2,4‐Di­nitro­phenyl­hydrazones of 2,4‐di­hydroxy­benz­aldehyde, 2,4‐di­hydroxy­aceto­phenone and 2,4‐di­hydroxy­benzo­phenone

In 2,4‐di­hydroxy­benz­aldehyde 2,4‐di­nitro­phenyl­hydrazone N,N‐di­methyl­form­amide solvate {or 4‐[(2,4‐di­nitro­phenyl)­hydrazono­methyl]­benzene‐1,3‐diol N,N‐di­methyl­form­amide solvate}, C₁₃H₁₀N₄O₆·C₃H₇NO, (X), 2,4‐di­hydroxy­aceto­phenone 2,4‐di­nitro­phenyl­hydrazone N,N‐di­methyl­form­am­ide solvate (or 4‐{1‐[(2,4‐di­nitro­phenyl)hydrazono]ethyl}benzene‐1,3‐diol N,N‐di­methyl­form­amide solvate), C₁₄H₁₂N₄O₆·C₃H₇NO, (XI), and 2,4‐di­hydroxy­benzo­phenone 2,4‐di­nitro­phenyl­hydrazone N,N‐di­methyl­acet­amide solvate (or 4‐­{[(2,4‐di­nitro­phenyl)hydrazono]phenyl­methyl}benzene‐1,3‐diol N,N‐di­methyl­acet­amide solvate), C₁₉H₁₄N₄O₆·C₄H₉NO, (XII), the molecules all lack a center of symmetry, crystallize in centrosymmetric space groups and have been observed to exhibit non‐linear optical activity. In each case, the hydrazone skeleton is fairly planar, facilitated by the presence of two intramolecular hydrogen bonds and some partial N—N double‐bond character. Each molecule is hydrogen bonded to one solvent mol­ecule.     

Supramolecular structures of 5‐[3‐(4‐methyl­phenyl)‐ and 5‐[3‐(4‐chloro­phenyl)‐2‐propenyl­idene]‐2,2‐di­methyl‐1,3‐dioxane‐4,6‐dione

2,2‐Di­methyl‐5‐[3‐(4‐methyl­phenyl)‐2‐propenyl­idene]‐1,3‐di­ox­ane‐4,6‐dione, C₁₆H₁₆O₄, crystallizes in the triclinic space group , with two mol­ecules in the asymmetric unit. These mol­ecules and a centrosymmetrically related pair, linked together by weak C—H?O hydrogen bonds, form a tetramer. 5‐[3‐(4‐Chloro­phenyl)‐2‐propenyl­idene]‐2,2‐di­methyl‐1,3‐dioxane‐4,6‐dione, C₁₅H₁₃ClO₄, also crystallizes in the triclinic space group , with one mol­ecule in the asymmetric unit. Centrosymmetrically related mol­ecules are linked together by weak C—H?O hydrogen bonds to form dimers which are further linked by yet another pair of centrosymmetrically related C—H?O hydrogen bonds to form a tube which runs parallel to the a axis.     

Two 5‐oxa‐2,6‐diazaspiro[3.4]octan‐1‐one derivatives from the [3+2] cyclo­addition of methylenelactams with nitrones

The two title 5‐oxa‐2,6‐di­aza­spiro­[3.4]­octan‐1‐one adducts, 7‐benzoyl‐2‐(4‐methoxy­phenyl)‐6‐phenyl‐5‐oxa‐2,6‐di­aza­spiro­[3.4]­octan‐1‐one, C₂₅H₂₂N₂O₄, (III), and 6‐tert‐butyl‐2‐(4‐methyl­phenyl)‐7‐phenyl‐5‐oxa‐2,6‐di­aza­spiro­[3.4]­octan‐1‐one, C₂₂H₂₆N₂O₂, (IV), were obtained from a stereospecific [3+2] 1,3‐cyclo­addition of 3‐methyl­ene azetidin‐2‐ones as dipolaro­philes with nitro­nes. The lactam ring is conjugated with the p‐­methoxy­phenyl or p‐methyl­phenyl moiety. The envelope conformations of the isoxazolidine rings in (III) and (IV) are different, leading the substituents to be pseudo‐axial in (III) and pseudo‐equatorial in (IV).     

