(E)‐N′‐[5‐Chloro‐3‐methoxy‐2‐(4‐methylphenylsulfonyloxy)benzylidene]isonicotinohydrazide acetic acid solvate: hydrogen‐bonded network of alternating R44(42), R55(33) and R66(40) rings

In the title compound, C₂₁H₁₈ClN₃O₅S·C₂H₄O₂, a combination of O—H...O, N—H...O, C—H...O and C—H...N hydrogen bonds links the components into a complex network containing alternating R₄⁴(42), R₅⁵(33) and R₆⁶(40) rings.     

Hydrogen‐bonded sheets of R22(10) and R44(24) rings in 1‐deoxy‐1‐morpholino‐d‐fructopyranose

In the title compound, C₁₀H₁₉NO₆, both rings adopt almost perfect chair conformations and their mutual orientation is influenced by an intramolecular O—H...N hydrogen bond. The molecules are linked by three independent O—H...O hydrogen bonds into sheets containing equal numbers of R₂²(10) and R₄⁴(24) rings.     

2‐Cyano‐4‐iodoacetanilide: a hydrogen‐bonded chain of R22(12) and R22(14) rings

The molecules of 2‐cyano‐4‐iodoacetanilide, C₉H₇IN₂O, are linked by N—H...N and C—H...O hydrogen bonds into chains of alternating R₂²(12) and R₂²(14) rings.     

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.     

Diaquabis(4‐fluorobenzoato‐κO)bis(nicotinamide‐κN)cobalt(II)

The title compound, [Co(C₇H₄FO₂)₂(C₆H₆N₂O)₂(H₂O)₂], is a three‐dimensional hydrogen‐bonded supramolecular complex. The Co^II ion resides on a centre of symmetry and is in an octahedral coordination environment comprising two pyridyl N atoms, two carboxylate O atoms and two O atoms from water molecules. Intermolecular N—H...O and O—H...O hydrogen bonds produce R₃²(6), R₂²(12) and R₂²(16) rings, which lead to two‐dimensional chains. An extensive three‐dimensional network of C—H...F, N—H...O and O—H...O hydrogen bonds and π–π interactions are responsible for crystal stabilization.     

2‐Ethyl‐1‐[5‐(4‐methylphenyl)pyrazol‐3‐yl]‐3‐(thiophene‐2‐carbonyl)isothiourea: molecular ribbons containing three types of hydrogen‐bonded ring

The title compound, C₁₈H₁₈N₄OS₂, was prepared by reaction of S,S‐diethyl 2‐thenoylimidodithiocarbonate with 5‐amino‐3‐(4‐methylphenyl)‐1H‐pyrazole using microwave irradiation under solvent‐free conditions. In the molecule, the thiophene unit is disordered over two sets of atomic sites, with occupancies of 0.814 (4) and 0.186 (4), and the bonded distances provide evidence for polarization in the acylthiourea fragment and for aromatic type delocalization in the pyrazole ring. An intramolecular N—H...O hydrogen bond is present, forming an S(6) motif, and molecules are linked by N—H...O and N—H...N hydrogen bonds to form a ribbon in which centrosymmetric R₂²(4) rings, built from N—H...O hydrogen bonds and flanked by inversion‐related pairs of S(6) rings, alternate with centrosymmetric R₂²(6) rings built from N—H...N hydrogen bonds.     

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.     

5‐Methyl‐N‐[2‐nitro‐4‐(trifluoromethyl)phenyl]‐1H‐pyrazole‐3‐amine: a chain of hydrogen‐bonded R22(6) and R22(16) rings

The molecular skeleton of the title compound, C₁₁H₉F₃N₄O₂, is almost planar and exhibits a polarized (charge‐separated) electronic structure in the nitroaniline portion. Molecules are linked by N—H...N and C—H...O hydrogen bonds to form a chain in which centrosymmetric R₂²(6) and R₂²(16) rings alternate.     

N‐Benzyloxy‐1H‐benzotriazole‐1‐carboxamide: a hydrogen‐bonded tetramer based upon a rare R44(20) structural motif

The title compound, C₁₄H₁₂N₄O₂, is the first example of a heterocyclic substituted hydroxamic derivative. The asymmetric unit consists of two molecules. The molecules are linked into centrosymmetric R₄⁴(20) tetramers by four strong hydrogen bonds of the N—H...O and N—H...N types. These tetramers are connected through C—H...O interactions into a three‐dimensional network.     

trans‐Diaquabis(3‐hydroxybenzoato‐κO1)bis(nicotinamide‐κN1)copper(II)

The title compound, [Cu(C₇H₅O₃)₂(C₆H₆N₂O)₂(H₂O)₂], is a two‐dimensional hydrogen‐bonded supramolecular complex. The Cu^II ion resides on a centre of symmetry and is in an octahedral coordination environment comprising two pyridine N atoms, two carboxylate O atoms and two O atoms from water molecules. Intermolecular N—H...O and O—H...O hydrogen bonds produce R₂²(4), R₂²(8) and R₂²(15) rings which lead to one‐dimensional polymeric chains. An extensive two‐dimensional network of N—H...O and O—H...O hydrogen bonds and C—H...π interactions are responsible for crystal stabilization.     

