2‐[N‐(2,3‐Dimethylphenyl)carbamoyl]benzenesulfonamide and the 3,4‐ and 2,6‐dimethylphenyl analogues

The structures of 2‐[(2,3‐dimethylphenyl)carbamoyl]benzenesulfonamide, 2‐[(3,4‐dimethylphenyl)carbamoyl]benzenesulfonamide and 2‐[(2,6‐dimethylphenyl)carbamoyl]benzenesulfonamide, all C₁₅H₁₆N₂O₃S, are stabilized by extensive intra‐ and intermolecular hydrogen bonds. In all three structures, the sulfonamide and carbamoyl groups are involved in hydrogen bonding. In the 2,3‐dimethyl and 2,6‐dimethyl derivatives, dimeric units and chains of molecules are formed parallel to the c axis. In the 3,4‐dimethyl derivative, the hydrogen bonding creates tetrameric units, resulting in macrocyclic R₄⁴(22) rings that form sheets in the ab plane. The three analogues are closely related to the fenamate class of nonsteroidal anti‐inflammatory drugs.     

Hydrogen‐bond motifs in N‐monosubstituted derivatives of barbituric acid: 5‐allyl‐5‐isopropyl‐1‐methylbarbituric acid (enallylpropymal) and 1,5‐di(but‐2‐enyl)‐5‐ethylbarbituric acid

Both title structures exhibit essentially planar barbiturate rings. The crystal structure of enallylpropymal (5‐allyl‐5‐isopropyl‐1‐methylbarbituric acid), C₁₁H₁₆N₂O₃, is composed of centrosymmetric N—H...O hydrogen‐bonded dimers, while 1,5‐di(but‐2‐enyl)‐5‐ethylbarbituric acid, C₁₄H₂₀N₂O₃, forms N—H...O hydrogen‐bonded helical chains. Each of the ten known crystal structures of closely related N‐monosubstituted derivatives of barbituric acid displays one of the fundamental N—H...O hydrogen‐bonded motifs of the two title structures, i.e. either a dimer or a chain.     

Positional isomeric effect on the crystallization of chlorine‐substituted N‐phenyl‐2‐phthalimidoethanesulfonamide derivatives

The ortho‐, para‐ and meta‐chloro‐substituted N‐chlorophenyl‐2‐phthalimidoethanesulfonamide derivatives, C₁₆H₁₃ClN₂O₄S, have been structurally characterized by single‐crystal X‐ray crystallography. N‐(2‐Chlorophenyl)‐2‐phthalimidoethanesulfonamide, (I), has orthorhombic (P2₁2₁2₁) symmetry, N‐(4‐chlorophenyl)‐2‐phthalimidoethanesulfonamide, (II), has triclinic (P) symmetry and N‐(3‐chlorophenyl)‐2‐phthalimidoethanesulfonamide, (III), has monoclinic (P2₁/c) symmetry. The molecules of (I)–(III) are regioisomers which have crystallized in different space groups as a result of the differing intra‐ and intermolecular hydrogen‐bond interactions which are present in each structure. Compounds (I) and (II) are stabilized by N—H...O and C—H...O hydrogen bonds, while (III) is stabilized by N—H...O, C—H...O and C—H...Cl hydrogen‐bond interactions. The structure of (II) also displays π–π stacking interactions between the isoindole and benzene rings. All three structures are of interest with respect to their biological activities and have been studied as part of a programme to develop anticonvulsant drugs for the treatment of epilepsy.     

Amide hydrogen bonding: control of the molecular and extended structures of two symmetrical pyridine‐2‐carboxamide derivatives

The crystal structures of two symmetrical pyridine‐2‐carboxamides, namely N,N′‐(propane‐1,3‐diyl)bis(pyridine‐2‐carboxamide), C₁₅H₁₆N₄O₂, (I), and N,N′‐(butane‐1,4‐diyl)bis(pyridine‐2‐carboxamide), C₁₆H₁₈N₄O₂, (II), exhibit extended hydrogen‐bonded sequences involving their amide groups. In (I), conventional bifurcated amide–carbonyl (N—H)...O hydrogen bonding favours the formation of one‐dimensional chains, the axes of which run parallel to [001]. Unconventional bifurcated pyridine–carbonyl C—H...O hydrogen bonding links adjacent one‐dimensional chains to form a `porous' three‐dimensional lattice with interconnected, yet unfilled, voids of 60.6 (2) ų which combine into channels that run parallel to, and include, [001]. 4% of the unit‐cell volume of (I) is vacant. Compound (II) adopts a Z‐shaped conformation with inversion symmetry, and exhibits an extended structure comprising one‐dimensional hydrogen‐bonded chains along [100] in which individual molecules are linked by complementary pairs of amide N—H...O hydrogen bonds. These hydrogen‐bonded chains interlock viaπ–π interactions between pyridine rings of neighbouring molecules to form sheets parallel with (010); each sheet is one Z‐shaped molecule thick and separated from the next sheet by the b‐axis dimension [7.2734 (4) Å].     

