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‐Vinyl­benzyl analogs of adenine and uracil: reactive monomers for nucleobase polymeric resins

The crystal structures of 9‐(4‐vinyl­benzyl)­adenine, C₁₄H₁₃N₅, and 1‐(4‐vinyl­benzyl)­uracil, C₁₃H₁₂N₂O₂, are composed of zigzag ribbon‐like structures that are stabilized by conventional (N—H?N‐type) hydrogen bonds for the former and conventional (N—H?O‐type) and non‐conventional (C—H?O‐type) hydrogen bonds for the latter; the hydrogen‐bonding patterns are represented by graph‐sets R(9) and R(8), respectively. The adenine and uracil moieties in these alkyl­ated derivatives are planar and are inclined at angles of 84.44 (4) and 79.07 (7)°, respectively, with respect to the phenyl rings.     

Cocrystals of 6‐propyl‐2‐thiouracil: N—H...O versus N—H...S hydrogen bonds

In order to investigate the relative stability of N—H...O and N—H...S hydrogen bonds, we cocrystallized the antithyroid drug 6‐propyl‐2‐thiouracil with two complementary heterocycles. In the cocrystal pyrimidin‐2‐amine–6‐propyl‐2‐thiouracil (1/2), C₄H₅N₃·2C₇H₁₀N₂OS, (I), the `base pair' is connected by one N—H...S and one N—H...N hydrogen bond. Homodimers of 6‐propyl‐2‐thiouracil linked by two N—H...S hydrogen bonds are observed in the cocrystal N‐(6‐acetamidopyridin‐2‐yl)acetamide–6‐propyl‐2‐thiouracil (1/2), C₉H₁₁N₃O₂·2C₇H₁₀N₂OS, (II). The crystal structure of 6‐propyl‐2‐thiouracil itself, C₇H₁₀N₂OS, (III), is stabilized by pairwise N—H...O and N—H...S hydrogen bonds. In all three structures, N—H...S hydrogen bonds occur only within R₂²(8) patterns, whereas N—H...O hydrogen bonds tend to connect the homo‐ and heterodimers into extended networks. In agreement with related structures, the hydrogen‐bonding capability of C=O and C=S groups seems to be comparable.     

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.     

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.     

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.     

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.     

N6‐Furfuryladenine (kinetin) hydrochloride

In the title compound, N⁶‐furfuryl­adenin‐3‐ium chloride, C₁₀H₁₀N₅O⁺·Cl⁻, the adenine moiety exists as the N3‐protonated N7–H tautomer. The orientation of the N6 substituent (furfuryl moiety) is distal to the imidazole ring of the adenine base. The dihedral angle between the adenine plane and the furfuryl ring plane is 76.1 (2)°. Three N—H⋯Cl hydrogen bonds are responsible for the formation of a supramolecular chain‐like pattern. These supramolecular chains are interconnected by C—H⋯Cl hydrogen bonds to form a hydrogen‐bonded sheet and a three‐dimensional hydrogen‐bonded network.     

Tetraaquabis[5‐(3‐pyridyl‐κN)pyrimidine]zinc(II) bis(trifluoromethanesulfonate): a novel cationic complex and three‐dimensional hydrogen‐bonded network

The title compound, [Zn(C₉H₇N₃)₂(H₂O)₄](CF₃O₃S)₂, contains an octahedral [ZnL₂(H₂O)₄]²⁺ cationic complex with trans geometry (Zn site symmetry ), and each 5‐(3‐pyridyl)pyrimidine (L) ligand is coordinated in a monodentate fashion through the pyridine N atom. In the extended structure, these complexes, with both hydrogen‐bond acceptor (pyrimidine) and donor (H₂O) functions, are linked to each other by intermolecular water–pyrimidine O—H...N hydrogen‐bonding interactions, resulting in a double chain along the crystallographic a axis. The trifluoromethanesulfonate anions are integrated into the chains via O—H...O hydrogen bonds between the coordinated water and sulfonate O atoms. These double chains are associated into a novel three‐dimensional network through interchain water–pyrimidine O—H...N hydrogen bonds. The asymmetric ligand plays an important role in constructing this unusual supramolecular structure.     

