The 1:1 adduct of hexa­methyl­ene­tetramine (HMT) with racemic trans‐1,2‐cyclo­hexane­di­carboxylic acid (CDA)

Hexa­methyl­ene­tetramine and rac‐trans‐1,2‐cyclo­hexane­di­carboxylic acid crystallize in a 1:1 ratio as a neutral molecular adduct, C₆H₁₂N₄·C₈H₁₂O₄. Two di­carboxylic acid mol­ecules and two tetr­amine mol­ecules form a hydrogen‐bonded ring, in the shape of a rhombus, which lies on a crystallographic twofold axis bisecting the two diacid mol­ecules. The O—H⋯N hydrogen bonds have lengths 2.6808 (19) and 2.6518 (19) Å, and, in each ring, both acid mol­ecules have the same handedness.     

Self‐assembly of 2‐pivaloyl‐6‐chloro­pterin

In the title compound, N‐(6‐chloro‐4‐oxo‐3,4‐di­hydro­pteridin‐2‐yl)­‐2,2‐di­methyl­propan­amide, C₁₁H₁₂ClN₅O₂, the rings in the pterin moiety are planar. The amide carbonyl O atom is in syn‐periplanar conformation while the C—N—C—C propanamide linkage is antiperiplanar. The N—H?N and N—H?O intermolecular hydrogen bonds transform the mol­ecules into infinite chains.     

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.     

2,2‐Di­methyl‐1‐(2,4,6‐tri­nitro­phenyl)­hydrazine

The title mol­ecule (DMPH‐H), C₈H₉N₅O₆, was investigated to provide comparison with 2,2‐di­phenyl‐1‐picryl­hydrazine, which unlike DMPH‐H is readily oxidizable to form a well known stable free radical (DPPH). The structure shows essential differences in the configuration of the hydrazine‐N atoms, the ortho‐nitro group orientations and the crystal packing. The bond angles of the di­methyl­amino N atom [107.90 (13), 108.96 (12) and 112.21 (13)°] are consistent with a tetrahedral N atom and sp³ hybridization.     

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.     

Di‐μ‐iodo‐bis{[1,1′‐methyl­enebis(3,5‐dimethyl‐1H‐pyrazole‐κN2)]copper(I)}

In the title compound, [Cu₂I₂(C₁₁H₁₆N₄)₂], each of the two crystallographically equivalent Cu atoms is tetrahedrally coordinated by two N atoms from one 1,1′‐methyl­ene­bis(3,5‐di­methyl‐1H‐pyrazole) ligand and two bridging iodide anions. The mol­ecule has a crystallographic center of symmetry located at the mid‐point of the Cu·Cu line. One H atom of the CH₂ group of the 1,1′‐methyl­ene­bis(3,5‐di­methyl‐1H‐pyrazole) ligand interacts with an iodide ion in an adjacent mol­ecule to afford pairwise intermolecular C—H·I contacts, thereby forming chains of mol­ecules running along the [101] direction.     

Hydrogen‐bonded one‐dimensional networks in 1:1 complexes of N,N′‐bis(2‐pyridyl)aryldiamines with anilic acid

The 1:1 complexes N,N′‐bis(2‐pyridyl)­benzene‐1,4‐di­amine–anilic acid (2,5‐di­hydroxy‐1,4‐benzo­quinone) (1/1), C₁₆H₁₄N₄·C₆H₄O₄, (I), and N,N′‐bis(2‐pyridyl)­bi­phenyl‐4,4′‐di­amine–anilic acid (1/1), C₂₂H₁₈N₄·C₆H₄O₄, (II), have been prepared and their solid‐state structures investigated. The component mol­ecules of these complexes are connected via conventional N—H?O and O—H?N hydrogen bonds, leading to the formation of an infinite one‐dimensional network generated by the cyclic motif R(9). The anilic acid molecules in both crystal structures lie around inversion centres and the observed bond lengths are typical for the neutral mol­ecule. Nevertheless, the pyridine C—N—C angles [120.9 (2) and 120.13 (17)° for complexes (I) and (II), respectively] point to a partial H‐atom transfer from anilic aicd to the bispyridyl­amine, and hence to H‐atom disorder in the OHN bridge. The bispyridyl­amine mol­ecules of (I) and (II) also lie around inversion centres and exhibit disorder of their central phenyl rings over two positions.     

