[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.     

A mixed crystal of imperatorin and phellopterin,with C—H...O,C—H...π and π–π interactions

The crystal structure of 9‐(3‐methyl­but‐2‐enyl­oxy)­‐7H‐furo­[3,2‐g]­chro­men‐7‐one–4‐methoxy‐9‐(3‐methyl­but‐2‐enyl­oxy)‐7H‐­furo­[3,2‐g]­chromen‐7‐one (0.926/0.074), 0.926C₁₆H₁₄O₄·0.074C₁₇H₁₆O₅, is characterized by two independent imperatorin mol­ecules in the asymmetric unit, which exhibit different side‐chain conformations. A small amount of phellopterin overlaps with one of the two imperatorin mol­ecules. The supramol­ecular structure is supported by C—H...O, C—H...π and π–π interactions.     

Azadirachtol,a tetranortriterpenoid from neem kernels

The title compound, di­methyl (?)‐(2aR,3R,4R,4aS,5R,7aS,8R,10S,10aR)‐3,8,10‐tri­hydroxy‐4‐[(2R,6R)‐2‐hydroxy‐11‐methyl‐5,7,10‐trioxatetra­cyclo­[6.3.1.0^2,60^9,11]­dodec‐3‐en‐9‐yl]‐4‐methyl­per­hydro­isobenzo­furano­[5,4,3a‐cd]­isobenzofuran‐5,10a‐di­acetate, C₂₈H₃₆O₁₃, which exhibits higher antifeedant activity than azadirachtin‐A, a known potent antifeedant, was isolated from neem kernels. The asymmetric unit of the structure contains two independent mol­ecules, which differ in the conformations of their functional groups and also in the conformations of some of the rings. The relative orientation between the decalin and furan­yl moieties is similar to that observed in the majority of azadirachtin structures, but is different from that in azadirachtin‐A. The two symmetry‐independent mol­ecules are linked into dimeric units by intermolecular O—H?O hydrogen bonds.     

Three ginkgolide hydrates from Ginkgo biloba L.: ginkgolide A monohydrate,ginkgolide C sesquihydrate and ginkgolide J dihydrate,all determined at 120 K

A low‐temperature structure of ginkgolide A monohydrate, (1R,3S,3aS,4R,6aR,7aR,7bR,8S,10aS,11aS)‐3‐(1,1‐dimethylethyl)‐hexa­hydro‐4,7b‐di­hydroxy‐8‐methyl‐9H‐1,7a‐epoxymethano‐1H,6aH‐cyclo­penta­[c]­furo­[2,3‐b]­furo­[3′,2′:3,4]­cyclopenta­[1,2‐d]­furan‐5,9,12(4H)‐trione monohydrate, C₂₀H₂₄O₉·H₂O, obtained from Mo Kα data, is a factor of three more precise than the previous room‐temperature determination. A refinement of the ginkgolide A monohydrate structure with Cu Kα data has allowed the assignment of the absolute configuration of the series of compounds. Ginkgolide C sesquihydrate, (1S,2R,3S,3aS,4R,6aR,7aR,7bR,8S,10aS,11S,11aR)‐3‐(1,1‐di­methyl­ethyl)‐hexa­hydro‐2,4,7b,11‐tetrahydroxy‐8‐methyl‐9H‐1,7a‐epoxy­methano‐1H,6aH‐cyclopenta­[c]­furo­[2,3‐b]­furo­[3′,2′:3,4]­cyclo­penta­[1,2‐d]­furan‐5,9,12(4H)‐trione sesquihydrate, C₂₀H₂₄O₁₁·1.5H₂O, has two independent diterpene mol­ecules, both of which exhibit intramolecular hydrogen bonding between OH groups. Ginkgolide J dihydrate, (1S,2R,3S,3aS,4R,6aR,7aR,7bR,8S,10aS,11aS)‐3‐(1,1‐di­methyl­ethyl)‐hexa­hydro‐2,4,7b‐tri­hydroxy‐8‐methyl‐9H‐1,7a‐epoxy­methano‐1H,6aH‐cyclo­penta­[c]­furo­[2,3‐b]furo[3′,2′:3,4]­cyclo­penta­[1,2‐d]­furan‐5,9,12(4H)‐trione dihydrate, C₂₀H₂₄O₁₀·2H₂O, has the same basic skeleton as the other ginkgolides, with its three OH groups having the same configurations as those in ginkgolide C. The conformations of the six five‐membered rings are quite similar across ­ginkgolides A–C and J, except for the A and F rings of ginkgolide A.     

