The chloride,bromide and iodide salts of 1‐(diaminomethylene)thiouron‐1‐ium

Crystals of 1‐(diaminomethylene)thiouron‐1‐ium chloride, C₂H₇N₄S⁺·Cl⁻, 1‐(diaminomethylene)thiouron‐1‐ium bromide, C₂H₇N₄S⁺·Br⁻, and 1‐(diaminomethylene)thiouron‐1‐ium iodide, C₂H₇N₄S⁺·I⁻, are built up from the nonplanar 1‐(diaminomethylene)thiouron‐1‐ium cation and the respective halogenide anion. The conformation of the 1‐(diaminomethylene)thiouron‐1‐ium cation in each case is twisted. Both arms of the cation are planar and rotated in opposite directions around the C—N bonds involving the central N atom. The dihedral angles describing the twisted conformation are 22.9 (1), 15.2 (1) and 4.2 (1)° in the chloride, bromide and iodide salts, respectively. Ionic and extensive hydrogen‐bonding interactions join oppositely charged units into a supramolecular network. The aim of the investigation is to study the influence of the size of the ionic radii of the Cl⁻, Br⁻ and I⁻ ions on the dimensionality of the hydrogen‐bonding network of the 1‐(diaminomethylene)thiouron‐1‐ium cation. The 1‐(diaminomethylene)thiouron‐1‐ium system should be of use in crystal engineering to form multidimensional networks.     

Hydrogen‐bonded sheets in 2‐(2‐aminophenyl)‐1H‐benzimidazol‐3‐ium dihydrogen phosphate

The title salt, C₁₃H₁₂N₃⁺·H₂PO₄⁻, contains a nonplanar 2‐(2‐aminophenyl)‐1H‐benzimidazol‐3‐ium cation and two different dihydrogen phosphate anions, both situated on twofold rotation axes in the space group C2. The anions are linked by O—H...O hydrogen bonds into chains of R₂²(8) rings. The anion chains are linked by the cations, via hydrogen‐bonding complementarities and electrostatic interactions, giving rise to a sheet structure with alternating rows of organic cations and inorganic anions. Comparison of this structure with that of the pure amine reveals that the two compounds generate characteristically different sheet structures. The anion–anion chain serves as a template for the assembly of the cations, suggesting a possible application in the design of solid‐state materials.     

Hydrogen‐bonded networks in 1‐(4‐methoxyphenyl)‐2,2‐dimethylpropan‐1‐ol

The asymmetric unit of the title compound, C₁₂H₁₈O₂, contains two independent molecules. They differ only slightly in conformation but form completely different intermolecular hydrogen‐bonded arrays. One molecule exhibits disorder in the hydroxy group region, but this does not influence the formation of hydrogen bonds. The bulky tert‐butyl group on one side of the carbinol C atom and the benzene ring on the other side promote the formation of discrete dimeric motifs via hydrogen‐bridged hydroxy groups. Dimers are further joined by strong hydroxy–methoxy O—H...O bonds to form chains with dangling alcohol groups. Weaker intermolecular C—H...O interactions mediate the formation of a two‐dimensional network.     

Hydrogen‐bonded molecular ladders in S‐(4‐nitrophenyl)thioglycolic acid

Molecules of the title compound, [(4‐nitro­phenyl)­sulfanyl]­acetic acid, C₈H₇NO₄S, are linked by paired O—H?O hydrogen bonds [H?O 1.81 Å, O?O 2.6456 (15) Å and O—H?O 178°] into centrosymmetric dimers containing an R(8) motif. A single C—H?O hydrogen bond having a nitro O atom as acceptor [H?O 2.47 Å, 3.3018 (19) Å and C—H?O 147°] links the dimers into a molecular ladder, and neighbouring ladders are weakly linked into sheets by aromatic π–π‐stacking interactions.     