Charge‐transfer complexes of 4‐(di­methyl­amino)­pyridine with 2,4‐, 3,4‐ and 3,5‐di­nitro­benzoic acid

In the three title crystal structures 4‐(di­methyl­amino)­pyridinium 2,4‐di­nitro­benzoate, (I), 4‐(di­methyl­amino)­pyri­dinium 3,4‐di­nitro­benzo­ate, (II), and 4‐(di­methyl­amino)pyri­din­ium 3,5‐di­nitro­benzo­ate, (III), all C₇H₁₁N₂⁺·C₇H₃N₂O₆^?, the ions are connected by an N—H?O hydrogen bond. Dihedral angles between the pyridine and phenyl rings are 69.9 (1), 26.7 (1) and 56.2 (1)° in (I), (II) and (III), respectively. Donor–acceptor π–π stacking is observed in (II) and (III), but not in (I).     

Azole. 45.

The three title compounds, namely (Z)‐1‐(4,5‐di­nitro­imidazol‐1‐yl)‐3‐morpholinopropan‐2‐one 2,4‐di­nitro­phenyl­hydrazone, C₁₆H₁₇N₉O₉, (IV), (Z)‐3‐morpholino‐1‐(4‐morpholino‐5‐nitro­imidazol‐1‐yl)propan‐2‐one 2,4‐di­nitro­phenyl­hydrazone, C₂₀H₂₅N₉O₈, (Va), and (E)‐3‐morpholino‐1‐(4‐morpholino‐5‐nitro­imidazol‐1‐yl)propan‐2‐one 2,4‐di­nitro­phenylhydra­zone tetra­hydro­furan solvate, C₂₀H₂₅N₉O₈·C₄H₈O, (Vb), have been prepared and their structures determined. In (IV), the C‐4 nitro group is nearly perpendicular to the imidazole ring and the C‐4—NO₂ bond length is comparable to the value for a normal single Csp²—NO₂ bond. In (IV), (Va) and (Vb), the C‐­5 nitro group deviates insignificantly from the imidazole plane and the C‐5—NO₂ bond length is far shorter in all three compounds than C‐4—NO₂ in (IV). In consequence, the C‐4 nitro group in (IV) is easily replaced by morpholine, while the C‐5 nitro group in (IV), (Va) and (Vb) shows an extraordinary stability on treatment with the amine. The E configuration in (Vb) is stabilized by a three‐centre hydrogen bond.     

Packing considerations of bis‐dimedone derivatives

We have determined the crystal structures of 2,2′‐(4‐fluoro­phenyl)­methyl­enebis(3‐hydroxy‐5,5‐di­methyl‐2‐cyclo­hexen‐1‐one), C₂₃H₂₇FO₄, (I), 2,2′‐(4‐chloro­phenyl)­methyl­enebis(3‐hy­droxy‐5,5‐dimethyl‐2‐cyclo­hexen‐1‐one), C₂₃H₂₇ClO₄, (II), 2,2′‐(4‐hydroxy­phenyl)­methyl­enebis(3‐hydroxy‐5,5‐di­methyl‐2‐cyclo­hexen‐1‐one), C₂₃H₂₈O₅, (III), 2,2′‐(4‐methyl­phenyl)­methyl­enebis(3‐hydroxy‐5,5‐di­methyl‐2‐cyclo­hexen‐1‐one), C₂₄H₃₀O₄, (IV), 2,2′‐(4‐methoxy­phenyl)­methyl­enebis(3‐hy­droxy‐5,5‐di­methyl‐2‐cyclo­hexen‐1‐one), C₂₄H₃₀O₅, (V), and 2,2′‐(4‐N,N′‐di­methyl­amino­phenyl)­methyl­enebis(3‐hydroxy‐5,5‐di­methyl‐2‐cyclo­hexen‐1‐one), C₂₅H₃₃NO₄, (VI). Structures (III) to (VI) of these bis‐dimedone derivatives show nearly the same packing pattern irrespective of the different substituent in the para position of the aromatic ring. However, (II) does not fit into this scheme, although the Cl atom is a substituent not too different from the others. The different packing of the fluoro compound, (I), can be explained by the fact that it crystallizes with two mol­ecules in the asymmetric unit, which show a different conformation of the dimedone ring. On the other hand, (I) shows a similar packing pattern to bis(2‐hydroxy‐4,4‐di­methyl‐6‐oxo‐1‐cyclo­hexenyl)­phenyl­methane, a compound containing an aromatic ring without any substituent and with Z′ = 2.     