(2S)‐1‐Carbamoylpyrrolidine‐2‐carboxylic acid

In the title compound, also known as N‐carbamoyl‐l ‐proline, C₆H₁₀N₂O₃, the pyrrolidine ring adopts a half‐chair conformation, whereas the carboxyl group and the mean plane of the ureide group form an angle of 80.1 (2)°. Molecules are joined by N—H...O and O—H...O hydrogen bonds into cyclic structures with graph‐set R²₂(8), forming chains in the b‐axis direction that are further connected via N—H...O hydrogen bonds into a three‐dimensional network.     

Polymorph VI of sulfapyridine: interpenetrating two‐ and three‐dimensional hydrogen‐bonded nets formed from two tautomeric forms

Polymorph VI of 4‐amino‐N‐(2‐pyridyl)benzenesulfonamide, C₁₁H₁₁N₃O₂S, is monoclinic (space group P2₁/n). The asymmetric unit contains two different tautomeric forms. The structure displays N—H...N and N—H...O hydrogen bonding. The two independent molecules form two separate two‐ and three‐dimensional hydrogen‐bonded networks which interpenetrate. The observed patterns of hydrogen bonding are analogous to those in polymorph I of sulfathiazole.     

Bilayers in 4‐iodo‐N‐(2‐iodo‐4‐nitrophenyl)benzamide generated by a combination of an N—H⋯O=C hydrogen bond and two independent iodo–nitro interactions

Molecules of the title compound, C₁₃H₈I₂N₂O₃, are linked into C(4) chains by a single N—H⋯O=C hydrogen bond [H⋯O = 2.10 Å, N⋯O = 2.832 (5) Å and N—H⋯O = 140°]. Two independent two‐centre iodo–nitro interactions, both involving the same O atom but different I atoms [I⋯O = 3.205 (3) and 3.400 (3) Å, and C—I⋯O = 160.4 (2) and 155.7 (2)°], link the hydrogen‐bonded chains into bilayers.     

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.     

Two new polymorphs of 2,6‐diaminopyrimidin‐4(3H)‐one monohydrate

The title compound, C₄H₆N₄O·H₂O, crystallized simultaneously as a triclinic and a monoclinic polymorph from an aqueous solution of 2,4‐diaminopyrimidin‐6‐ol. Previously, an orthorhombic polymorph was isolated under the same experimental conditions. The molecular geometric parameters in the two present polymorphs and the previously reported orthorhombic polymorph are similar, but the structures differ in the details of their crystal packing. In the triclinic system, the diaminopyrimidinone molecules are connected to one another via N—H...O and N—H...N hydrogen bonding to form infinite chains in the [011] direction. The chains are further hydrogen bonded to the water molecules, resulting in a three‐dimensional network. In the monoclinic system, the diaminopyrimidinone molecules are hydrogen bonded together into two‐dimensional networks parallel to the bc plane. The water molecules link the planes to form a three‐dimensional polymeric structure.     

Two isomorphous ZnII/CoII complexes with tri‐tert‐butoxysilanethiol and histamine,and (4‐hydroxymethyl‐1H‐imidazole‐κN)bis(tri‐tert‐butoxysilanethiolato‐κ2O,S)zinc(II)