A dihydrogen phosphate anionic network as a host lattice for cations in 1‐methylpiperazine‐1,4‐diium bis(dihydrogen phosphate) and 2‐(pyridin‐2‐yl)pyridinium dihydrogen phosphate–orthophosphoric acid (1/1)

In the salt 1‐methylpiperazine‐1,4‐diium bis(dihydrogen phosphate), C₅H₁₃N₂²⁺·2H₂PO₄⁻, (I), and the solvated salt 2‐(pyridin‐2‐yl)pyridinium dihydrogen phosphate–orthophosphoric acid (1/1), C₁₀H₉N₂⁺·H₂PO₄⁻·H₃PO₄, (II), the formation of O—H...O and N—H...O hydrogen bonds between the dihydrogen phosphate (H₂PO₄⁻) anions and the cations constructs a three‐ and two‐dimensional anionic–cationic network, respectively. In (I), the self‐assembly of H₂PO₄⁻ anions forms a two‐dimensional pseudo‐honeycomb‐like supramolecular architecture along the (010) plane. 1‐Methylpiperazine‐1,4‐diium cations are trapped between the (010) anionic layers through three N—H...O hydrogen bonds. In solvated salt (II), the self‐assembly of H₂PO₄⁻ anions forms a two‐dimensional supramolecular architecture with open channels projecting along the [001] direction. The 2‐(pyridin‐2‐yl)pyridinium cations are trapped between the open channels by N—H...O and C—H...O hydrogen bonds. From a study of previously reported structures, dihydrogen phosphate anions show a supramolecular flexibility depending on the nature of the cations. The dihydrogen phosphate anion may be suitable for the design of the host lattice for host–guest supramolecular systems.     

Hydrogen‐bonded networks in trans‐3‐(3‐pyridyl)acrylic acid and rctt‐3,3′‐(3,4‐dicarboxycyclobutane‐1,2‐diyl)dipyridinium dichloride

The structure of trans‐3‐(3‐pyridyl)acrylic acid, C₈H₇NO₂, (I), possesses a two‐dimensional hydrogen‐bonded array of supramolecular ribbons assembled via heterodimeric synthons between the pyridine and carboxyl groups. This compound is photoreactive in the solid state as a result of close contacts between the double bonds of neighbouring molecules [3.821 (1) Å] along the a axis. The crystal structure of the photoproduct, rctt‐3,3′‐(3,4‐dicarboxycyclobutane‐1,2‐diyl)dipyridinium dichloride, C₁₆H₁₆N₂O₄²⁺·2Cl⁻, (II), consists of a three‐dimensional hydrogen‐bonded network built from crosslinking of helical chains integrated by self‐assembly of dipyridinium cations and Cl⁻ anions via different O—H...Cl, C—H...Cl and N⁺—H...Cl hydrogen‐bond interactions.     

4‐(3,5‐Dimethyl‐1H‐pyrazol‐4‐ylmethyl)‐3,5‐dimethyl‐1H‐pyrazol‐2‐ium dihydrogen phosphate: a combined X‐ray and DFT study

The molecular structure of the title salt, C₁₁H₁₇N₄⁺·H₂PO₄⁻, has been determined from single‐crystal X‐ray analysis and compared with the structure calculated by density functional theory (DFT) at the BLYP level. The crystal packing in the title compound is stabilized primarily by intermolecular N—H...O, O—H...N and O—H...O hydrogen bonds and π–π stacking interactions, and thus a three‐dimensional supramolecular honeycomb network consisting of R₄²(10), R₄⁴(14) and R₄⁴(24) ring motifs is established. The HOMO–LUMO energy gap (1.338 eV; HOMO is the highest occupied molecular orbital and LUMO is the lowest unoccupied molecular orbital) indicates a high chemical reactivity for the title compound.     

