Pentazol‐Derivate und daraus entstehende Azide: [O3S—p‐C6H4—N5]— und [O3S—p‐C6H4—N3]— als Kalium‐Kronenether‐Salze

Pentazole Derivates and Azides Formed from them: Potassium‐Crown‐Ether Salts of [O₃S—p‐C₆H₄—N₅]^— and [O₃S—p‐C₆H₄—N₃]^{— —}O₃S—p‐C₆H₄—N₂⁺ was reacted with sodium azide at —50 °C in methanol, yielding a mixture of 4‐pentazolylbenzenesulfonate and 4‐azidobenzenesulfonate (amount‐of‐substance ratio 27:73 according to NMR). By addition of KOH in methanol at —50 °C a mixture of the potassium salts K[O₃S—p‐C₆H₄—N₅] and K[O₃S—p‐C₆H₄—N₃] was precipitated (ratio 60:40). A solution of this mixture along with 18‐crown‐6 in tetrahydrofurane yielded the crystalline pentazole derivate [THF‐K‐18‐crown‐6][O₃S—p‐C₆H₄—N₅]·THF by addition of petrol ether at —70 °C. From the same solution upon evaporation and redissolution in THF/petrol ether the crystalline azide [THF‐K‐18‐crown‐6][O₃S—p‐C₆H₄—N₃]·THF was obtained. A solution of the latter in chloroform/toluene under air yielded [K‐18‐crown‐6][O₃S—p‐C₆H₄—N₃]·1/3H₂O. According to their X‐ray crystal structure determinations [THF‐K‐18‐crown‐6][O₃S—p‐C₆H₄—N₅]·THF and [THF‐K‐18‐crown‐6][O₃S—p‐C₆H₄—N₃]·THF have the same kind of crystal packing. Differences worth mentioning exist only for the atomic positions of the pentazole ring as compared to the azido group and for one THF molecule which is coordinated to the potassium ion; different orientations of the THF molecule take account for the different space requirements of the N₅ and the N₃ group. In [K‐18‐crown‐6][O₃S—p‐C₆H₄—N₃]·1/3H₂O there exists one unit consisting of one [K‐18‐crown‐6]⁺ and one [O₃S‐C₆H₄—N₃]^— ion and another unit consisting of two [O₃S‐C₆H₄—N₃]^— ions joined via two [K‐18‐crown‐6]⁺ ions and one water molecule. The rate constants for the decomposition [O₃S‐C₆H₄—N₅]^— → [O₃S‐C₆H₄—N₃]^— + N₂ in methanol were determined at 0 °C and —20 °C.     

Soluble polymers with pendant 3‐en‐1‐yne groups (R) on a —[CH2—C(Me)R]n— skeleton by anionic polymerization of 2,5‐dimethylhexa‐1,5‐dien‐3‐yne

The anionic homopolymerization of 2,5‐dimethylhexa‐1.5‐dien‐3‐yne (DMDEY) was investigated by utilizing butyllithium, sec‐butyllithium, diphenylmethylsodium, and naphthalene/sodium as initiators. Soluble polymers with molecular weights up to 50 000 g/mol corresponding to M_w/M_n of 1.05 were obtained through homopolymerization with diphenylmethylsodium as initiator in THF at low temperatures. The homopolymers consist of 1,2‐linked monomer units with pendant 3‐methylbut‐3‐en‐1‐yne groups.     

C—H...O hydrogen‐bonding and C—H...π interactions in 3‐(4‐fluorophenyl)‐1,5,7‐trimethyl‐1,2,3,4‐tetrahydropyrido[2,3‐d]pyrimidine‐2,4‐dione

In the title compound, C₁₆H₁₄FN₃O₂, a diverse set of weak intermolecular C—H...π, π–π and C—H...O interactions link the molecules into sheets. The C—H...O interactions generate centrosymmetric rings with a graph‐set motif of R₂²(14) and chains with a C(8) motif.     

Octyl 1‐(5‐tert‐butyl‐1H‐pyrazol‐3‐yl)‐2‐(4‐chlorophenyl)‐1H‐benzimidazole‐5‐carboxylate: complex sheets built from N—H...N,C—H...N and C—H...O hydrogen bonds

In the title compound, C₂₉H₃₅ClN₄O₂, the bond lengths provide evidence for aromatic delocalization in the pyrazole ring but bond fixation in the fused imidazole ring, and the octyl chain is folded, rather than adopting an all‐trans chain‐extended conformation. A combination of N—H...N, C—H...N and C—H...O hydrogen bonds links the molecules into sheets, in which the hydrogen bonds occupy the central layer with the tert‐butyl and octyl groups arranged on either side, such that the closest contacts between adjacent sheets involve only the octyl groups. Comparisons are made with the supramolecular assembly in some simpler analogues.     