2‐Amino derivatives of 5‐nitro­phenyl­acet­amide

The structures of the potential non‐linear optical (NLO) materials N‐[2‐(iso­propyl­amino)‐5‐nitro­phenyl]­acet­amide, (I) C₁₁H₁₅N₃O₃, and N‐[2‐(butyl­amino)‐5‐nitro­phenyl]­acet­amide, (II) C₁₂H₁₇N₃O₃, have been investigated by X‐ray analysis. To compare them with the structure of N‐[2‐(di­methyl­amino)‐5‐nitro­phenyl]­acet­amide, (III) C₁₀H₁₃N₃O₃, a known NLO compound, we had to redetermine the structure of (III), since it was described only briefly in the literature. There are two mol­ecules in the asymmetric unit of compound (I), which have different orientations of the substituents with respect to the benzene ring. The packing of mol­ecules in (II) and (III) contains stacks but both (I) and (II) crystallize in a centrosymmetric space group, which renders them inappropriate for NLO applications.     

N,N′‐Bis(2‐methoxy­benzyl­idene) adducts of ethane‐1,2‐di­amine,propane‐1,3‐di­amine and butane‐1,4‐di­amine

We have isolated and crystallographically characterized the three homologous compounds N,N′‐bis(2‐methoxy­benzyl­idene)­ethane‐1,2‐di­amine (MeSalen), C₁₈H₂₀N₂O₂, N,N′‐bis(2‐methoxy­benzyl­idene)­propane‐1,3‐di­amine (MeSalpr), C₁₉H₂₂N₂O₂, and N,N′‐bis(2‐methoxy­benzyl­idene)­butane‐1,4‐di­amine (MeSalbu), C₂₀H₂₄N₂O₂. In contrast with MeSalpr, the mol­ecules of MeSalen and MeSalbu, which have an even number of methyl­ene units, have crystallographic symmetry. Comparing these methoxy‐substituted species with their hydroxy equivalents shows that the aryl rings rotate upon removal of the O—H⋯N hydrogen bonds. The packing of MeSalen and MeSalpr is controlled by C—H⋯π interactions, whereas that of MeSalbu has only van der Waals contacts.     

4‐Methyl‐2‐[N‐(3,4‐methyl­ene­dioxy­benzyl­idene)hydrazino]­thia­zole and its reduction product, 4‐methyl‐2‐[N‐(3,4‐methyl­ene­dioxybenzyl­idene)hydrazono]‐4,5‐di­hydro­thia­zole

The crystal structures of 4‐methyl‐2‐[N‐(3,4‐methyl­ene­dioxybenzyl­idene)hydrazino]­thia­zole, C₁₂H₁₁N₃O₂S, and its reduction product 4‐methyl‐2‐[N‐(3,4‐methyl­ene­dioxybenzyl­idene)hydrazono]‐4,5‐di­hydro­thia­zole, C₁₂H₁₃N₃O₂S, have been determined and compared. In the reduction product, the tautomer observed bears an H atom on the exocyclic N atom. Both compounds form hydrogen‐bonded dimers over centers of inversion.     

Charge‐transfer complexes of N‐methyl‐and N‐ethyl­carbazole with 3,5‐di­nitro­benzo­nitrile

In the two title compounds, N‐methyl­carba­zole–3,5‐di­nitro­benzo­nitrile (1/1), C₁₃H₁₁N·C₇H₃N₃O₄, (I), and N‐ethyl­carba­zole–3,5‐di­nitro­benzo­nitrile (1/1), C₁₄H₁₃N·C₇H₃N₃O₄, (II), the donor and acceptor mol­ecules are stacked alternately to form one‐dimensional columns. In (I), the N‐methyl group of the donor is nearly eclipsed with respect to one of the nitro groups of the neighboring acceptor in a column, whereas the N‐ethyl group is anti with respect to the cyano group of the neighboring acceptor in (II).     

Intermolecular interactions and ­molecular geometry in molecular complexes of N,N‐di­methyl­aniline: the 1:1 complex with 1,2,4,5‐tetra­cyano­benzene

The partner mol­ecules of N,N‐di­methyl­aniline–1,2,4,5‐tetra­cyano­benzene (1/1), C₈H₁₁N·C₁₀H₂N₄, are stacked alternately in infinite columns. The N atom of the N,N‐di­methyl­aniline mol­ecule has a partially tetrahedral character and the distance between neighbouring mol­ecules in the stack is relatively short on the side where the lone‐pair electrons of this atom are located. Molecular‐packing analysis of this and three other complexes of N,N‐di­methyl­aniline shows that there is a close relationship between the strength of the intermolecular interaction on this side and the tetrahedral character of the N atom.     

