvate

In the title compound, C₂₄H₃₆N₆O₆·C₂H₆OS, the carbonyl groups are in an antiperiplanar conformation, with O=C—C=O torsion angles of 178.59 (15) and −172.08 (16)°. An intramolecular hydrogen‐bonding pattern is depicted by four N—H...O interactions, which form two adjacent S(5)S(5) motifs, and an N—H...N interaction, which forms an S(6) ring motif. Intermolecular N—H...O hydrogen bonding and C—H...O soft interactions allow the formation of a meso‐helix. The title compound is the first example of a helical 1,2‐phenylenedioxalamide. The oxalamide traps one molecule of dimethyl sulfoxide through N—H...O hydrogen bonding. C—H...O soft interactions give rise to the two‐dimensional structure.     

Hydrogen‐bonded frameworks of bis(2‐carboxypyridinium) hexafluorosilicate and bis(2‐carboxyquinolinium) hexafluorosilicate dihydrate

In bis(2‐carboxypyridinium) hexafluorosilicate, 2C₆H₆NO₂⁺·SiF₆²⁻, (I), and bis(2‐carboxyquinolinium) hexafluorosilicate dihydrate, 2C₁₀H₈NO₂⁺·SiF₆²⁻·2H₂O, (II), the Si atoms of the anions reside on crystallographic centres of inversion. Primary inter‐ion interactions in (I) occur via strong N—H...F and O—H...F hydrogen bonds, generating corrugated layers incorporating [SiF₆]²⁻ anions as four‐connected net nodes and organic cations as simple links in between. In (II), a set of strong N—H...F, O—H...O and O—H...F hydrogen bonds, involving water molecules, gives a three‐dimensional heterocoordinated rutile‐like framework that integrates [SiF₆]²⁻ anions as six‐connected and water molecules as three‐connected nodes. The carboxyl groups of the cation are hydrogen bonded to the water molecule [O...O = 2.5533 (13) Å], while the N—H group supports direct bonding to the anion [N...F = 2.7061 (12) Å].     

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.     

2,5‐Dicarboxy­anilinium chloride monohydrate

The title compound, C₈H₈NO₄⁺·Cl⁻·H₂O, is the chloro­hydrated form of 2‐amino­benzene‐1,4‐dicarboxylic acid, the basic crystal structure of which is still not known. Mol­ecules are linked by classical N—H⋯O, O—H⋯O, N—H⋯Cl and O—H⋯Cl hydrogen bonds, mainly along the mol­ecular plane, into sheets built by unusual R₆⁴(26), R₆⁴(22) and R₄³(22) rings. The stacking between layers is stabilized by another N—H⋯Cl hydrogen bond and by π–π inter­actions between aromatic rings facing each other.