The complexes [2‐(1H‐imidazol‐4‐yl‐κN³)ethylamine‐κN]bis(tri‐tert‐butoxysilanethiolato‐κS)cobalt(II), [Co(C₁₂H₂₇O₃SSi)₂(C₅H₉N₃)], and [2‐(1H‐imidazol‐4‐yl‐κN³)ethylamine‐κN]bis(tri‐tert‐butoxysilanethiolato‐κS)zinc(II), [Zn(C₁₂H₂₇O₃SSi)₂(C₅H₉N₃)], are isomorphous. The central Zn^II/Co^II ions are surrounded by two S atoms from the tri‐tert‐butoxysilanethiolate ligand and by two N atoms from the chelating histamine ligand in a distorted tetrahedral geometry, with two intramolecular N—H...O hydrogen‐bonding interactions between the histamine NH₂ groups and tert‐butoxy O atoms. Molecules of the complexes are joined into dimers via two intermolecular bifurcated N—H...(S,O) hydrogen bonds. The Zn^II atom in [(1H‐imidazol‐4‐yl‐κN³)methanol]bis(tri‐tert‐butoxysilanethiolato‐κ²O,S)zinc(II), [Zn(C₁₂H₂₇O₃SSi)₂(C₄H₆N₂O)], is five‐coordinated by two O and two S atoms from the O,S‐chelating silanethiolate ligand and by one N atom from (1H‐imidazol‐4‐yl)methanol; the hydroxy group forms an intramolecular hydrogen bond with sulfur. Molecules of this complex pack as zigzag chains linked by N—H...O hydrogen bonds. These structures provide reference details for cysteine‐ and histidine‐ligated metal centers in proteins.     

1:1 Adduct of (S,S)‐4‐amino‐3,5‐bis­(1‐hydroxy­ethyl)‐1,2,4‐triazole with (S,S)‐1,2‐bis­(2‐hydroxy­propionyl)­hydrazine stabilized by eight hydrogen bonds

The structure of the cocrystallized 1:1 adduct of (S,S)‐4‐amino‐3,5‐bis­(1‐hydroxy­ethyl)‐1,2,4‐triazole and (S,S)‐1,2‐bis­(2‐hydroxy­propionyl)­hydrazine, C₆H₁₂N₄O₂·C₆H₁₂N₂O₄, has tetra­gonal symmetry. All eight O‐ and N‐bound H atoms are involved in inter­molecular hydrogen bonds, resulting in infinite zigzag chains of the triazole mol­ecules, with the hydrazine mol­ecules filling the gaps between the chains and completing a three‐dimensional hydrogen‐bonded array.     

Conversion of 3‐amino‐4‐arylamino‐1H‐isochromen‐1‐ones to 1‐arylisochromeno[3,4‐d][1,2,3]triazol‐5(1H)‐ones: synthesis,spectroscopic characterization and the structures of four products and one ring‐opened derivative

An efficient synthesis of 1‐arylisochromeno[3,4‐d][1,2,3]triazol‐5(1H)‐ones, involving the diazotization of 3‐amino‐4‐arylamino‐1H‐isochromen‐1‐ones in weakly acidic solution, has been developed and the spectroscopic characterization and crystal structures of four examples are reported. The molecules of 1‐phenylisochromeno[3,4‐d][1,2,3]triazol‐5(1H)‐one, C₁₅H₉N₃O₂, (I), are linked into sheets by a combination of C—H…N and C—H…O hydrogen bonds, while the structures of 1‐(2‐methylphenyl)isochromeno[3,4‐d][1,2,3]triazol‐5(1H)‐one, C₁₆H₁₁N₃O₂, (II), and 1‐(3‐chlorophenyl)isochromeno[3,4‐d][1,2,3]triazol‐5(1H)‐one, C₁₅H₈ClN₃O₂, (III), each contain just one hydrogen bond which links the molecules into simple chains, which are further linked into sheets by π‐stacking interactions in (II) but not in (III). In the structure of 1‐(4‐chlorophenyl)isochromeno[3,4‐d][1,2,3]triazol‐5(1H)‐one, (IV), isomeric with (III), a combination of C—H…O and C—H…π(arene) hydrogen bonds links the molecules into sheets. When compound (II) was exposed to a strong acid in methanol, quantitative conversion occurred to give the ring‐opened transesterification product methyl 2‐[4‐hydroxy‐1‐(2‐methylphenyl)‐1H‐1,2,3‐triazol‐5‐yl]benzoate, C₁₇H₁₅N₃O₃, (V), where the molecules are linked by paired O—H…O hydrogen bonds to form centrosymmetric dimers.     