Inclusion of HNEt3+ in an acyclic tetraphenolate

The acyclic tetraphenolic derivative 2,2′‐methyl­ene­bis[6‐(3‐tert‐butyl‐2‐hydroxy‐5‐methyl­benzyl)‐4‐methyl­phenol] reacts with excess triethyl­amine in aceto­nitrile to form a molecular complex, i.e. triethyl­ammonium 2‐(3‐tert‐butyl‐2‐hydroxy‐5‐methylbenzyl)‐6‐[3‐(3‐tert‐butyl‐2‐hydroxy‐5‐methylbenzyl)‐2‐hydroxy‐5‐methylbenzyl]‐4‐methylphenolate aceto­nitrile sol­vate, C₆H₁₆N⁺·­C₃₉H₄₇O₄^?·­C₂H₃N, where the organic HNEt₃⁺ cation is included in the partial cone defined by the aromatic faces of the acyclic poly­phenolate.     

Two N,N‐dimethylbiguanidium salts displaying double hydrogen bonds to the counter‐ions

The crystal structures of N,N‐di­methyl­biguanidium oxalate monohydrate, C₄H₁₃N₅²⁺·C₂O₄²⁻·H₂O, (I), and N,N‐di­methyl­biguanidium sulfate monohydrate, C₄H₁₃N₅²⁺·SO₄²⁻·H₂O, (II), show that both compounds contain the same N,N‐di­methyl­biguanidium dication. In (I), two independent oxalate ions lie about inversion centres. Strong double hydrogen bonds, with D⋯A distances of 2.658 (2) and 2.830 (3) Å in (I), and 2.722 (3) and 2.815 (3) Å in (II), are present between N atoms of the N,N‐di­methyl­biguanidium moieties and either the carboxyl­ate group of the oxalate anion or the sulfate anion.     

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.     

The 1:1 adduct of Kemp's triacid with 2‐aminopyridine

The crystal structure determination of the molecular proton‐transfer adduct of Kemp's triacid (cis‐cis‐1,3,5‐tri­methyl­cyclo­hexane‐1,3,5‐tri­carboxylic acid, KTA) with 2‐amino­pyridine (2‐APY), namely 2‐amino­pyridinium 3,5‐di­carboxy‐1,3,5‐tri­methyl­cyclo­hexane­carboxyl­ate, 2‐APY⁺·KTA^? or C₅H₇N₂⁺·C₁₂H₁₇O₆^?, has revealed a centrosymmetric hydrogen‐bonded cyclic KTA homodimer repeating unit [O?O 2.524 (4) Å] linked into a polymer structure through the pyridinium and amino groups of the 2‐APY mol­ecule [O?N 2.736 (4), 2.989 (4) and 2.999 (4) Å].     

Ribbons of hydrogen‐bonded rings in the 1:2 complex of pyromellitic acid and di­methyl sulfoxide

In the title complex, pyromellitic acid–di­methyl sulfoxide (1/­2), C₁₀H₆O₈·2C₂H₆OS, mol­ecules of pyromellitic acid (1,2,4,5‐benzene­tetra­car­box­ylic acid) and di­methyl sulfoxide, the latter being well ordered, are linked to each other by O—­H⃛O hydrogen bonds. The formula unit displays crystallographic inversion symmetry. The packing consists of ribbons of hydrogen‐bonded rings that can be described by graph set C(10)R(18).     

Mammeigin

Single crystals of the phenyl­coumarin named mammeigin (or mammea A/AA cycle D) [systematic name: 5‐hydroxy‐8,8‐dimethyl‐6‐(3‐methyl­butanoyl)‐4‐phenyl‐2H,8H‐pyrano[2,3‐f]chromen‐2‐one], C₂₅H₂₄O₅, were obtained in the course of a chemotaxonomic study of the Guttiferae family. Mammeigin was extracted from the fruits of Kilmeyera pumila. The structure reveals an infinite three‐dimensional network stabilized by non‐classical inter­molecular hydrogen bonds.     