Three‐dimensional hydrogen‐bonded framework structures in flunarizinium nicotinate and flunarizinediium bis(4‐toluenesulfonate) dihydrate

The structures of two salts of flunarizine, namely 1‐bis[(4‐fluorophenyl)methyl]‐4‐[(2E)‐3‐phenylprop‐2‐en‐1‐yl]piperazine, C₂₆H₂₆F₂N₂, are reported. In flunarizinium nicotinate {systematic name: 4‐bis[(4‐fluorophenyl)methyl]‐1‐[(2E)‐3‐phenylprop‐2‐en‐1‐yl]piperazin‐1‐ium pyridine‐3‐carboxylate}, C₂₆H₂₇F₂N₂⁺·C₆H₄NO₂⁻, (I), the two ionic components are linked by a short charge‐assisted N—H...O hydrogen bond. The ion pairs are linked into a three‐dimensional framework structure by three independent C—H...O hydrogen bonds, augmented by C—H...π(arene) hydrogen bonds and an aromatic π–π stacking interaction. In flunarizinediium bis(4‐toluenesulfonate) dihydrate {systematic name: 1‐[bis(4‐fluorophenyl)methyl]‐4‐[(2E)‐3‐phenylprop‐2‐en‐1‐yl]piperazine‐1,4‐diium bis(4‐methylbenzenesulfonate) dihydrate}, C₂₆H₂₈F₂N₂²⁺·2C₇H₇O₃S⁻·2H₂O, (II), one of the anions is disordered over two sites with occupancies of 0.832 (6) and 0.168 (6). The five independent components are linked into ribbons by two independent N—H...O hydrogen bonds and four independent O—H...O hydrogen bonds, and these ribbons are linked to form a three‐dimensional framework by two independent C—H...O hydrogen bonds, but C—H...π(arene) hydrogen bonds and aromatic π–π stacking interactions are absent from the structure of (II). Comparisons are made with some related structures.     

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.     

N‐{4‐Bromo‐2‐[(3‐bromo‐1‐phenylsulfonyl‐1H‐indol‐2‐yl)methyl]‐5‐methoxyphenyl}acetamide

In the title compound, C₂₄H₂₀Br₂N₂O₄S, the indole ring system is planar and the S atom has a distorted tetrahedral configuration. The sulfonyl‐bound phenyl ring is orthogonal to the indole ring system and the conformation of the phenyl­sulfonyl substituent with respect to the indole moiety is influenced by intramolecular C—H⃛O hydrogen bonds involving the two sulfonyl O atoms. The mean plane through the acetyl­amido group makes a dihedral angle of 57.0 (1)° with the phenyl ring of the benzyl moiety. In the crystal, glide‐related mol­ecules are linked together by N—H⃛O hydrogen bonds and C—H⃛π interactions to form molecular chains, which extend through the crystal. Inversion‐related chains are interlinked by C—H⃛π interactions to form molecular layers parallel to the bc plane. These layers are interconnected through π–π interactions involving the five‐ and six‐membered rings of the indole moiety.     

catena‐Poly[[[1‐benzoyl‐2‐(2‐hydroxyethyl)‐3‐(2‐pyridyl)guanidine]chloridocopper(II)] chloride 0.61‐hydrate]

The title copper(II) complex, {[CuCl(C₁₅H₁₆N₄O₂)]Cl·0.61H₂O}_n, is a one‐dimensional zigzag coordination polymer structure extending along the (010) direction. The Cu^II atom has a square‐pyramidal geometry, where the basal plane is formed by two cis N atoms and one O atom from the ligand, and by a Cl atom. The apical position is occupied by a carbonyl O atom from a symmetry‐related molecule. In the crystal structure, there are O—H...Cl and N—H...Cl hydrogen bonds, which link parallel polymer chains along the c direction, so building a two‐dimensional structure via the interstitial Cl atoms.     

Hydrogen‐bonded bilayers in ­piperazinium(2+) bis(mandelate) bis(methanol) solvate

In the title compound, C₄H₁₂N₂²⁺·2C₈H₇O₃^?·2CH₄O, the cations lie across centres of inversion and are disordered over two orientations with equal occupancy; there are equal numbers of (R)‐ and (S)‐mandelate anions present (mandelate is α‐hydroxy­benzene­acetate). The anions and the neutral water mol­ecules are linked by O—H?O hydrogen bonds [O?O 2.658 (3) and 2.682 (3) Å, and O—H?O 176 and 166°] into deeply folded zigzag chains. Each orientation of the cation forms two symmetry‐related two‐centre N—H?O hydrogen bonds [N?O 2.588 (4) and 2.678 (4) Å, and N—H?O 177 and 171°] and two asymmetric, but planar, three‐centre N—H?(O)₂ hydrogen bonds [N?O 2.686 (4)–3.137 (4) Å and N—H?O 137–147°], and by means of these the cations link the anion/water chains into bilayers.     