N‐(X‐Chlorophenyl)‐4‐hydroxy‐2‐methyl‐2H‐1,2‐benzothiazine‐3‐carboxamide 1,1‐dioxide (with X = 2 and 4)

The structures of N‐(2‐chlorophenyl)‐4‐hydroxy‐2‐methyl‐2H‐1,2‐benzothiazine‐3‐carboxamide 1,1‐dioxide and N‐(4‐chlorophenyl)‐4‐hydroxy‐2‐methyl‐2H‐1,2‐benzothiazine‐3‐carboxamide 1,1‐dioxide, both C₁₆H₁₃ClN₂O₄S, are stabilized by extensive intramolecular hydrogen bonds. The 4‐chloro derivative forms dimeric pairs of molecules lying about inversion centres as a result of intermolecular N—H...O hydrogen bonds, forming 14‐membered rings representing an R₂²(14) motif; the 2‐chloro derivative is devoid of any such intermolecular hydrogen bonds. The heterocyclic thiazine rings in both structures adopt half‐chair conformations.     

A three‐dimensional supramolecular network built with the zigzag chain complex bis(5‐carboxy‐1H‐imidazole‐4‐carboxyl­ato)copper(II)

In the title complex, poly[copper(II)‐di‐μ‐5‐carboxy‐1H‐imidazole‐4‐carboxyl­ato], [Cu(C₅H₃N₂O₄)₂]_n or [Cu(H₂Imda)₂]_n, each imidazole moiety is bonded to the Cu atom via O and N atoms to give a square‐planar coordination [Cu—O = 2.014 (2) and 2.016 (2) Å, and Cu—N = 1.982 (3) and 1.992 (2) Å]. The distorted square‐pyramidal geometry at the Cu atom results from coordination to an adjacent O atom [Cu—O = 2.305 (2) Å], which generates zigzag chains. There is a sixth, weaker, octahedral coordination to the Cu atom from an inversion‐related O atom [Cu—O = 3.090 (2) Å], which links the chains into sheets in the (100) plane. Imidazole moieties in the sheets are linked in the [100] direction by pairs of N—H⋯O and C—H⋯O hydrogen bonds, thus generating a three‐dimensional network.     

Three new [XC(O)NH]P(O)[N(CH2C6H5)2]2 phosphoric triamides (X = CClF2, 3‐F‐C6H4 and 3,5‐F2‐C6H3): a database analysis of tertiary N‐atom geometry in compounds with a C(O)NHP(O)[N]2 core

In the phosphoric triamides N,N,N′,N′‐tetrabenzyl‐N′′‐(2‐chloro‐2,2‐difluoroacetyl)phosphoric triamide, C₃₀H₂₉ClF₂N₃O₂P, (I), N,N,N′,N′‐tetrabenzyl‐N′′‐(3‐fluorobenzoyl)phosphoric triamide, C₃₅H₃₃FN₃O₂P, (II), and N,N,N′,N′‐tetrabenzyl‐N′′‐(3,5‐difluorobenzoyl)phosphoric triamide, C₃₅H₃₂F₂N₃O₂P, (III), the tertiary N atoms of the dibenzylamido groups have sp² character with minimal deviation from planarity. The sums of the three bond angles about the N atoms in (I)–(III) deviate by less than 8° from the planar value of 360°. The geometries of the tertiary N atoms in all phosphoric triamides with C(O)NHP(O)[N]₂ skeletons deposited in the Cambridge Structural Database [CSD; Allen (2002). Acta Cryst. B 58 , 380–388] have been examined and the bond‐angle sums at the two tertiary N atoms (SUM1 and SUM2) and the parameter ΔSUM (= SUM1 − SUM2) considered. It was found that in compounds with a considerable ΔSUM value, the more pyramidal N atoms are usually oriented so that the corresponding lone electron pair is anti with respect to the P=O group. In (I), (II) and (III), the phosphoryl and carbonyl groups, separated by an N atom, are anti with respect to each other. In the C(O)NHP(O) fragment of (I)–(III), the P—N bond is longer and the O—P—N angle is contracted compared with the other two P—N bonds and the O—P—N angles in the molecules. These effects are also seen in analogous compounds deposited in the CSD. Compounds with [C(O)NH]P(O)[N]X (X≠ N), such as compounds with a [C(O)NH]P(O)[N][O] skeleton, have not been considered here. Also, compounds with a [C(O)NH]₂P(O)[N] fragment have not been reported to date. In the crystal structures of all three title compounds, adjacent molecules are linked via pairs of P=O...H—N hydrogen bonds, forming dimers with C_i symmetry.     