A dimeric constrained‐geometry titanium complex linked by double Ti–CH2–Al–CH2 heterocycles

In the structure of bis({N‐[di­methyl(1η⁵‐2,3,4,6‐tetra­methyl­in­den­yl)­silyl]­cyclo­hexyl­amido‐1κN}(methyl‐3κC)‐di‐μ₃‐methyl­ene‐1:2:3κ³C;1:3:3′κ³C‐tris(pentafluorophenyl‐2κC)titanium) benzene disolvate, [Me₂Si(η⁵‐2,3,4,6‐Me₄C₉H₂)(C₆H₁₁N)]Ti[(μ₃‐CH₂)Al(C₆F₅)₃][AlMe(μ₃‐CH₂)]₂ or [Ti₂(C₂₁H₇AlF₁₅)₂(C₂₁H₃₁NSi)₂]·2C₆D₆, the dimer is located on an inversion center, and the two Ti centers are linked by double Ti(μ₃‐CH₂)Al(C₆F₅)₃AlMe(μ₃‐CH₂) heterocycles. The electron‐deficient Ti centers are further stabilized by two α‐agostic interactions between Ti and one H atom of each bridging methyl­ene group.     

Four cytotoxic N4‐substituted thiosemicarbazones derived from 2‐hydroxynaphthalene‐1‐carboxaldehyde

The X‐ray crystal structures are reported of four novel and potentially O,N,S‐tridentate donor ligands that demonstrate antitumour activity. These ligands are 1‐[(4‐methyl­thio­semicarbazono)methyl]‐2‐naphthol, C₁₃H₁₃N₃OS, (III), 1‐[(4‐ethylthio­semicarbazono)­methyl]‐2‐naphthol, C₁₄H₁₅N₃OS, (IV), 1‐[(4‐phenyl­thio­semicarbazono)­methyl]‐2‐naphthol, C₁₈H₁₅N₃OS, (V), and 1‐[(4,4‐di­methyl­thio­semicarbazono)­methyl]‐2‐naphthol di­methyl sulfoxide solvate, C₁₄H₁₅N₃OS·C₂H₆OS, (VI). These chelators are N4‐substituted thio­semicarbazones, each based on the same parent aldehyde, namely 2‐­zhydroxynaphthalene‐1‐carboxaldehyde isonicotinoylhydrazone. Conformational variations within this series are discussed in relation to the optimum conformation for metal‐ion binding.     

(4R,4aR,6S,7S,7aS)‐6‐Hydro­xy‐7‐hy­droxy­methyl‐4‐methyl­per­hydro­cyclo­penta­[c]­pyran‐1‐one chloro­form solvate from Valeriana laxiflora

The structure of an iridolactone isolated from Valeriana laxiflora was established as (4R,4aR,6S,7S,7aS)‐6‐hydroxy‐7‐hydroxy­methyl‐4‐methyl­per­hydro­cyclo­penta­[c]­pyran‐1‐one chloro­form solvate, C₁₀H₁₆O₄·CHCl₃. The two rings are cis‐fused. The δ‐lactone ring adopts a slightly twisted half‐chair conformation with approximate planarity of the lactone group and the cyclo­pentane ring adopts an envelope conformation. The hydroxy group, the hydroxymethyl group and the methyl group all have β orientations. The absolute configuration was determined using anomalous dispersion data enhanced by the adventitious inclusion of a chloro­form solvent mol­ecule. Hydro­gen bonding, crystal packing and ring conformations are discussed in detail.     

Redetermination of the twinned structure of triacetone amine ­monohydrate

The structure of triacetone amine monohydrate (systematic name: 2,2,6,6‐tetra­methyl­piperidin‐4‐one monohydrate), C₉H₁₇NO·H₂O, has been redetermined at 180 K. The compound crystallizes in space group P2₁/c with a monoclinic angle of 90.084 (3)°. All crystals examined exhibited twinning and appeared orthorhombic, with a unit‐cell volume half that of the true volume.     

Influence of 1,4‐dioxane solvent inclusion on the crystal structure of 5,5′‐diphenyl‐2,2′‐(p‐phenylene)di‐1,3‐oxazole (POPOP)

Crystallization of 5,5′‐diphenyl‐2,2′‐(p‐phenylene)di‐1,3‐oxazole (POPOP), C₂₄H₁₆N₂O₂, from chloroform or 1,4‐dioxane yielded crystals in pure and solvated forms, respectively. The solvated crystals of POPOP were found to contain 1,4‐dioxane in a strict 1:2 compound–solvent stoichiometry, C₂₄H₁₆N₂O₂·C₄H₈O₂, thus being a defined solvent‐inclusion compound. The crystal system is monoclinic in both cases and the asymmetric unit of the cell contains only half of the molecule (plus one dioxane molecule in the case of the solvated structure), owing to the centrosymmetry of the di‐1,3‐oxazole molecule.     

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.     

