2‐Benzyl­amino‐6‐benzyl­oxy­pyrimidin‐4(3H)‐one: hydrogen‐bonded chains of rings linked into sheets by a π–π‐stacking interaction

The title compound, C₁₈H₁₇N₃O₂, crystallizes with Z′ = 2 in space group P2₁/c, and the two independent mol­ecules are approximate, but not exact, mirror images. The molecular–electronic structure is strongly polarized, and the mol­ecules are linked by paired N—H⃛O hydrogen bonds [H⃛O = 2.00–2.23 Å, N⃛O = 2.798 (3)–2.992 (3) Å and N—H⃛O = 145–151°] into two independent C(4)C(6)[(6)] chains of rings, which are linked into sheets by a single aromatic π–π‐stacking interaction.     

Triclinic and orthorhombic polymorphs of 2‐iodo‐4‐nitro­aniline: interplay of hydrogen bonds,nitro⃛I interactions and aromatic π–π‐stacking interactions

In the triclinic polymorph of 2‐iodo‐4‐nitro­aniline, C₆H₅IN₂O₂, space group P, the mol­ecules are linked by paired N—­H?O hydrogen bonds into C(8)[R(6)] chains of rings. These chains are linked into sheets by nitro?I interactions, and the sheets are pairwise linked by aromatic π–π‐stacking interactions. In the orthorhombic polymorph, space group Pbca, the mol­ecules are linked by single N—H?O hydrogen bonds into spiral C(8) chains; the chains are linked by nitro?O interactions into sheets, each of which is linked to its two immediate neighbours by aromatic π–π‐stacking inter­actions, so producing a continuous three‐dimensional ­structure.     

Hydrogen bonding in nitroaniline analogues: hydrogen‐bonded sheets in 2‐amino‐4,6‐dimethoxy‐5‐nitropyrimidine and π‐stacked hydrogen‐bonded sheets in 4‐amino‐2,6‐dimethoxy‐5‐nitropyrimidine

In 2‐amino‐4,6‐di­methoxy‐5‐nitro­pyrimidine, C₆H₈N₄O₄, the mol­ecules are linked by one N—H⋯N and one N—H⋯O hydrogen bond to form sheets built from alternating R(8) and R(32) rings. In isomeric 4‐amino‐2,6‐di­methoxy‐5‐nitro­pyrimidine, C₆H₈N₄O₄, which crystallizes with Z′ = 2 in P, the two independent mol­ecules are linked into a dimer by two independent N—H⋯N hydrogen bonds. These dimers are linked into sheets by a combination of two‐centre C—H⋯O and three‐centre C—H⋯(O)₂ hydrogen bonds, and the sheets are further linked by two independent aromatic π–π‐stacking interactions to form a three‐dimensional structure.     

Hydrogen bonding in 2‐amino‐4,6‐dimethoxypyrimidine, 2‐benzylamino‐4,6‐bis(benzyloxy)pyrimidine and 2‐amino‐4,6‐bis(N‐pyrrolidino)pyrimidine: chains of fused rings and a centrosymmetric dimer

Molecules of 2‐amino‐4,6‐di­methoxy­pyrimidine, C₆H₉N₃O₂, (I), are linked by two N—H?N hydrogen bonds [H?N 2.23 and 2.50 Å, N?N 3.106 (2) and 3.261 (2) Å, and N—H?N 171 and 145°] into a chain of fused rings, where alternate rings are generated by centres of inversion and twofold rotation axes. Adjacent chains are linked by aromatic π–π‐stacking interactions to form a three‐dimensional framework. In 2‐­benzylamino‐4,6‐bis(benzyloxy)pyrimidine, C₂₅H₂₃N₃O₂, (II), the mol­ecules are linked into centrosymmetric R(8) dimers by paired N—H?N hydrogen bonds [H?N 2.13 Å, N?N 2.997 (2) Å and N—H?N 170°]. Molecules of 2‐amino‐4,6‐bis(N‐pyrrolidino)­pyrimidine, C₁₂H₁₉N₅, (III), are linked by two N—H?N hydrogen bonds [H?N 2.34 and 2.38 Å, N?N 3.186 (2) and 3.254 (2) Å, and N—H?N 163 and 170°] into a chain of fused rings similar to that in (I).     