Bis(2,5‐dimethoxy‐4‐methylphenyl)methane and bis(2,5‐dimethoxy‐3,4,6‐trimethylphenyl)methane

Bis(2,5‐di­methoxy‐4‐methyl­phenyl)­methane, C₁₉H₂₄O₄, (IIa), was obtained and characterized as a minor product from the reaction of tolu­hydro­quinone di­methyl ether (1,4‐dimethoxy‐2‐methylbenzene) with N‐(hydroxy­methyl)­tri­fluoro­acet­amide. Similarly, bis(2,5‐di­methoxy‐3,4,6‐tri­methyl­phenyl)­methane, C₂₃H₃₂O₄, (IIb), was prepared from the corresponding reaction of tri­methyl­hydro­quinone di­methyl ether (2,5‐dimethoxy‐1,3,4‐trimethylbenzene). The mol­ecules of (IIa) and (IIb) each lie on a twofold axis passing through the methyl­ene group. The dihedral angle between the planar phenyl rings is 73.4 (1)° in (IIa) and 77.9 (1)° in (IIb). The external bond angles around the bridging methyl­ene group are 116.6 (2) and 117.3 (2)° for (IIa) and (IIb), respectively. In (IIa), the methoxy substituents lie in the plane of the ring and are conjugated with the aromatic system, whereas in (IIb), they are almost perpendicular to the phenyl ring and are positioned on opposite sides.     

A benzopyran derivative substituted at position 3

In (E)‐3‐{[(di­phenoxy­phospho­ryl)­methyl­hydrazono]­methyl}‐4H‐1‐benzo­pyran‐4‐one, C₂₃H₁₉N₂O₅P, the benzo­pyran–methyl­hydrazone moiety is planar and the two phenoxy phenyl rings are inclined at angles of 21.29 (6) and 89.33 (5)°. Weak C—H?O and C—H?N intramolecular interactions exert some influence on the planarity and orientation of that moiety.     

Ranitidine hydro­chloride,a polymorphic crystal form

In the title compound, di­methyl­({5‐[2‐(1‐methyl­amino‐2‐nitro­eth­enyl­amino)­ethyl­thio­methyl]‐2‐furyl}­methyl)­ammon­ium chloride, C₁₃H₂₃N₄O₃S⁺·­Cl^?, protonation occurs at the di­methyl­amino N atom. The ranitidine mol­ecule adopts an eclipsed conformation. Bond lengths indicate extensive electron delocalization in the N,N′‐di­methyl‐2‐nitro‐1,1‐ethenedi­amine system of the mol­ecule. The nitro and methyl­amino groups are trans across the side chain C=C double bond, while the ethyl­amino and nitro groups are cis. The Cl^? ions link mol­ecules through hydrogen bonds.     

A combinatorial chemistry approach to new materials for non‐linear optics. II. 4‐(Dimethylamino)cinnamaldehyde and a molecular complex of ­4‐­methoxycinnamaldehyde with 2,4‐­dinitroaniline

The combinatorial chemistry approach has been used to synthesize an array of Schiff bases. The structures of five of these Schiff bases have been confirmed by X‐ray analysis [Nesterov, Timofeeva, Borbulevych, Antipin & Clark (2000). Acta Cryst. C 56 , 971–975]. In two cases, the reaction conditions were not sufficient to obtain the products in question. In one case, a molecular complex, C₁₀H₁₀O₂·­C₆H₅N₃O₄, of the starting products 4‐methoxy­cinnam­aldehyde and 2,4‐di­nitro­aniline was found. X‐ray analysis revealed hydrogen‐bond formation between the mol­ecules of these reagents in the crystal. In the other case, X‐ray analysis demonstrated that no chemical reaction occurred under the reaction conditions, and only one starting reagent, 4‐(di­methyl­amino)­cinnam­aldehyde, C₁₁H₁₃NO, was found in the precipitate.     