Hydrogen‐bonded 1:1 adduct of 1,1′‐(p‐phenylene)dipyridin‐4(1H)‐one with terephthalic acid

Cocrystallization of 1,1′‐(p‐phenylene)dipyridin‐4(1H)‐one (4,4′‐dpy) and terephthalic acid (tpa) affords the hydrogen‐bonded 1:1 title complex, C₁₆H₁₂N₂O₂·C₈H₆O₄. Both mol­ecules are symmetrically disposed about independent symmetry centers. Strong O—H⋯O hydrogen bonds between tpa carboxyl groups and 4,4′‐dpy carbonyl groups produce one‐dimensional zigzag infinite chains. Each chain is linked to four surrounding chains via weak C—H⋯O inter­actions, resulting in a three‐dimensional mol­ecular framework.     

Hydrogen‐bonded sheets in benzylmethylammonium hydrogen maleate

In the title compound, C₈H₁₂N⁺·C₄H₃O₄⁻, there is a short and almost linear but asymmetric O—H...O hydrogen bond in the anion. The ions are linked into C₂²(6) chains by two short and nearly linear N—H...O hydrogen bonds and the chains are further weakly linked into sheets by a single C—H...O hydrogen bond.     

2‐[6‐(1H‐Benzimidazol‐2‐yl)‐2‐pyridyl]‐1H‐benzimidazol‐3‐ium perchlorate monohydrate

The title compound, C₁₉H₁₄N₅⁺·ClO₄^?·H₂O, contains planar C₁₉H₁₄N₅⁺ cations, perchlorate anions and water mol­ecules. The two closest parallel cations (plane‐to‐plane distance of 3.41 Å), together with two neighbouring perchlorate anions and two water mol­ecules, form an electrically neutral quasi‐dimeric unit. Two acidic H atoms of the cation, both H atoms of the water mol­ecule, the N atoms of the imidazole rings and three of the four O atoms of the perchlorate anion are involved in the hydrogen‐bonding network within the dimeric unit. The remaining third acidic H atom of the imidazole rings and the water mol­ecules complete a two‐dimensional network of hydrogen bonds, thus forming puckered layers of dimers. The angle between the planes of two neighbouring dimeric units in the same layer is 33.25 (3)°.     

Hydrogen‐bonded sheet structures in methyl 4‐(4‐chloroanilino)‐3‐nitrobenzoate and methyl 1‐benzyl‐2‐(4‐chlorophenyl)‐1H‐benzimidazole‐5‐carboxylate

In methyl 4‐(4‐chloroanilino)‐3‐nitrobenzoate, C₁₄H₁₁ClN₂O₄, (I), there is an intramolecular N—H...O hydrogen bond and the intramolecular distances provide evidence for electronic polarization of the o‐quinonoid type. The molecules are linked into sheets built from N—H...O, C—H...O and C—H...π(arene) hydrogen bonds, together with an aromatic π–π stacking interaction. The molecules of methyl 1‐benzyl‐2‐(4‐chlorophenyl)‐1H‐benzimidazole‐5‐carboxylate, C₂₂H₁₇ClN₂O₂, (II), are also linked into sheets, this time by a combination of C—H...π(arene) hydrogen bonds and aromatic π–π stacking interactions.     

Hydrogen‐bonded chains of rings in 1‐(4‐chloroanilinomethyl)‐5‐(4‐chlorophenyl)‐1,3,5‐triazinane‐2‐thione and hydrogen‐bonded sheets in 1‐anilinomethyl‐5‐phenyl‐1,3,5‐triazinane‐2‐thione

In 1‐(4‐chloroanilinomethyl)‐5‐(4‐chlorophenyl)‐1,3,5‐triazinane‐2‐thione, C₁₆H₁₆Cl₂N₄S, there are two independent molecules in the asymmetric unit which form inversion dimers via two weak N—H...S hydrogen bonds. The dimers are then linked into C(9)C(14) chains by a C—H...S hydrogen bond and a C—H...Cl contact. In 1‐(anilinomethyl)‐5‐phenyl‐1,3,5‐triazinane‐2‐thione, C₁₆H₁₈N₄S, molecules are linked into complex sheets via a combination of N—H...S and C—H...π hydrogen bonds.     