1‐(6‐Amino‐1,3‐benzodioxol‐5‐yl)‐3‐(2‐oxo‐1,2‐dihydroquinolin‐3‐yl)prop‐2‐enone: a sheet built by π‐stacking of hydrogen‐bonded chains of rings

The bond distances in the molecule of the title compound, C₁₉H₁₄N₂O₄, provide evidence for electronic polarization in the aminoarylpropenone fragment and for bond fixation in the quinolinone unit. Molecules are linked by N—H...O and C—H...O hydrogen bonds into chains in which centrosymmetric rings of R₂²(8) and R₂²(18) types alternate, and these chains are linked into sheets by a single aromatic π–π stacking interaction.     

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.     

4‐Amino‐6‐benzyl­oxy‐2‐(methyl­sulfanyl)‐5‐nitro­so­pyrimidine: hydrogen‐bonded dimers linked into π‐stacked chains

The title compound, C₁₂H₁₂N₄O₂S, crystallizes with Z′ = 2 in space group P2₁/c. The intramolecular dimensions are consis­tent with a highly polarized electronic structure. Each of the independent mol­ecules forms a centrosymmetric dimer linked by paired N—H?N hydrogen bonds, and these dimers are linked into a single type of chain by aromatic π–π‐stacking interactions.     

Methyl 2‐benzamido‐4‐(3,4‐dimethoxyphenyl)‐5‐methylbenzoate and N‐{5‐benzoyl‐2‐[(Z)‐2‐methoxyethenyl]‐4‐methylphenyl}benzamide

Methyl 2‐benzamido‐4‐(3,4‐dimethoxyphenyl)‐5‐methylbenzoate, C₂₄H₂₃NO₅, (Ia), and N‐{5‐benzoyl‐2‐[(Z)‐2‐methoxyethenyl]‐4‐methylphenyl}benzamide, C₂₄H₂₁NO₃, (IIa), were formed via a Diels–Alder reaction of appropriately substituted 2H‐pyran‐2‐ones and methyl propiolate or (Z)‐1‐methoxybut‐1‐en‐3‐yne, respectively. Each of these cycloadditions might yield two different regioisomers, but just one was obtained in each case. In (Ia), an intramolecular N—H...O hydrogen bond closes a six‐membered ring. A chain is formed due to aromatic π–π interactions, and a three‐dimensional framework structure is formed by a combination of C—H...O and C—H...π(arene) hydrogen bonds. Compound (IIa) was formed not only regioselectively but also chemoselectively, with just the triple bond reacting and the double bond remaining unchanged. Compound (IIa) crystallizes as N—H...O hydrogen‐bonded dimers stabilized by aromatic π–π interactions. Dimers of (IIa) are connected into a chain by weak C—H...π(arene) interactions.     

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.     

(E)‐2‐(1,3‐Benzothiazol‐2‐yl)‐3‐(4‐fluorophenyl)acrylonitrile: a chain of π‐stacked hydrogen‐bonded rings

The title compound, C₁₆H₉FN₂S, crystallizes as a nonmerohedral twin with twin rotation about the reciprocal‐lattice vector [10]*. The molecules are nearly planar and the dihedral angle between the planes of the two aryl rings is only 4.4 (2)°. The molecules are linked by pairs of C—H...N hydrogen bonds to form cyclic centrosymmetric R₂²(18) dimers, which are linked into chains by an aromatic π–π stacking interaction. Comparisons are made with some related 3‐aryl‐2‐thienylacrylonitriles.     