1,4‐Diphenyl‐1,4‐di‐4‐pyridyl‐2,3‐diaza‐1,3‐butadiene: weak C—H·N and C—H·π hydrogen bonds

In the title compound, C₂₄H₁₈N₄, each Schiff base molecule is centrosymmetric and interacts with four neighbours via four C—H(Ph)·N(py) hydrogen bonds (py is pyridyl) and four C—H(py)·π(Ph) hydrogen bonds, leading to an interesting two‐dimensional hydrogen‐bonded layer architecture.     

C—H⋯N and C—H⋯π interactions in 2‐ethoxy‐4,6‐diphenylpyridine‐3‐carbonitrile

The title compound, C₂₀H₁₆N₂O, has two mol­ecules in the asymmetric unit and the crystal structure shows that the central pyridine ring of each mol­ecule has a flat boat conformation. The terminal C atom in one of the mol­ecules is disordered over two positions, with relative occupancies of 0.594 (14) and 0.398 (14). Intermolecular C—H?N and C—H?π interactions and π–π stacking, along with intramolecular C—H?N and C—H?π interactions, help to stabilize the structure.     

4‐(2‐Fluorophenyl)‐6‐(1H‐indol‐1‐yl)‐3‐methyl‐1‐phenyl‐1H‐pyrazolo[3,4‐b]pyridine‐5‐carbonitrile: a chain of rings built from N—H...N,C—H...N and C—H...π(arene) hydrogen bonds

In the title compound, C₂₈H₁₈FN₅, molecules are linked by a combination of N—H...N, C—H...N and C—H...π(arene) hydrogen bonds into complex double chains. The chains enclose cavities, four per unit cell, each of volume ca 102 ų and apparently containing disordered solvent.     

Dimers linked by type‐I C—F...F—C contacts in (Z)‐3‐methyl‐4‐[2‐(4‐methylphenyl)hydrazinylidene]‐1‐(pentafluorophenyl)‐1H‐pyrazol‐5(4H)‐one

The title compound, C₁₇H₁₁F₅N₄O, is described and compared with two closely related analogues in the literature. There are two independent molecules in the asymmetric unit, linked by N—H...O hydrogen bonds and π–π interactions into dimeric entities, presenting a noticeable noncrystallographic C₂ symmetry. These dimers are in turn linked by a medium‐strength type‐I C—F...F—C interaction into elongated tetramers. Much weaker C—H...F contacts link the tetramers into broad two‐dimensional substructures parallel to (101).     

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.     

1‐(2‐Aminophenyl)‐3‐(4‐pyridyl)prop‐2‐en‐1‐one: a three‐dimensional framework structure built from N—H...N,C—H...O and C—H...π(arene) hydrogen bonds

The intramolecular dimensions of the title compound, C₁₄H₁₂N₂O, provide evidence for a polarized electronic structure. The molecule, which is almost completely planar, contains an intramolecular N—H...O hydrogen bond, and the molecules are linked by a combination of N—H...N, C—H...O and C—H...π(arene) hydrogen bonds to form a three‐dimensional framework structure.     

Intermolecular C—H...π interactions in 1,5‐diphenyl‐3‐(2‐pyridyl)‐2‐pyrazoline

The title compound, C₂₀H₁₇N₃, is a derivative of 1,3,5‐triaryl‐2‐pyrazoline and can act as an N,N′‐bidentate ligand. This molecule features strong fluorescence that can be explained by an extended pyridyl–C=N—N–phenyl system. The three‐dimensional structure is formed by means of an extended network of weak C—H...π hydrogen bonds supported by π–π interactions.     

1‐Arylsulfonyl‐2‐styrylsulfonylthenes — source for a new class of bis heterocycles

New and novel sulfone linked bis heterocycles_ bis pyrroles and pyrrolyl pyrazolines are prepared from 1‐arylsulfonyl‐2‐styrylsulfonylethenes by 1,3‐dipolar cycloaddition methodology.     

2‐(4‐Chlorophenyl)‐5‐(4‐nitrophenyl)‐4,7‐dihydropyrazolo[1,5‐a]pyrimidine‐3,6‐dicarbaldehyde: a chain of rings built from N—H...O and C—H...O hydrogen bonds

In the title compound, C₂₀H₁₃ClN₄O₄, the six‐membered heterocyclic ring is planar and the molecular dimensions provide evidence for polarization of the molecular–electronic structure. Molecules are linked into a chain of rings by a combination of N—H...O and C—H...O hydrogen bonds, but the nitro group does not participate in the supramolecular aggregation. This study illustrates the marked influence of peripheral substituents on the pattern of hydrogen‐bonded aggregation in compounds of this type.     

5‐Chloro‐2‐hydroxybenzophenone,featuring O—H...O,C—H...O,C—H...π and π–π interactions

Molecules of the title compound, C₁₃H₉ClO₂, contain an intramolecular O—H...O hydrogen bond, and the two aromatic rings are inclined at 57.02 (3)° with respect to one another. The crystal structure is supported by C—H...O, C—H...π and π–π interactions.