An optically resolved crystal of thiomalate: (S)‐1‐phenylethanaminium (R)‐thiomalate

The asymmetric unit of the optically resolved title salt, C₈H₁₂N⁺·C₄H₅O₄S⁻, contains a 1‐phenylethanaminium monocation and a thiomalate (3‐carboxy‐2‐sulfanylpropanoate) monoanion. The absolute configurations of the cation and the anion are determined to be S and R, respectively. In the crystal, cation–anion N—H...O hydrogen bonds, together with anion–anion O—H...O and S—H...O hydrogen bonds, construct a two‐dimensional supramolecular sheet parallel to the ab plane. The two‐dimensional sheet is linked with the upper and lower sheets through C—H...π interactions to stack along the c axis.     

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.     

N—H⋯N and C—H⋯π inter­actions in 4‐amino‐3‐methyl‐5‐(p‐tol­yl)‐4H‐1,2,4‐triazole and 4‐amino‐3‐methyl‐5‐phenyl‐4H‐1,2,4‐triazole

The title compounds, C₁₀H₁₂N₄, (I), and C₉H₁₀N₄, (II), have been synthesized and characterized both spectroscopically and structurally. The dihedral angles between the triazole and benzene ring planes are 26.59 (9) and 42.34 (2)°, respectively. In (I), mol­ecules are linked principally by N—H⋯N hydrogen bonds involving the amino NH₂ group and a triazole N atom, forming R₄⁴(20) and R₂⁴(10) rings which link to give a three‐dimensional network of mol­ecules. The hydrogen bonding is supported by two different C—H⋯π inter­actions from the tolyl ring to either a triazole ring or a tolyl ring in neighboring mol­ecules. In (II), inter­molecular hydrogen bonds and C—H⋯π inter­actions produce R₃⁴(15) and R₄⁴(21) rings.     

The diastereoisomers 2‐[(S/R)‐2‐chloro‐3‐quinolyl]‐2‐[(R)‐1‐(4‐methoxyphenyl)ethylamino]acetonitrile at 100 K

In the structures of the two enantiopure diastereoisomers of the title compound, C₂₀H₁₈ClN₃O, which crystallize in different space groups, the molecules are very similar as far as bond distances and angles are concerned, but more substantial differences are observed in some torsion angles. The crystal structures of both molecules can be described as zigzag layers along the c axis. The packing is stabilized by hydrogen‐bond interactions of N—H...O, C—H...Cl and C—H...π types for 2‐[(R)‐2‐chloro‐3‐quinolyl]‐2‐[(R)‐1‐(4‐methoxyphenyl)ethylamino]acetonitrile, and of N—H...N, C—H...O and C—H...π types for 2‐[(S)‐2‐chloro‐3‐quinolyl]‐2‐[(R)‐1‐(4‐methoxyphenyl)ethylamino]acetonitrile, resulting in the formation of two‐ and three‐dimensional networks.     

trans‐Diaquabis(nicotinamide‐κN)bis(salicylato‐κO)cobalt(II)

The title compound, [Co(C₇H₅O₃)₂(C₆H₆N₂O)₂(H₂O)₂], forms a three‐dimensional hydrogen‐bonded supramolecular structure. The Co^II ion is in an octahedral coordination environment comprising two pyridyl N atoms, two carboxylate O atoms and two O atoms from water molecules. Intermolecular N—H...O and O—H...O hydrogen bonds produce R₂²(8), R₂²(12) and R₂²(14) rings, which lead to two‐dimensional chains. An extensive three‐dimensional supramolecular network of C—H...O, N—H...O and O—H...O hydrogen bonds and C—H...π interactions is responsible for crystal structure stabilization. This study is an example of the construction of a supramolecular assembly based on hydrogen bonds in mixed‐ligand metal complexes.     