(±)‐6‐Benzyl‐3,3‐di­methyl­morpholine‐2,5‐dione and its 5‐mono­thio and 2,5‐di­thio derivatives

The morpholine ring of the title dione, C₁₃H₁₅NO₃, shows a boat conformation that is distorted towards a twist‐boat, with the boat ends being the two Csp³ atoms of the ring. The benzyl substituent is in the favoured `exo' position. In the mono­thione derivative, (±)‐6‐benzyl‐3,3‐di­methyl‐5‐thioxo­morpholin‐2‐one, C<sub>13</sub>H<sub>15</sub>NO<sub>2</sub>S, this ring has a much flatter conformation that is midway between a boat and an envelope, with the di­methyl end being almost planar. The orientation of the benzyl group is `endo'. The di­thione derivative, (±)‐6‐benzyl‐3,3‐di­methyl­morpholine‐2,5‐di­thione, C₁₃H₁₅N­OS₂, has two symmetry‐independent mol­ecules, which show different puckering of the morpholine ring. One mol­ecule has a flattened envelope conformation distorted towards a screw‐boat, while the conformation in the other mol­ecule is similar to that in the mono­thione derivative. Intermolecular hydrogen bonds link the mol­ecules in the three compounds, respectively, into centrosymmetric dimers, infinite chains, and dimers made up of one of each of the symmetry‐independent mol­ecules.     

trans‐Di­chloro‐cis‐bis(3,6‐di­methyl­carbazolyl)‐cis‐bis­(tetra­hydro­furan)­zirconium(IV) benzene sesquisolvate

In the title compound, [ZrCl₂(C₁₄H₁₂N)₂(C₄H₈O)₂]·1.5C₆H₆, the Zr atom is pseudo‐octahedral, with two Cl atoms in trans positions and two tetra­hydro­furan mol­ecules in cis positions. The two 3,6‐di­methyl­carbazolyl ligands are in cis positions and are canted with respect to one another. The two Zr—N distances are 2.1148 (18) and 2.1236 (18) Å, and the N—Zr—N angle is 95.08 (7)°. The title compound crystallizes as the benzene solvate, with one of the benzene mol­ecules positioned on an inversion center.     

A complex containing both five‐ and six‐coordinate [bis(5‐bromosalicyli­dene)benzene‐1,2‐diimine]chloro­iron(III)

The title compound, aqua­chloro{4,4′‐di­bromo‐2,2′‐[o‐phenylenebis­(nitrilo­methyl­idyne)]­diphenolato‐O,N,N′,O′}iron(III)–chloro{4,4′‐di­bromo‐2,2′‐[o‐phenyl­enebis­(nitrilomethyli‐dyne)]diphenolato‐O,N,N′,O′}iron(III)–di­methyl­form­amide (1/1/1), [FeCl(C₂₀H₁₂Br₂N₂O₂)][FeCl(C₂₀H₁₂Br₂N₂O₂)(H₂O)]·C₃H₇NO, contains one independent five‐coordinate [FeCl(C₂₀H₁₂Br₂N₂O₂)] monomer, one six‐coordinate [FeCl(C₂₀H₁₂Br₂N₂O₂)(H₂O)] monomer and a non‐coordinating di­methyl­form­amide solvent mol­ecule in the asymmetric unit. In the five‐coordinate monomer, the Fe atom shows distorted square‐pyramidal geometry, with the N and O atoms of the ligand at the base and the Cl atom at the apex of the pyramid. In the six‐coordinate monomer, the Fe atom is in a distorted octahedral geometry and coordinated by the donor atoms of the tetrafunctional ligand in the horizontal plane, and the coordination sphere is completed by the O atom of the water mol­ecule and the Cl atom at the axial positions. The title compound contains intermolecular O—H?O hydrogen bonds. Apart from these hydrogen bonds, there are also intermolecular C—H?Cl and C—H?O contacts.     

A structural hierarchy in the hydrogen‐bonded adduct N,N′‐di­methyl­piperazine–tartaric acid–water (1/2/2): an N‐component N‐dimensional structure (N = 3) with substructures having N = 1 and 2

In the hydrated adduct N,N′‐di­methyl­piperazine‐1,4‐diium bis(3‐carboxy‐2,3‐di­hydroxy­propanoate) dihydrate, [MeNH(CH₂CH₂)₂NHMe]²⁺·2(C₄H₅O₆)^?·2H₂O or C₆H₁₆N₂²⁺·2C₄H₅O₆^?·2H₂O, formed between racemic tartaric acid and N,N′‐di­methyl­piperazine (triclinic P, Z′ = 0.5), the cations lie across centres of inversion. The anions alone form chains, and anions and water mol­ecules together form sheets; the sheets are linked by the cations to form a pillared‐layer framework. The supramolecular architecture thus takes the form of a family of N‐dimensional N‐component structures having N = 1, 2 or 3.     