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.     

2,3‐Dihydro‐3‐methyl‐2‐nitrimino‐1,3‐thiazole

The title compound {alternatively, 3‐methyl‐2‐[oxido(oxo)hydrazono]‐2,3‐dihydro‐1,3‐thiazole}, C₄H₅N₃O₂S, was obtained by methyl­ation of N‐(2‐thia­zolyl)­nitr­amine. The molecule lies on a mirror plane and the thia­zole ring is planar, regular in shape and aromatic. The S atom participates in the aromatic sextet via an electron pair on the 3p_z orbital. In the crystal, the mol­ecules are arranged in parallel layers, bound to each other by weak C—H?O and C—H?N hydrogen bonds and by S?O dipolar interactions, with an interlayer separation of 3.23 Å.     

5‐Nitro‐2,3‐bis(2‐pyridyl)­quinoxaline

In the crystal structure of the title compound, C₁₈H₁₁N₅O₂, two crystallographically independent mol­ecules having the same composition and cis–cis conformation (arrangement of the pyridyl rings) are observed. A C—H⃛N hydrogen bond links the centrosymmetrically related mol­ecules into a discrete pair [C⃛N = 3.462 (4) Å], and the structure is stabilized further by π–π‐stacking interactions between aromatic rings from two adjacent dimers.     

2,5‐Dimethyl‐6,7‐dihydrobenzo[h]pyrazolo[1,5‐a]quinazoline and 2‐tert‐butyl‐5‐methyl‐6,7‐dihydrobenzo[h]pyrazolo[1,5‐a]quinazoline

In both 2,5‐dimethyl‐6,7‐dihydrobenzo[h]pyrazolo[1,5‐a]quinazoline, C₁₆H₁₅N₃, (I), and 2‐tert‐butyl‐5‐methyl‐6,7‐dihydrobenzo[h]pyrazolo[1,5‐a]quinazoline, C₁₉H₂₁N₃, (II), which crystallizes with Z′ = 2 in the space group P, the non‐aromatic carbocyclic rings adopt screw‐boat conformations. The molecules of (I) are linked into chains of rings by a combination of C—H...N and C—H...π(arene) hydrogen bonds, while in (II) there are no hydrogen bonds of any kind.     

4‐[(3‐Chloro­phenyl)­diazenyl]‐2‐{[tris(hydroxy­methyl)­methyl]amino­methyl­ene}cyclo­hexa‐3,5‐dien‐1(2H)‐one

The title compound, C₁₇H₁₈ClN₃O₄, adopts the keto–amine tautomeric form and displays an intramolecular N—H⋯O hydrogen bond [N⋯O = 2.639 (2) Å]. The configuration around the azo N=N double bond is trans, and the dihedral angle between the planes of the two aromatic rings is 20.5 (2)°. The mol­ecules are linked by O—H⋯O hydrogen bonds to form a three‐dimensional network.     

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.     

4‐(2‐Hydroxyphenyl)‐2‐phenyl‐2,3‐dihydro‐1H‐1,5‐benzodiazepine and the 2‐(2,3‐dimethoxyphenyl)‐, 2‐(3,4‐dimethoxyphenyl)‐ and 2‐(2,5‐dimethoxyphenyl)‐substituted derivatives