3‐{[4‐Amino‐6‐methoxy‐2‐(methylsulfanyl)pyrimidin‐5‐yl]amino}‐1,2′‐biindenylidene‐1′,3′‐dione dimethyl sulfoxide solvate: π‐stacked sheets of hydrogen‐bonded chains of edge‐fused rings

In the title compound, C₂₄H₁₈N₄O₃S·C₂H₆OS, the biindenylidene component shows evidence of polarization of the electronic structure. The dimethyl sulfoxide solvent molecules are disordered over two sites, and they are linked to the biindenylidenedione components via N—H...O and C—H...O hydrogen bonds. A combination of N—H...N and N—H...O hydrogen bonds links the nonsolvent components into a chain of edge‐fused centrosymmetric R₂²(8) and R₂²(22) rings, and these chains are linked into sheets by a single aromatic π–π stacking interaction.     

1,3‐Ninhydrin dihydrazone featuring an R44(12) motif with symmetry and comprising only N and H atoms

In the title compound [systematic name: (1Z,3Z)‐1,3‐dihydrazinylidene‐1H‐inden‐2(3H)‐one], C₉H₈N₄O, isolated molecules possess approximate noncrystallographic C_2v symmetry and their cis conformation and planarity are assisted by a pair of short intramolecular N—H...O hydrogen bonds. Each molecule is asymmetrically involved in an extensive three‐dimensional network of N—H...O and N—H...N hydrogen bonds, and the structure also exhibits weaker π–π and C=O...C interactions. The structure features an R₄⁴(12) motif consisting solely of N and H atoms and possessing crystallographic symmetry.     

Two three‐dimensional networks in the binary molecular adducts 4‐methylimidazolium hydrogen terephthalate and bis(4‐methylimidazolium) terephthalate

Both the 1:1 and 2:1 molecular adducts of 4‐methylimidazole (4‐MeIm) and terephthalic acid (H₂TPA) are organic salts, viz. C₄H₇N₂⁺·C₈H₅O₄⁻, (I), and 2C₄H₇N₂⁺·C₈H₄O₄²⁻, (II), respectively. The component ions in (I) are linked by N—H...O and O—H...O hydrogen bonds into continuous two‐dimensional layers built from R₆⁴(32) hydrogen‐bond motifs running parallel to the (100) plane. These adjacent two‐dimensional layers are in turn linked by a combination of C—H...O, C—H...π and π–π interactions into a three‐dimensional network. In the crystal structure of (II), with the anion located on an inversion centre, only N—H...O hydrogen bonds result in two‐dimensional layers built from R₈⁸(42) hydrogen‐bond motifs running parallel to the (102) plane. Being similar to those in (I), these layers are also linked by means of C—H...O, C—H...π and π–π interactions, forming a three‐dimensional network. This study indicates that, on occasion, a change of the reactant concentration can exert a pivotal influence on the construction of supramolecular structures based on hydrogen bonds.     

Hydrogen bonding in the bromide salts of 4‐aminobenzoic acid and 4‐aminoacetophenone

In the title compounds, 4‐carboxyanilinium bromide, C₇H₈NO₂⁺·Br⁻, (I), and 4‐acetylanilinium bromide, C₈H₁₀NO⁺·Br⁻, (II), each asymmetric unit contains a discrete cation with a protonated amino group and a halide anion. Both crystal structures are characterized by two‐dimensional hydrogen‐bonded networks. The ions in (I) are connected via N—H...Br, N—H...O and O—H...Br hydrogen bonds, with three characteristic graph‐set motifs, viz. C(8), C₂¹(4) and R₃²(8). The centrosymmetric hydrogen‐bonded R²₂(8) dimer motif characteristic of carboxylic acids is absent. The ions in (II) are connected via N—H...Br and N—H...O hydrogen bonds, with two characteristic graph‐set motifs, viz. C(8) and R₄²(8). The significance of this study lies in its illustration of the differences between the supramolecular aggregations in two similar compounds. The presence of the methyl group in (II) at the site corresponding to the hydroxyl group in (I) results in a significantly different hydrogen‐bonding arrangement.     

4‐Iodo­anilinium 3‐nitro­phthalate(1–): tripartite sheets built from O—H...O and N—H...O hydrogen bonds

In the title compound, 4‐iodoanilinium 2‐carboxy‐6‐nitrobenzoate, C₆H₇IN⁺·C₈H₄NO₆⁻, the anions are linked by an O—H...O hydrogen bond [H...O = 1.78 Å, O...O = 2.614 (3) Å and O—H...O = 171°] into C(7) chains, and these chains are linked by two two‐centre N—H...O hydrogen bonds [H...O = 1.86 and 1.92 Å, N...O = 2.700 (3) and 2.786 (3) Å, and N—H...O = 153 and 158°] and one three‐centre N—H...(O)₂ hydrogen bond [H...O = 2.02 and 2.41 Å, N...O = 2.896 (3) and 2.789 (3) Å, N—H...O = 162 and 105°, and O...H...O = 92°], thus forming sheets con­taining R(6), R(8), R(13) and R(18) rings.