Diaquabis(1,3‐propanediamine‐κ2N,N′)nickel(II) bis(sulfanilate)

The title compound, [Ni(C₃H₁₀N₂)₂(H₂O)₂](C₆H₆NO₃S)₂, contains alternating layers of sulfanilate anions and di­aqua­bis(1,3‐propane­di­amine)­nickel(II) cations. The Ni atom lies on an inversion centre and is hexacoordinated by the 1,3‐propane­di­amine ligands, which function as N,N′‐bidentate ligands, and the water mol­ecules, which are in a trans arrangement. The sulfanilate anions are arranged in layers, with the sulfonate and amine groups directed towards opposite sides of the layer. The structure is stabilized by a network of hydrogen bonding between the O and N atoms of the sulfanilate anions, the water mol­ecules, and the N atoms of the 1,3‐propane­di­amine ligands.     

trans‐[N,N′‐Bis­(salicyl­idene)­cyclo­hexane‐1,2‐diaminato]­nickel(II)–chloro­form (1/1)

In the title complex, trans‐{2,2′‐[cyclo­hexane‐1,2‐diyl­bis­(ni­t­rilo­methyl­idyne)]­di­phenol­ato‐κ⁴O,N,N′,O′}­nickel(II)–chloro­form (1/1), [Ni(C₂₀H₂₀N₂O₂)]·CHCl₃, the Ni atom has a square‐planar geometry, slightly tetrahedrally distorted. The Ni—N and Ni—O bonding distances are within the expected ranges for Ni–Schiff base derivatives. The di­imine bridge has a gauche conformation with the cyclo­hexyl ring almost coplanar with the NiN₂O₂ plane. The complex mol­ecules pack in dimers with an Ni?Ni distance of 3.59 (1) Å and form a three‐dimensional structure displaying a herring‐bone configuration. Channels are occupied by solvent mol­ecules, which are involved in C—H?O hydrogen bonds with the ligand O atoms.     

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.     

Tris(3,5‐di­methyl‐1H‐pyrazole‐1‐thio­carboxamidato‐κ2N2,N)­cobalt(III)

In the crystal structure of the title complex, [Co(C₆H₈N₃S)₃], the Co^III atom is octahedrally coordinated by three monodeprotonated bidentate 3,5‐di­methyl‐1H‐pyrazole‐1‐thio­carbox­amide ligands with two thio­carbox­amide N atoms in axial positions. The asymmetric unit contains two mol­ecules (A and B) and these mol­ecules are arranged in chains in an alternating fashion connected by N—H⋯S interactions.     

(6R*,16R*)‐9,14‐Dihydro‐6‐methyl‐6,16‐methano‐6H,16H‐[2,4]benzothiazepino[3,4‐d][1,3,5]benzoxadiazocine hydrobromide dimethylformamide hemisolvate

The title compound, C₁₉H₁₉N₂OS⁺·Br^?·0.5C₃H₇NO, is an oxygen‐bridged phenyl­pyrimidine derivative in which the heterocyclic ring is protonated, the positive charge being dispersed over both of the N atoms. Both mol­ecules in the asymmetric unit exist in an identical conformation, which consists of a central planar portion with the two terminal phenyl rings protruding from the same side of the plane. One of the independent mol­ecules forms a strong hydrogen bond with the bromide anion, while the other is hydrogen bonded to the di­methyl­form­amide solvent mol­ecule.     

The antifolate trimetrexate: ­observation of the enzyme‐binding conformation

The crystal structure of the title compound contains four 2,4‐di­amino‐5‐methyl‐6‐[(3,4,5‐tri­methoxy­anilino)­methyl]­quin­az­oline mol­ecules, two di­methyl sulfoxide mol­ecules and three water mol­ecules in the asymmetric unit, i.e. 4C₁₉H₂₃N₅O₃·2C₂H₆OS·3H₂O. All four quinazoline mol­ecules adopt trans,gauche conformations. An extensive hydrogen‐bond network involving N?N base‐pairing interactions, as well as the di­methyl sulfoxide and water mol­ecules, stabilizes the crystal structure.     

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.     

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.     

Two carbamoyl‐substituted di­hydro­pyrimidines: potential mimics of di­hydro­pyridine calcium channel blockers

The structures of two conformationally similar 1,4‐di­hydro­pyrimidines with a novel carbamoyl substitution, viz. 6‐methyl‐5‐(N‐methyl­carbamoyl)‐4‐phenyl‐1,2,3,4‐tetrahydro­py­rimidine‐2‐thione monohydrate, C₁₃H₁₅N₃OS·H₂O, (I), and 4‐(4‐chloro­phenyl)‐6‐methyl‐5‐(N‐methyl­carbamoyl)‐1,2,3,4‐tetra­hydro­pyrimidine‐2‐thione monohydrate, C₁₃H₁₄ClN₃OS·H₂O, (II), exhibit the structural features of 1,4‐di­hydro­pyridine calcium channel blockers. In both structures, the pyrimidine ring adopts a flattened boat conformation and the carbamoyl side chain is in an extended conformation with an anticlinal orientation. The phenyl ring occupies a pseudo‐axial position with respect to the pyrimidine ring in these structures. Both compounds crystallize with one mol­ecule of water, which participates in a two‐dimensional hydrogen‐bonding network. The mol­ecules are linked into dimers by N—H·S hydrogen bonds in both structures.