3-Nitro­benzaldehyde isonicotinoyl­hydrazone monohydrate redetermined at 120 K: sheets built from O-H...O, O-H...N, N-H...O and C-H...O hydrogen bonds

In the title compound, C₁₃H₁₀N₄O₃·H₂O, the mol­ecular components are linked into complex sheets by a combination of four types of hydrogen bonds.

2,3-Dimethoxy­benzaldehyde isonicotinoyl­hydrazone chloro­form monosolvate, and the mono- and dihydrates of 3,4,5-trimethoxy­benzaldehyde isonicotinoyl­hydrazone: hydrogen-bonded supra­molecular structures in one, two and three dimensions

In 2,3-dimethoxy­benzaldehyde isonicotinoyl­hydrazone chloro­form monosolvate, C₁₅H₁₅N₃O₃·CHCl₃, the hydrazone mol­ecules are linked by a combination of N—H...N and C—H...N hydrogen bonds into chains from which the chloro­form mol­ecules are pendent. 3,4,5-Trimethoxy­benzaldehyde isonicotinoyl­hydrazone forms two stoichiometric hydrates. In the monohydrate, C₁₆H₁₇N₃O₄·H₂O, the components are linked into sheets by a combination of O—H...O, O—H...N and N—H...N hydrogen bonds, and in the dihydrate, C₁₆H₁₇N₃O₄·2H₂O, a combination of O—H...O, O—H...N and N—H...O hydrogen bonds links the components into a three-dimensional framework structure.

4-Cyano­benzaldehyde isonicotinoylhydrazone monohydrate: a three-dimensional hydrogen-bonded ­framework structure

In the title compound, C₁₄H₁₀N₄O·H₂O, the mol­ecular components are linked into a three-dimensional framework by three hydrogen bonds, one each of the O—H...O, O—H...N and N—H...O types, weakly augmented by two C—H...O hydrogen bonds.

A re-examination of supra­molecular aggregation in two polymorphs of acetone 2,4-dinitro­phenyl­hydrazone

The structure of the triclinic polymorph of acetone 2,4-dinitrophenylhydrazone, C₉H₁₀N₄O₄, has been redetermined from diffraction data collected at 120 (2) K; the mol­ecules are linked by C-H...O hydrogen bonds into centrosymmetric R₂²(10) dimers which are themselves linked into a chain by an aromatic [pi]-[pi] stacking inter­action. In the monoclinic polymorph, which crystallizes with Z' = 2 in the space group P2₁/n, one type of mol­ecule forms dimers exactly as in the triclinic polymorph, while the other forms C(6) 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 [pi]-[pi] stacking inter­actions.

N-(4-Nitro­benzo­yl)-N'-phenyl­hydrazine: a three-dimensional hydrogen-bonded framework

In the title compound (systematic name: N-anilino-4-nitro­benzamide), C₁₃H₁₁N₃O₃, the mol­ecules are linked into a complex three-dimensional framework structure by a combination of two-centre N-H...O and C-H...O hydrogen bonds and a three-centre N-H...(O,N) hydrogen bond.

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.

Cyclic and acyclic products from the reactions between methyl 3-oxo­butanoate and aryl­hydrazines

The mol­ecules of methyl 3-(2-nitro­phenyl­hydrazono)­butan­oate, C₁₁H₁₃N₃O₄, (I), and methyl 3-(2,4-dinitro­phenyl­hydrazono)butanoate, C₁₁H₁₂N₄O₆, (II), both prepared from methyl 3-oxobutanoate and the corresponding nitro­phenyl­hydrazine, exhibit polarized mol­ecular electronic structures; in each of (I) and (II), the mol­ecules are linked into chains by a single C-H...O hydrogen bond. The mol­ecules of 5-hydroxy-3-methyl-1-phenyl-1H-pyrazole, C₁₀H₁₀N₂O, (III), prepared by the reaction of methyl 3-oxobutanoate and phenyl­hydrazine, are linked into chains by a single O-H...N hydrogen bond. The reaction between methyl 3-oxobutanoate and 3-nitro­phenyl­hydrazine yields 5-hydr­oxy-3-methyl-1-(3-nitro­phen­yl)-1H-pyrazole, (IV), which when crystallized from acetone yields 4-isopropyl­idene-3-methyl-1-(3-nitro­phen­yl)-1H-pyrazol-5(4H)-one, C₁₃H₁₃N₃O₃, (V).

π-Stacked dimers in 6-meth­oxy-3,3-dimethyl-3H-benzo[f]chromene, and centrosymmetric dimers containing C—H...π(arene) hydrogen bonds in racemic 3-bromo-2,2,6,6-tetra­methyl-3,4-dihydro-2H,6H-1,5-dioxa­triphenyl­ene

The title compounds, namely 6-meth­oxy-3,3-dimethyl-3H-benzo[f]chromene, C₁₆H₁₆O₂, (III), and racemic 3-bromo-2,2,6,6-tetra­methyl-3,4-dihydro-2H,6H-1,5-dioxatriphenyl­ene, C₂₀H₂₁BrO₂, (IV), were both synthesized in one-step regioselective Wittig reactions from substituted 1,2-naphthoquinones. The new ring in both compounds adopts a screw-boat conformation. A single π–π stacking inter­action links the mol­ecules of (III) into centrosymmetric dimeric aggregates, and a single C—H...π(arene) hydrogen bond links the mol­ecules of (IV) into centrosymmetric dimers.