The 1,5‐benzodiazepine ring system exhibits a puckered boat‐like conformation for all four title compounds [4‐(2‐hydroxyphenyl)‐2‐phenyl‐2,3‐dihydro‐1H‐1,5‐benzodiazepine, C₂₁H₁₈N₂O, (I), 2‐(2,3‐dimethoxyphenyl)‐4‐(2‐hydroxyphenyl)‐2,3‐dihydro‐1H‐1,5‐benzodiazepine, C₂₃H₂₂N₂O₃, (II), 2‐(3,4‐dimethoxyphenyl)‐4‐(2‐hydroxyphenyl)‐2,3‐dihydro‐1H‐1,5‐benzodiazepine, C₂₃H₂₂N₂O₃, (III), and 2‐(2,5‐dimethoxyphenyl)‐4‐(2‐hydroxyphenyl)‐2,3‐dihydro‐1H‐1,5‐benzodiazepine, C₂₃H₂₂N₂O₃, (IV)]. The stereochemical correlation of the two C₆ aromatic groups with respect to the benzodiazepine ring system is pseudo‐equatorial–equatorial for compounds (I) (the phenyl group), (II) (the 2,3‐dimethoxyphenyl group) and (III) (the 3,4‐dimethoxyphenyl group), while for (IV) (the 2,5‐dimethoxyphenyl group) the system is pseudo‐axial–equatorial. An intramolecular hydrogen bond between the hydroxyl OH group and a benzodiazepine N atom is present for all four compounds and defines a six‐membered ring, whose geometry is constant across the series. Although the molecular structures are similar, the supramolecular packing is different; compounds (I) and (IV) form chains, while (II) forms dimeric units and (III) displays a layered structure. The packing seems to depend on at least two factors: (i) the nature of the atoms defining the hydrogen bond and (ii) the number of intermolecular interactions of the types O—H...O, N—H...O, N—H...π(arene) or C—H...π(arene).     

3‐[(E)‐(3‐tert‐Butyl‐1‐phenyl‐1H‐pyrazol‐5‐yl)iminomethyl]quinolin‐2(1H)‐one: chains built by π‐stacking of hydrogen‐bonded R22(8) dimers

In the title compound, C₂₃H₂₂N₄O, there is evidence for some bond fixation in the aryl component of the quinolinone unit. Pairs of molecules related by inversion are linked into R₂²(8) dimers by almost linear N—H...O hydrogen bonds, and dimers related by inversion are linked into chains by a single aromatic π–π stacking interaction.     

meso‐5,5,7,12,12,14‐Hexamethyl‐1,4‐diaza‐8,11‐diazoniacyclotetradecane bis(2‐naphthoate) ethanol disolvate: centrosymmetric five‐component aggregates linked into sheets by C—H⃛π(arene) hydrogen bonding

The title compound is an ethanol‐solvated salt, C₁₆H₃₈N₄²⁺·2C₁₁H₇O₂⁻·2C₂H₆O, in which the cation lies across a centre of inversion in P2₁/c. The ions are linked by N—H⃛O hydrogen bonds [H⃛O = 1.70 and 2.30 Å, N⃛O = 2.624 (2) and 3.136 (2) Å, and N—H⃛O = 178 and 151°], and the ethanol mol­ecule is linked to the anion by an O—H⃛O hydrogen bond [H⃛O = 1.90 Å, O⃛O = 2.728 (2) Å and O—H⃛O = 171°], to form a centrosymmetric five‐component aggregate. C—H⃛O hydrogen bonds and aromatic π–π‐stacking interactions are absent, but the aggregates are linked into sheets by a single C—H⃛π(arene) hydrogen bond.     

2‐Iodo‐N‐(3‐nitrobenzyl)aniline and 3‐iodo‐N‐(3‐nitrobenzyl)aniline exhibit entirely different patterns of supramolecular aggregation

In 2‐iodo‐N‐(3‐nitro­benzyl)­aniline, C₁₃H₁₁IN₂O₂, the mol­ecules are linked into a three‐dimensional structure by a combination of C—H?O hydrogen bonds, iodo–nitro interactions and aromatic π–π‐stacking interactions, but N—H?O and C—H?π(arene) hydrogen bonds are absent. In the isomeric 3‐iodo‐N‐(3‐nitro­benzyl)­aniline, a two‐dimensional array is generated by a combination of N—H?O, C—H?O and C—H?π(arene) hydrogen bonds, but iodo–nitro interactions and aromatic π–π‐stacking interactions are both absent.