Hydrogen‐bonded sheet structures in neutral,anionic and hydrated 6‐amino‐2‐(morpholin‐4‐yl)‐5‐nitrosopyrimidines

In each of 6‐amino‐3‐methyl‐2‐(morpholin‐4‐yl)‐5‐nitrosopyrimidin‐4(3H)‐one, C₉H₁₃N₅O₃, (I), morpholin‐4‐ium 4‐amino‐2‐(morpholin‐4‐yl)‐5‐nitroso‐6‐oxo‐1,6‐dihydropyrimidin‐1‐ide, C₄H₁₀NO⁺·C₈H₁₀N₅O₃⁻, (II), and 6‐amino‐2‐(morpholin‐4‐yl)‐5‐nitrosopyrimidin‐4(3H)‐one hemihydrate, C₈H₁₁N₅O₃·0.5H₂O, (III), the bond distances within the pyrimidine components are consistent with significant electronic polarization, which is most marked in (II) and least marked in (I). Despite the high level of substitution, the pyrimidine rings are all effectively planar, and in each of the pyrimidine components, there are intramolecular N—H...O hydrogen bonds. In each compound, the organic components are linked by multiple N—H...O hydrogen bonds to form sheets of widely differing construction, and in compound (III) adjacent sheets are linked by the water molecules, so forming a three‐dimensional hydrogen‐bonded framework. This study also contains the first direct geometric comparison between the electronic polarization in a neutral aminonitrosopyrimidine and that in its ring‐deprotonated conjugate anion in a metal‐free environment.     

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.     

Hydrogen‐bonded structures of the isomeric 2‐, 3‐ and 4‐carbamoylpyridinium hydrogen chloranilates

In the three isomeric salts, all C₆H₇N₂O⁺·C₆HCl₂O₄⁻, of chloranilic acid (2,5‐dichloro‐3,6‐dihydroxy‐1,4‐benzoquinone) with 2‐, 3‐ and 4‐carbamoylpyridine, namely, 2‐carbamoylpyridinium hydrogen chloranilate (systematic name: 2‐carbamoylpyridinium 2,5‐dichloro‐4‐hydroxy‐3,6‐dioxocyclohexa‐1,4‐dienolate), (I), 3‐carbamoylpyridinium hydrogen chloranilate, (II), and 4‐carbamoylpyridinium hydrogen chloranilate, (III), acid–base interactions involving H‐atom transfer are observed. The shortest interactions between the cation and the anion in (I) and (II) are pyridinium N—H...(O,O) bifurcated hydrogen bonds, which act as the primary intermolecular interaction in each crystal structure. In (III), an amide N—H...(O,O) bifurcated hydrogen bond, which is much weaker than the bifurcated hydrogen bonds in (I) and (II), connects the cation and the anion.     

Halogen,hydrogen and electrostatic interactions in 2‐amino‐5‐chloro‐1,3‐benzoxazol‐3‐ium nitrate and 2‐amino‐5‐chloro‐1,3‐benzoxazol‐3‐ium perchlorate

In the title compounds, C₇H₆ClN₂O⁺·NO₃⁻ and C₇H₆ClN₂O⁺·ClO₄⁻, the ions are connected by N—H...O hydrogen bonds and halogen interactions. Additionally, in the first compound, co‐operative π–π stacking and halogen...π interactions are observed. The energies of the observed interactions range from a value typical for very weak interactions (1.80 kJ mol⁻¹) to one typical for mildly strong interactions (53.01 kJ mol⁻¹). The iminium cations exist in an equilibrium form intermediate between exo‐ and endocyclic. This study provides structural insights relevant to the biochemical activity of 2‐amino‐5‐chloro‐1,3‐benzoxazole compounds.     