[N,N′‐Bis(5‐bromo­salicyl­idene)‐o‐phenylene­diaminato]copper(II)

In the title compound, {4,4′‐di­bromo‐2,2′‐[o‐phenyl­ene­bis­(nitrilo­methyl­idene)]­di­phen­ol­ato‐O,N,N′,O′}copper(II), [Cu(C₂₀H₁₂Br₂N₂O₂], the Cu^II ion shows a slightly distorted square‐planar geometry with the N₂O₂ atoms of the Schiff base imine–phenol tetradentate ligand.     

3,5‐Di­fluoro‐4‐nitro­pyridine N‐oxide and 3,5‐di­amino‐4‐nitro­pyridine N‐oxide monohydrate

The mol­ecule of 3,5‐di­fluoro‐4‐nitro­pyridine N‐oxide, C₅H₂F₂N₂O₃, is twisted around the C—NO₂ bond by 38.5 (1)°, while the 3,5‐di­amino analogue, 3,5‐di­amino‐4‐nitro­pyridine N‐oxide monohydrate, C₅H₆N₄O₃·H₂O, adopts a planar conformation stabilized by intramolecular hydrogen bonds, with a significant redistribution of π electrons.     

Two orthopalladated chromophores

The title compounds, {5‐(di­methyl­amino)‐2‐[N‐(4‐methoxy­phenyl)­imino­methyl]­phenyl}[N‐(4‐methoxy­phenyl)‐4‐nitro­salicyl­aldiminato]­palladium(II), [Pd(C₁₄H₁₁N₂O₄)(C₁₆H₁₇N₂O)], (I), and [4‐(diethyl­amino)‐N‐(4‐methoxy­phenyl)­sali­cyl­aldiminato]{2‐[N‐(4‐methoxy­phenyl)­imino­methyl]‐5‐nitrophenyl}palladium(II) di­chloro­methane hemisolvate, [Pd(C₁₄H₁₁N₂O₃)(C₁₈H₂₁N₂O₂)]·0.5CH₂Cl₂, (II), both contain push–pull chromophores coordinated to Pd in a square‐planar arrangement. In both compounds, the five‐membered orthopalladated ring is essentially planar, while the coordinated six‐membered ring is not. Deviations from a coplanar arrangement of the phenyl­ene rings of the coordinated Schiff bases are observed in both (I) and (II) as a result of intramolecular steric interactions.     

[Hydroxy(aryl)methylene]diphos­phonic acids,a class of drugs in bone pathology treatments,crystallize as head‐to‐head dimers

Two [hydroxy­(aryl)­methyl­ene]­di­phospho­nic acids have been crystallized as dimers. The first compound, [hydroxy­(phenyl)­methyl­ene]­di­phospho­nic acid monohydrate, C₇H₁₀O₇P₂·H₂O, crystallizes in the non‐centrosymmetric space group P2₁, with the two enantiomers related by a non‐crystallographic centre of inversion, while the second compound, [hydroxy(4‐nitro­phenyl)­methyl­ene]­di­phospho­nic acid tetra­hydro­furan disolvate, C₇H₉NO₉P₂·2C₄H₈O, crystallizes in the centrosymmetric space group P2₁/c and uses the centre of symmetry to form the same dimer.     

[N,N′‐Bis­(salicyl­idene)‐2,2‐di­methyl‐1,3‐propane­diaminato]­nickel(II) and [N,N′‐bis­(salicyl­idene)‐2,2‐di­methyl‐1,3‐propane­diaminato]copper(II)

In the title compounds, {2,2′‐[2,2‐di­methyl‐1,3‐propane­diyl­bis­(nitrilo­methyl­idyne)]­diphenolato‐κ⁴N,N′,O,O′}nickel(II), [Ni(C₁₉H₂₀N₂O₂)], and {2,2′‐[2,2‐di­methyl‐1,3‐propane­diyl­bis­(nitrilo­methyl­idyne)]­diphenolato‐κ⁴N,N′,O,O′}copper(II), [Cu(C₁₉H₂₀N₂O₂)], the Ni^II and Cu^II atoms are coordinated by two iminic N and two phenolic O atoms of the N,N′‐bis­(salicyl­idene)‐2,2‐di­methyl‐1,3‐propane­diaminate (SALPD^2?, C₁₇H₁₆N₂O₂^2?) ligand. The geometry of the coordination sphere is planar in the case of the Ni^II complex and distorted towards tetrahedral for the Cu^II complex. Both complexes have a cis configuration imposed by the chelate ligand. The dihedral angles between the N/Ni/O and N/Cu/O coordination planes are 17.20 (6) and 35.13 (7)°, respectively.