A structural study of 4‐aminoantipyrine and six of its Schiff base derivatives

Six derivatives of 4‐amino‐1,5‐dimethyl‐2‐phenyl‐2,3‐dihydro‐1H‐pyrazol‐3‐one (4‐aminoantipyrine), C₁₁H₁₃N₃O, (I), have been synthesized and structurally characterized to investigate the changes in the observed hydrogen‐bonding motifs compared to the original 4‐aminoantipyrine. The derivatives were synthesized from the reactions of 4‐aminoantipyrine with various aldehyde‐, ketone‐ and ester‐containing molecules, producing (Z)‐methyl 3‐[(1,5‐dimethyl‐3‐oxo‐2‐phenyl‐2,3‐dihydro‐1H‐pyrazol‐4‐yl)amino]but‐2‐enoate, C₁₆H₁₉N₃O₃, (II), (Z)‐ethyl 3‐[(1,5‐dimethyl‐3‐oxo‐2‐phenyl‐2,3‐dihydro‐1H‐pyrazol‐4‐yl)amino]but‐2‐enoate, C₁₇H₂₁N₃O₃, (III), ethyl 2‐[(1,5‐dimethyl‐3‐oxo‐2‐phenyl‐2,3‐dihydro‐1H‐pyrazol‐4‐yl)amino]cyclohex‐1‐enecarboxylate, C₂₀H₂₅N₃O₃, (IV), (Z)‐ethyl 3‐[(1,5‐dimethyl‐3‐oxo‐2‐phenyl‐2,3‐dihydro‐1H‐pyrazol‐4‐yl)amino]‐3‐phenylacrylate, C₂₂H₂₃N₃O₃, (V), 2‐cyano‐N‐(1,5‐dimethyl‐3‐oxo‐2‐phenyl‐2,3‐dihydro‐1H‐pyrazol‐4‐yl)acetamide, C₁₄H₁₄N₄O₂, (VI), and (E)‐methyl 4‐{[(1,5‐dimethyl‐3‐oxo‐2‐phenyl‐2,3‐dihydro‐1H‐pyrazol‐4‐yl)amino]methyl}benzoate, C₂₀H₁₉N₃O₃, (VII). The asymmetric units of all these compounds have one molecule on a general position. The hydrogen bonding in (I) forms chains of molecules via intermolecular N—H...O hydrogen bonds around a crystallographic sixfold screw axis. In contrast, the formation of enamines for all derived compounds except (VII) favours the formation of a six‐membered intramolecular N—H...O hydrogen‐bonded ring in (II)–(V) and an intermolecular N—H...O hydrogen bond in (VI), whereas there is an intramolecular C—H...O hydrogen bond in the structure of imine (VII). All the reported compounds, except for (II), feature π–π interactions, while C—H...π interactions are observed in (II), C—H...O interactions are observed in (I), (III), (V) and (VI), and a C—O...π interaction is observed in (II).     

Infinite ladder‐like chains organized into a three‐dimensional zigzag supramolecular architecture in 9‐deazahypoxanthine

The asymmetric unit of the title compound, C₆H₅N₃O, consists of discrete molecules of 9‐deazahypoxanthine [systematic name: 3H‐pyrrolo[3,2‐d]pyrimidin‐4(5H)‐one]. The structure displays N—H...O hydrogen bonding, connecting the molecules into centrosymmetric dimers. These dimers are then connected by N—H...N hydrogen bonds into a ladder‐like chain along the c axis. The secondary structure is stabilized by weak noncovalent contacts of the C—H...O and C—H...C types, as well as by π–π stacking interactions, which organize the structure into a zigzag architecture.     

Triaqua(μ‐7‐iodo‐8‐oxidoquinoline‐5‐sulfonato‐κ2N,O8)dioxidouranium(VI) dihydrate

In the title compound, [U(C₉H₄INO₄S)O₂(H₂O)₃]·2H₂O, the asymmetric unit contains a UO₂²⁺ ion coordinated by the N and O atoms of a 7‐iodo‐8‐oxidoquinoline‐5‐sulfonate dianion (ferron anion) and three coordinated water molecules, and two uncoordinated water molecules. The UO₂²⁺ ion exhibits a seven‐coordinate pentagonal bipyramidal geometry. The usual sulfonate oxygen coordination is absent but the sulfonate O atoms, along with the coordinated and lattice water molecules, play a vital role in assembling the three‐dimensional structure via an extensive network of intermolecular O—H...O hydrogen bonds and π–π stacking interactions.     