Intermolecular stacking in pyrazolo[3,4‐d]pyrimidine‐based pentamethylene‐linked flexible ­molecules

The crystal structures of 1‐{5‐[4,6‐bis­(methyl­sulfanyl)‐2H‐py­razolo­[3,4‐d]­pyrimidin‐2‐yl]­pentyl}‐6‐methyl­sulfanyl‐4‐(pyr­rolidin‐1‐yl)‐1H‐pyrazolo­[3,4‐d]­pyrimidine, C₂₂H₂₉N₉S₃, and 6‐methyl­sulfanyl‐1‐{5‐[6‐methyl­sulfanyl‐4‐(pyrrolidin‐1‐yl)‐2H‐pyrazolo­[3,4‐d]­pyrimidin‐2‐yl]­pentyl}‐4‐(pyrrolidin‐1‐yl)‐1H‐pyrazolo­[3,4‐d]­pyrimidine, C₂₅H₃₄N₁₀S₂, which differ in having either a pyrrolidine substituent or a methylsulfanyl group, show intermolecular stacking due to aromatic π–π interactions between the pyrazolo­[3,4‐d]­pyrimidine rings.     

Two salts of di‐p‐toluoyltartaric acid with aromatic amines

The structures of bis­[(R)‐(+)‐1‐phenyl­ethyl­ammonium] (2R,3R)‐(−)‐2,3‐di‐p‐toluoyloxybutane­dioate methanol disolvate monohydrate, 2C₈H₁₂N⁺·C₂₀H₁₆O₈²⁻·2CH₄O·H₂O, (I), and bis­(benzyl­ammonium) (2R,3R)‐(−)‐2,3‐di‐p‐toluoyl­oxy­butane­­dioate dihydrate, 2C₇H₁₀N⁺·C₂₀H₁₆O₈²⁻·2H₂O, (II), exhibit extensive hydrogen bonding, with (N—)H⋯O and (O—)H⋯O distances in the ranges 2.716 (2)–2.929 (3) and 2.687 (2)–2.767 (2) Å, respectively, in (I), and 2.673 (2)–2.888 (2) and 2.785 (2)–2.931 (2) Å, respectively, in (II). The amine groups are protonated and the carboxyl­ate groups of the tartrate anions are fully deprotonated. The conformation of the toluoyltartrate anion and its mol­ecular parameters are similar in both structures.     

The molecular and supramolecular structures of the isomeric compounds 5,7‐di­methoxy­imidazo­[1,2‐c]­pyrimidine and 7‐methoxy‐1‐methyl­imidazo­[1,2‐a]­pyrimidin‐5(1H)‐one

The supramolecular structures of the isomeric compounds 5,7‐di­methoxy­imidazo­[1,2‐c]­pyrimidine, C₈H₉N₃O₂, (I), and 7‐methoxy‐1‐methyl­imidazo­[1,2‐a]­pyrimidin‐5(1H)‐one, C₈H₉N₃O₂, (II), are determined by weak C—H⃛N and C—H⃛O hydrogen bonds in (I), which generate alternating linked centrosymmetric R(8) and R(10) rings that form a ribbon running parallel to the c axis, and by C—H⃛O bonds in (II), which link the mol­ecules into sheets comprising centro­symmetric R(10) and R(22) rings.     

7‐Carboxyl­ato‐8‐hydroxy‐2‐methyl­quinolinium monohydrate and 7‐carboxy‐8‐hydroxy‐2‐methyl­quinolinium chloride monohydrate at 100 K

Both 7‐carboxyl­ato‐8‐hydroxy‐2‐methyl­quinolinium monohydrate, C₁₁H₉NO₃·H₂O, (I), and 7‐carboxy‐8‐hydroxy‐2‐methyl­quinolinium chloride monohydrate, C₁₁H₁₀NO₃⁺·Cl⁻·H₂O, (II), crystallize in the centrosymmetric P space group. Both compounds display an intramolecular O—H⋯O hydrogen bond involving the hydroxy group; this hydrogen bond is stronger in (I) due to its zwitterionic character [O⋯O = 2.4449 (11) Å in (I) and 2.5881 (12) Å in (II)]. In both crystal structures, the HN⁺ group participates in the stabilization of the structure via intermolecular hydrogen bonds with water mol­ecules [N⋯O = 2.7450 (12) Å in (I) and 2.8025 (14) Å in (II)]. In compound (II), a hydrogen‐bond network connects the Cl⁻ anion to the carboxylic acid group [Cl⋯O = 2.9641 (11) Å] and to two water mol­ecules [Cl⋯O = 3.1485 (10) and 3.2744 (10) Å].