Products of the oxidation of 1‐(diaminomethylene)thiourea with hydrogen peroxide

Two oxidation products of 1‐(diaminomethylene)thiourea (HATU) are reported, obtained from reactions with hydrogen peroxide at two different concentrations; these are 3,5‐diamino‐1,2,4‐thiadiazole, C₂H₄N₄S, (I), related to HATU by intramolecular N—S bond formation, and 1‐(diaminomethylene)uronium hydrogen sulfate, C₂H₇N₄O⁺·HSO₄⁻, (II). In (I), molecular hydrogen‐bonded chains could be distinguished, further organized in a herring‐bone‐like pattern. The structure of (II) is stabilized by an extensive network of N—H...O and O—H...O hydrogen bonds, where hydrogen‐bonded anion chains and characteristic cation–anion motifs are present. The compounds are of importance not only with respect to crystal engineering, but also in the design of new synthetic routes to HATU transition metal complexes.     

Hydrogen‐bonded networks in 5‐chloropyridin‐2‐amine–fumaric acid (2/1) and 2‐aminopyridinium dl‐malate

Crystals of 5‐chloropyridin‐2‐amine–(2E)‐but‐2‐enedioate (2/1), 2C₅H₅ClN₂·C₄H₄O₄, (I), and 2‐aminopyridinium dl ‐3‐carboxy‐2‐hydroxypropanoate, C₅H₇N₂⁺·C₄H₅O₅⁻, (II), are built from the neutral 5‐chloropyridin‐2‐amine molecule and fumaric acid in the case of (I) and from ring‐N‐protonated 2‐aminopyridinium cations and malate anions in (II). The fumaric acid molecule lies on an inversion centre. In (I), the neutral 5‐chloropyridin‐2‐amine and fumaric acid molecules interact via hydrogen bonds, forming two‐dimensional layers parallel to the (100) plane, whereas in (II), oppositely charged units interact via ionic and hydrogen bonds, forming a three‐dimensional network.     

Efficient One‐Pot Syntheses of Betti Bases Catalyzed by 1‐Methyl‐3‐(2‐(sulfooxy)ethyl)‐1H‐imidazol‐3‐ium Chloride

The efficient one‐pot syntheses of Betti bases by the three‐component reaction of aromatic aldehyde, 2‐naphthalen, and acetonitrile (or benzamide) catalyzed by 1‐methyl‐3‐(2‐(sulfooxy)ethyl)‐1H‐imidazol‐3‐ium chloride is reported. The solvent can be recycled easily.     

Hydrogen‐bonding motifs in 4‐carboxy­phenyl­ammonium nitrate and perchlorate monohydrate,and in bis(4‐carboxy­phenyl­ammonium) sulfate

In the title compounds, C₇H₈NO₂⁺·NO₃⁻, (I), C₇H₈NO₂⁺·ClO₄⁻·H₂O, (II), and 2C₇H₈NO₂⁺·SO₄²⁻, (III), the carboxyl planes of the 4‐carboxy­phenyl­ammonium cations are twisted from the aromatic plane. A homonuclear C(8) hydrogen‐bonding motif of 4‐carboxy­phenyl­ammonium cations is observed in both (I) and (II), leading to `head‐to‐tail' layers. The cations in (III) form carboxyl group dimers, making a graph‐set motif of R₂²(8). In all the structures, anions connect the cationic layers and an infinite chain running along the c axis is observed, having the C₂²(6) graph‐set motif. Inter­estingly, in (II), the anions are connected through weak hydrogen bonds involving the water mol­ecules, leading to a graph‐set motif of R₄⁴(12). Alternate hydro­phobic and hydro­philic layers are observed in all three compounds as a result of the column‐like arrangement of the aromatic rings of the cations and the anions. Furthermore, in (I), head‐to‐tail N—H⋯O inter­actions and inter­actions linking the cations and anions form an R₆⁴(16) hydrogen‐bonding motif, resulting in a pseudo‐inversion centre at (, , 0).