Conformational isomers of the [(5‐methyl‐2‐pyridinio)aminomethylene]diphosphonate dianion and [(5‐methyl‐2‐pyridyl)aminomethylene]diphosphonate trianion in salts with 4‐aminopyridine and ammonia

The crystal structures of two salts, products of the reactions between [(5‐methyl‐2‐pyridyl)aminomethylene]bis(phosphonic acid) and 4‐aminopyridine or ammonia, namely bis(4‐aminopyridinium) hydrogen [(5‐methyl‐2‐pyridinio)aminomethylene]diphosphonate 2.4‐hydrate, 2C₅H₇N₂⁺·C₇H₁₀N₂O₆P₂²⁻·2.4H₂O, (I), and triammonium hydrogen [(5‐methyl‐2‐pyridyl)aminomethylene]diphosphonate monohydrate, 3NH₄⁺·C₇H₉N₂O₆P₂³⁻·H₂O, (II), have been determined. In (I), the Z configuration of the ring N—C and amino N—H bonds of the bisphosphonate dianion with respect to the C_ring—N_amino bond is consistent with that of the parent zwitterion. Removing the H atom from the pyridyl N atom results in the opposite E configuration of the bisphosphonate trianion in (II). Compound (I) exhibits a three‐dimensional hydrogen‐bonded network, in which 4‐aminopyridinium cations and water molecules are joined to ribbons composed of anionic dimers linked by O—H...O and N—H...O hydrogen bonds. The supramolecular motif resulting from a combination of these three interactions is a common phenomenon in crystals of all of the Z‐isomeric zwitterions of 4‐ and 5‐substituted (2‐pyridylaminomethylene)bis(phosphonic acid)s studied to date. In (II), ammonium cations and water molecules are linked to chains of trianions, resulting in the formation of double layers.     

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.     

Two Fe3(μ3‐S)2(CO)8 clusters with terminal N‐heterocyclic carbenes

The title compounds with terminal N‐heterocyclic carbenes, namely octacarbonyl(imidazolidinylidene‐κC²)di‐μ₃‐sulfido‐triiron(II)(2 Fe—Fe), [Fe₃(C₃H₆N₂)(μ₃‐S)₂(CO)₈], (I), and octacarbonyl(1‐methylimidazo[1,5‐a]pyridin‐3‐ylidene‐κC³)di‐μ₃‐sulfido‐triiron(II)(2 Fe—Fe), [Fe₃(C₈H₈N₂)(μ₃‐S)₂(CO)₈], (II), have been synthesized. Each compound contains two Fe—Fe bonds and two S atoms above and below a triiron triangle. One of the eight carbonyl ligands deviates significantly from linearity. In (I), dimers generated by an N—H...S hydrogen bond are linked into [001] double chains by a second N—H...S hydrogen bond. These chains are packed by a C—H...O hydrogen bond to yield [101] sheets. In (II), dimers generated by an N—H...S hydrogen bond are linked by C—H...O hydrogen bonds to form [111] double chains.     

Ethyl N‐[2‐(hydroxy­acetyl)­phenyl]­carbamate,ethyl N‐[2‐(hydroxy­acetyl)‐4‐iodo­phenyl]­carbamate and ethyl N‐[2‐(hydroxy­acetyl)‐4‐methyl­phenyl]­carbamate

In ethyl N‐[2‐(hydroxy­acetyl)phenyl]carbamate, C₁₁H₁₃NO₄, all of the non‐H atoms lie on a mirror plane in the space group Pnma; the mol­ecules are linked into simple chains by a single C—H⋯O hydrogen bond. The mol­ecules of ethyl N‐[2‐(hydroxy­acetyl)‐4‐iodo­phenyl]carbamate, C₁₁H₁₂INO₄, are linked into sheets by a combination of O—H⋯I and C—H⋯O hydrogen bonds and a dipolar I⋯O contact. Ethyl N‐­[2‐(hydroxy­acetyl)‐4‐methyl­phenyl]carbamate, C₁₂H₁₅NO₄, crystallizes with Z′ = 2 in the space group P; pairs of mol­ecules are weakly linked by an O—H⋯O hydrogen bond and these aggregates are linked into chains by two independent aromatic π–π stacking inter­actions.