A three‐dimensional framework in 2,2′‐biimidazolium bis(2,2′‐biimidazole‐κ2N,N′)bis(biphenyl‐2,4′‐dicarboxylato‐κO)manganese(II) hexahydrate

In the title salt, (C₆H₈N₄)[Mn(C₁₄H₈O₄)₂(C₆H₆N₄)₂]·6H₂O, the Mn^II atom lies on an inversion centre and is coordinated by four N atoms from two 2,2′‐biimidazole (biim) ligands and two O atoms from two biphenyl‐2,4′‐dicarboxylate (bpdc) anions to give a slightly distorted octahedral coordination, while the cation lies about another inversion centre. Adjacent [Mn(bpdc)₂(biim)₂]²⁻ anions are linked via two pairs of N—H...O hydrogen bonds, leading to an infinite chain along the [100] direction. The protonated [H₂biim]²⁺ moiety acts as a charge‐compensating cation and space‐filling structural subunit. It bridges two [Mn(bpdc)₂(biim)₂]²⁻ anions through two pairs of N—H...O hydrogen bonds, constructing two R₂²(9) rings, leading to a zigzag chain in the [2] direction, which gives rise to a ruffled set of [H₂biim]²⁺[Mn(bpdc)₂(biim)₂]²⁻ moieties in the [01] plane. The water molecules give rise to a chain structure in which O—H...O hydrogen bonds generate a chain of alternating four‐ and six‐membered water–oxygen R₄²(8) and R₆⁶(12) rings, each lying about independent inversion centres giving rise to a chain along the [100] direction. Within the water chain, the (H₂O)₆ water rings are hydrogen bonded to two O atoms from two [Mn(bpdc)₂(biim)₂]²⁻ anions, giving rise to a three‐dimensional framework.     

Supramolecular aggregation in three 4‐aryl‐6‐(1H‐indol‐3‐yl)‐3‐methyl‐1‐phenyl‐1H‐pyrazolo[3,4‐b]pyridine‐5‐carbonitriles

Both 6‐(1H‐indol‐3‐yl)‐3‐methyl‐4‐(4‐methylphenyl)‐1‐phenyl‐1H‐pyrazolo[3,4‐b]pyridine‐5‐carbonitrile and 6‐(1H‐indol‐3‐yl)‐3‐methyl‐4‐(4‐methoxyphenyl)‐1‐phenyl‐1H‐pyrazolo[3,4‐b]pyridine‐5‐carbonitrile crystallize from dimethylformamide solutions as stoichiometric 1:1 solvates, viz. C₂₉H₂₁N₅·C₃H₇NO, (I), and C₂₉H₂₁N₅O·C₃H₇NO, (II), respectively; however, 6‐(1H‐indol‐3‐yl)‐3‐methyl‐1‐phenyl‐4‐(3,4,5‐trimethoxyphenyl)‐1H‐pyrazolo[3,4‐b]pyridine‐5‐carbonitrile, C₃₁H₂₅N₅O₃, (III), crystallizes in the unsolvated form. The heterocyclic components of (I) are linked by C—H...π(arene) hydrogen bonds to form cyclic centrosymmetric dimers, from which the solvent molecules are pendent, linked by N—H...O hydrogen bonds. In (II), the heterocyclic components are linked by a combination of C—H...N and C—H...π(arene) hydrogen bonds into chains containing two types of centrosymmetric ring, and the pendent solvent molecules are linked to these chains by N—H...O hydrogen bonds. Molecules of (III) are linked into simple C(12) chains by an N—H...O hydrogen bond, and these chains are weakly linked into pairs by an aromatic π–π stacking interaction.     

Multiple hydrogen bonds in cytosinium zoledronate trihydrate

The asymmetric unit of the title compound [systematic name: 4‐amino‐2‐oxo‐2,3‐dihydropyrimidin‐1‐ium 1‐hydroxy‐2‐(1H,3H‐imidazol‐3‐ium‐1‐yl)ethylidenediphosphonate trihydrate], C₄H₆N₃O⁺·C₅H₉N₂O₇P₂⁻·3H₂O, contains one cytosinium cation, one zoledronate anion and three water molecules. The zoledronate anion has a zwitterionic character, in which each phosphonate group is singly deprotonated and an imidazole N atom is protonated. Furthermore, proton transfer takes place from one of the phosphonic acid groups of the zoledronate anion to one of the N atoms of the cytosinium cation. The cytosinium cation forms a C(6) chain, while the zoledronate anion forms a rectangular‐shaped centrosymmetric dimer through N—H...O hydrogen bonds. The cations and anions are held together by N—H...O and O—H...O hydrogen bonds to form a one‐dimensional polymeric tape. The three water molecules play a crucial role in hydrogen bonding, resulting in a three‐dimensional hydrogen‐bonded network.